diff --git a/cif_twin.dic b/cif_twin.dic index 22b9532..234ac6c 100644 --- a/cif_twin.dic +++ b/cif_twin.dic @@ -9,36 +9,35 @@ # # ############################################################################## - data_CIF_TWIN - _dictionary.title CIF_TWIN - _dictionary.class Instance - _dictionary.version 3.1 - _dictionary.date 2024-05-15 - _dictionary.uri www.iucr.org/cif/dic/cif_twin.dic - _dictionary.ddl_conformance 3.11.09 - _dictionary.namespace TwinCrys - _description.text + _dictionary.title CIF_TWIN + _dictionary.class Instance + _dictionary.version 3.1 + _dictionary.date 2024-11-21 + _dictionary.uri www.iucr.org/cif/dic/cif_twin.dic + _dictionary.ddl_conformance 4.2.0 + _dictionary.namespace CifCore + _description.text ; The DICTIONARY group defines the data items used to specify the the twinning aspects of crystals in a crystallographic study. - ; save_TWIN_GROUP - _definition.id TWIN_GROUP - _definition.scope Category - _definition.class Head - _definition.update 2024-05-15 - _description.text + _definition.id TWIN_GROUP + _definition.scope Category + _definition.class Head + _definition.update 2024-05-15 + _description.text ; The TWIN_GROUP data items describe atomic information used in crystallographic structure studies. ; - _name.category_id CIF_TWIN - _name.object_id TWIN_GROUP + _name.category_id CIF_TWIN + _name.object_id TWIN_GROUP + _import.get [ {'dupl':Ignore 'file':cif_core.dic 'mode':Full 'save':CIF_CORE_HEAD} @@ -46,14 +45,13 @@ save_TWIN_GROUP save_ - save_TWIN - _definition.id TWIN - _definition.scope Category - _definition.class Set - _definition.update 2014-06-20 - _description.text + _definition.id TWIN + _definition.scope Category + _definition.class Set + _definition.update 2024-11-21 + _description.text ; Data items in the TWIN category record general details about @@ -64,161 +62,225 @@ save_TWIN by Massimo Nespolo, February 3, 2009. http://www.crystallography.fr/mathcryst/twins.htm . ; - _name.category_id TWIN_GROUP - _name.object_id TWIN + _name.category_id TWIN_GROUP + _name.object_id TWIN + _description_example.case +; + _twin.formation_mechanism gt + _twin.dimensionality triperiodic + _twin.morphology polysynthetic + _twin.special_details + ; This is an example of a twin in space group P 32 + by the 2 x,x,0 twin operation. + ; -save_ + loop_ + _twin_individual.id + _twin_individual.mass_fraction_refined + _twin_individual.twin_lattice_type + _twin_individual.twin_matrix_11 + _twin_individual.twin_matrix_12 + _twin_individual.twin_matrix_13 + _twin_individual.twin_matrix_21 + _twin_individual.twin_matrix_22 + _twin_individual.twin_matrix_23 + _twin_individual.twin_matrix_31 + _twin_individual.twin_matrix_32 + _twin_individual.twin_matrix_33 + 1 0.545(2) ref 1 0 0 0 1 0 0 0 1 + 2 0.455(2) mt_II 0 1 0 1 0 0 0 0 -1 + loop_ + _twin_refln.datum_id + _twin_refln.individual_id + _twin_refln.index_h + _twin_refln.index_k + _twin_refln.index_l + _twin_refln.F_squared_calc + _twin_refln.F_squared_meas + _twin_refln.F_squared_sigma + _twin_refln.include_status + 1 1 -1 1 -32 40.17 55.86 7.39 o + 1 2 1 -1 32 40.17 55.86 7.39 o + 2 1 0 1 -32 125.83 145.63 9.36 o + 2 2 1 0 32 125.83 145.63 9.36 o + 3 1 1 1 -32 10.33 30.89 7.39 o + 3 2 1 1 32 10.33 30.89 7.39 o + 4 1 -3 2 -32 28.26 26.84 9.47 o + 4 2 2 -3 32 28.26 26.84 9.47 o + 5 1 -2 2 -32 4.31 13.21 9.78 o + 5 2 2 -2 32 4.31 13.21 9.78 o + 6 1 -1 2 -32 10.71 17.48 9.88 o + 6 2 2 -1 32 10.71 17.48 9.88 o + 7 1 0 2 -32 13.94 37.66 10.51 o + 7 2 2 0 32 13.94 37.66 10.51 o + 8 1 1 2 -32 58.60 75.41 9.88 o + 8 2 2 1 32 58.60 75.41 9.88 o + 9 1 -2 3 -32 27.75 41.40 8.01 o + 9 2 3 -2 32 27.75 41.40 8.01 o + 10 1 -1 3 -32 59.22 65.53 8.11 o + 10 2 3 -1 32 59.22 65.53 8.11 o +; + _description_example.detail +; + The twinning example presented here shows twinning by merohedry for + a trigonal crystal system. The simulated space group is P 32 2 1, but + the true space group is P 32. The twin operation chosen is 2: x, x, 0 in + P 32 2 1 corresponding to operation (by rows) 0, 1, 0 / 1, 0, 0 / 0, 0, -1 + [see Table 11.2.2.1 of International Tables for Crystallography + (2005), Vol. A]. + + The TWIN_REFLN loop gives the properties of each diffraction peak + (identified by _twin_refln_datum_id) which is indexed + to both the twin individuals. + + In each of the loops shown in this example the first items on a line + are the list reference. While the list reference must be present + in every loop, it is not necessary that it should be declared as the + first item in the loop. +; + +save_ save_twin.dimensionality - _definition.id '_twin.dimensionality' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_dimensionality' - _description.text + _definition.id '_twin.dimensionality' + _alias.definition_id '_twin_dimensionality' + _definition.update 2014-06-20 + _description.text ; The degree of overlap between the twin lattices. Most twin lattice symmetry (TLS) and twin lattice quasi-symmetry (TLQS) twins as defined by Donnay and Donnay will be triperiodic. - + Reference: Donnay, G. & Donnay, J. D. H. (1974). Can. Mineral. 12, 422-425. ; - _name.category_id twin - _name.object_id dimensionality - _type.purpose State - _type.source Assigned - _type.container Single - _type.contents Code + _name.category_id twin + _name.object_id dimensionality + _type.purpose State + _type.source Assigned + _type.container Single + _type.contents Code + loop_ - _enumeration_set.state - _enumeration_set.detail - triperiodic 'common lattice in three dimensions' - diperiodic 'common lattice in two dimensions' - monoperiodic 'common lattice in one dimension' + _enumeration_set.state + _enumeration_set.detail + triperiodic 'common lattice in three dimensions' + diperiodic 'common lattice in two dimensions' + monoperiodic 'common lattice in one dimension' save_ - save_twin.formation_mechanism - _definition.id '_twin.formation_mechanism' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_formation_mechanism' - _description.text + _definition.id '_twin.formation_mechanism' + _alias.definition_id '_twin_formation_mechanism' + _definition.update 2014-06-20 + _description.text ; A description of the method of twin formation. ; - _name.category_id twin - _name.object_id formation_mechanism - _type.purpose State - _type.source Assigned - _type.container Single - _type.contents Code + _name.category_id twin + _name.object_id formation_mechanism + _type.purpose State + _type.source Assigned + _type.container Single + _type.contents Code + loop_ - _enumeration_set.state - _enumeration_set.detail - gt 'growth twin formed during crystal growth' - tt 'transformation twin formed during phase transition' - mt 'mechanical twin formed as a result of mechanical action' + _enumeration_set.state + _enumeration_set.detail + gt 'growth twin formed during crystal growth' + tt 'transformation twin formed during phase transition' + mt 'mechanical twin formed as a result of mechanical action' save_ - save_twin.morphology - _definition.id '_twin.morphology' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_morphology' - _description.text + _definition.id '_twin.morphology' + _alias.definition_id '_twin_morphology' + _definition.update 2014-06-20 + _description.text ; The physical relationship of the different twins to one another. ; - _name.category_id twin - _name.object_id morphology - _type.purpose State - _type.source Assigned - _type.container Single - _type.contents Code + _name.category_id twin + _name.object_id morphology + _type.purpose State + _type.source Assigned + _type.container Single + _type.contents Code + loop_ - _enumeration_set.state - _enumeration_set.detail - contact 'separated by a surface' - penetration 'sharing a volume' - simple 'individuals are not repeated' - polysynthetic 'individuals repeat in approximately linear arrangement' - cyclic 'individuals repeat in closed edifice' + _enumeration_set.state + _enumeration_set.detail + contact + 'separated by a surface' + penetration + 'sharing a volume' + simple + 'individuals are not repeated' + polysynthetic + 'individuals repeat in approximately linear arrangement' + cyclic + 'individuals repeat in closed edifice' save_ - save_twin.special_details - _definition.id '_twin.special_details' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_special_details' - _description.text + _definition.id '_twin.special_details' + _alias.definition_id '_twin_special_details' + _definition.update 2014-06-20 + _description.text ; Information about twinning in the sample not contained in other data items. ; - _name.category_id twin - _name.object_id special_details - _type.purpose Describe - _type.source Recorded - _type.container Single - _type.contents Text - loop_ + _name.category_id twin + _name.object_id special_details + _type.purpose Describe + _type.source Recorded + _type.container Single + _type.contents Text _description_example.case - ; Individuals 3 and 4 arise from form (I) following an enantiotropic phase transition by sudden cooling in a cryostat to 173K. -; +; save_ - save_TWIN_INDIVIDUAL - _definition.id TWIN_INDIVIDUAL - _definition.scope Category - _definition.class Loop - _definition.update 2014-06-20 - _description.text + _definition.id TWIN_INDIVIDUAL + _definition.scope Category + _definition.class Loop + _definition.update 2014-06-20 + _description.text ; Data items in the TWIN_INDIVIDUAL category describe properties of each twinned individual, and the symmetry relationships between the individuals. ; - _name.category_id TWIN - _name.object_id TWIN_INDIVIDUAL - loop_ - _category_key.name '_twin_individual.id' + _name.category_id TWIN + _name.object_id TWIN_INDIVIDUAL + _category_key.name '_twin_individual.id' save_ - save_twin_individual.id - _definition.id '_twin_individual.id' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_id' - _description.text + _definition.id '_twin_individual.id' + _alias.definition_id '_twin_individual_id' + _definition.update 2014-06-20 + _description.text ; The unique identifier for this twin individual. @@ -226,49 +288,43 @@ save_twin_individual.id is the identity matrix is called the reference twin. It is recommended that the reference twin be labelled '1'. ; - _name.category_id twin_individual - _name.object_id id - _type.purpose Encode - _type.source Assigned - _type.container Single - _type.contents Code + _name.category_id twin_individual + _name.object_id id + _type.purpose Encode + _type.source Assigned + _type.container Single + _type.contents Code save_ - save_twin_individual.mass_fraction_refined - _definition.id '_twin_individual.mass_fraction_refined' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_mass_fraction_refined' - _description.text + _definition.id '_twin_individual.mass_fraction_refined' + _alias.definition_id '_twin_individual_mass_fraction_refined' + _definition.update 2014-06-20 + _description.text ; The refined mass fraction of this twin individual; the sum of all mass fractions must equal unity within the limits of experimental uncertainty. ; - _name.category_id twin_individual - _name.object_id mass_fraction_refined - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Real - _enumeration.range 0:1.0 + _name.category_id twin_individual + _name.object_id mass_fraction_refined + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Real + _enumeration.range 0:1.0 save_ - save_twin_individual.twin_lattice_type - _definition.id '_twin_individual.twin_lattice_type' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_twin_lattice_type' - _description.text + _definition.id '_twin_individual.twin_lattice_type' + _alias.definition_id '_twin_individual_twin_lattice_type' + _definition.update 2014-06-20 + _description.text ; Identification of the symmetry relationships between the @@ -276,35 +332,33 @@ save_twin_individual.twin_lattice_type for Crystallography (2004), Vol. C, Chapter 1.3. The twin with the identity matrix should be denoted as 'ref'. ; - _name.category_id twin_individual - _name.object_id twin_lattice_type - _type.purpose State - _type.source Assigned - _type.container Single - _type.contents Code + _name.category_id twin_individual + _name.object_id twin_lattice_type + _type.purpose State + _type.source Assigned + _type.container Single + _type.contents Code + loop_ - _enumeration_set.state - _enumeration_set.detail - ref 'reference twin' - mt_I 'merohedral class I (simple inversion)' - mt_II 'merohedral class II (mirror or twofold)' - mt_I+II 'class I and II simultaneously present' - rmt 'reticular merohedral' - pmt 'pseudo-merohedral' - rpmt 'reticular pseudo-merohedral' - nmt 'non-merohedral' + _enumeration_set.state + _enumeration_set.detail + ref 'reference twin' + mt_I 'merohedral class I (simple inversion)' + mt_II 'merohedral class II (mirror or twofold)' + mt_I+II 'class I and II simultaneously present' + rmt 'reticular merohedral' + pmt 'pseudo-merohedral' + rpmt 'reticular pseudo-merohedral' + nmt 'non-merohedral' save_ - save_twin_individual.twin_matrix - _definition.id '_twin_individual.twin_matrix' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_twin_matrix' - _description.text + _definition.id '_twin_individual.twin_matrix' + _alias.definition_id '_twin_individual_twin_matrix' + _definition.update 2014-06-20 + _description.text ; The matrix U that multiplies the Miller indices h,k,l @@ -315,16 +369,14 @@ save_twin_individual.twin_matrix The reference twin must have U = I, the identity matrix. ; - _name.category_id twin_individual - _name.object_id twin_matrix - _type.purpose Number - _type.source Derived - _type.container Matrix - _type.contents Real - loop_ - _method.purpose + _name.category_id twin_individual + _name.object_id twin_matrix + _type.purpose Number + _type.source Derived + _type.container Matrix + _type.contents Real + _method.purpose Evaluation _method.expression - Evaluation ; with t as twin_individual @@ -332,271 +384,319 @@ save_twin_individual.twin_matrix [[ t.twin_matrix_11, t.twin_matrix_12, t.twin_matrix_13 ], [ t.twin_matrix_21, t.twin_matrix_22, t.twin_matrix_23 ], [ t.twin_matrix_31, t.twin_matrix_32, t.twin_matrix_33 ]] -; +; save_ - save_twin_individual.twin_matrix_11 - _definition.id '_twin_individual.twin_matrix_11' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_twin_matrix_11' - _description.text + _definition.id '_twin_individual.twin_matrix_11' + _alias.definition_id '_twin_individual_twin_matrix_11' + _definition.update 2014-06-20 + _description.text ; The [1,1] element of the matrix U in _twin_individual.twin_matrix. ; - _name.category_id twin_individual - _name.object_id twin_matrix_11 - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_individual + _name.object_id twin_matrix_11 + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Real save_ - save_twin_individual.twin_matrix_12 - _definition.id '_twin_individual.twin_matrix_12' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_twin_matrix_12' - _description.text + _definition.id '_twin_individual.twin_matrix_12' + _alias.definition_id '_twin_individual_twin_matrix_12' + _definition.update 2014-06-20 + _description.text ; The [1,2] element of the matrix U in _twin_individual.twin_matrix. ; - _name.category_id twin_individual - _name.object_id twin_matrix_12 - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_individual + _name.object_id twin_matrix_12 + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Real save_ - save_twin_individual.twin_matrix_13 - _definition.id '_twin_individual.twin_matrix_13' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_twin_matrix_13' - _description.text + _definition.id '_twin_individual.twin_matrix_13' + _alias.definition_id '_twin_individual_twin_matrix_13' + _definition.update 2014-06-20 + _description.text ; The [1,3] element of the matrix U in _twin_individual.twin_matrix. ; - _name.category_id twin_individual - _name.object_id twin_matrix_13 - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_individual + _name.object_id twin_matrix_13 + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Real save_ - save_twin_individual.twin_matrix_21 - _definition.id '_twin_individual.twin_matrix_21' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_twin_matrix_21' - _description.text + _definition.id '_twin_individual.twin_matrix_21' + _alias.definition_id '_twin_individual_twin_matrix_21' + _definition.update 2014-06-20 + _description.text ; The [2,1] element of the matrix U in _twin_individual.twin_matrix. ; - _name.category_id twin_individual - _name.object_id twin_matrix_21 - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_individual + _name.object_id twin_matrix_21 + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Real save_ - save_twin_individual.twin_matrix_22 - _definition.id '_twin_individual.twin_matrix_22' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_twin_matrix_22' - _description.text + _definition.id '_twin_individual.twin_matrix_22' + _alias.definition_id '_twin_individual_twin_matrix_22' + _definition.update 2014-06-20 + _description.text ; The [2,2] element of the matrix U in _twin_individual.twin_matrix. ; - _name.category_id twin_individual - _name.object_id twin_matrix_22 - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_individual + _name.object_id twin_matrix_22 + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Real save_ - save_twin_individual.twin_matrix_23 - _definition.id '_twin_individual.twin_matrix_23' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_twin_matrix_23' - _description.text + _definition.id '_twin_individual.twin_matrix_23' + _alias.definition_id '_twin_individual_twin_matrix_23' + _definition.update 2014-06-20 + _description.text ; The [3,2] element of the matrix U in _twin_individual.twin_matrix. ; - _name.category_id twin_individual - _name.object_id twin_matrix_23 - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_individual + _name.object_id twin_matrix_23 + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Real save_ - save_twin_individual.twin_matrix_31 - _definition.id '_twin_individual.twin_matrix_31' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_twin_matrix_31' - _description.text + _definition.id '_twin_individual.twin_matrix_31' + _alias.definition_id '_twin_individual_twin_matrix_31' + _definition.update 2014-06-20 + _description.text ; The [1,3] element of the matrix U in _twin_individual.twin_matrix. ; - _name.category_id twin_individual - _name.object_id twin_matrix_31 - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_individual + _name.object_id twin_matrix_31 + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Real save_ - save_twin_individual.twin_matrix_32 - _definition.id '_twin_individual.twin_matrix_32' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_twin_matrix_32' - _description.text + _definition.id '_twin_individual.twin_matrix_32' + _alias.definition_id '_twin_individual_twin_matrix_32' + _definition.update 2014-06-20 + _description.text ; The [2,3] element of the matrix U in _twin_individual.twin_matrix. ; - _name.category_id twin_individual - _name.object_id twin_matrix_32 - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_individual + _name.object_id twin_matrix_32 + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Real save_ - save_twin_individual.twin_matrix_33 - _definition.id '_twin_individual.twin_matrix_33' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_individual_twin_matrix_33' - _description.text + _definition.id '_twin_individual.twin_matrix_33' + _alias.definition_id '_twin_individual_twin_matrix_33' + _definition.update 2014-06-20 + _description.text ; The [3,3] element of the matrix U in _twin_individual.twin_matrix. ; - _name.category_id twin_individual - _name.object_id twin_matrix_33 - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_individual + _name.object_id twin_matrix_33 + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Real save_ - save_TWIN_REFLN - _definition.id TWIN_REFLN - _definition.scope Category - _definition.class Loop - _definition.update 2014-06-20 - _description.text + _definition.id TWIN_REFLN + _definition.scope Category + _definition.class Loop + _definition.update 2024-11-21 + _description.text ; Items in the TWIN_REFLN category tabulate the calculated values of F^2^ - for each peak observed in the diffraction pattern, together with the - measured value of F^2^. The calculated F^2^ for an observed peak is - a weighted sum of the contribution of all the twin components. The + for each peak observed in the diffraction pattern, together with the + measured value of F^2^. The calculated F^2^ for an observed peak is + a weighted sum of the contribution of all the twin components. The calculated structure factor for each twin contribution can also be given. ; - _name.category_id TWIN - _name.object_id TWIN_REFLN + _name.category_id TWIN + _name.object_id TWIN_REFLN + loop_ - _category_key.name - '_twin_refln.datum_id' '_twin_refln.individual_id' + _category_key.name + '_twin_refln.datum_id' + '_twin_refln.individual_id' -save_ + loop_ + _description_example.case + _description_example.detail +; + loop_ + _twin_refln.datum_id + _twin_refln.individual_id + _twin_refln.index_h + _twin_refln.index_k + _twin_refln.index_l + _twin_refln.F_squared_meas + _twin_refln.F_squared_sigma + _twin_refln.include_status + + 1 1 1 0 0 1.03 0.18 o + 1 3 1 0 0 1.03 0.18 o + 2 1 2 0 0 1290.01 55.59 o + 2 3 2 0 0 1290.01 55.59 o + 3 1 3 0 0 2.59 0.42 o + 3 3 3 0 0 2.59 0.42 o + 4 1 4 0 0 30.98 1.47 o + 4 3 4 0 0 30.98 1.47 o + 5 1 5 0 0 1.97 0.96 o + 5 3 5 0 0 1.97 0.96 o + 6 1 6 0 0 1.55 1.14 o + 6 2 6 1 2 1.55 1.14 o + 6 3 6 0 0 1.55 1.14 o + 6 4 6 1 2 1.55 1.14 o + 7 1 -6 1 0 0.47 1.06 o + 7 2 6 2 2 0.47 1.06 o +; +; + This partial listing describes seven observed diffraction peaks + in a four-individual twin by non-merohedry. The reference individual + is 1. Reflections from the other three individuals 2, 3 and 4 are + present only if these cannot be experimentally separated from the + reference individual. +; +; + loop_ + _twin_refln.datum_id + _twin_refln.individual_id + _twin_refln.index_h + _twin_refln.index_k + _twin_refln.index_l + _twin_refln.F_squared_calc + _twin_refln.F_squared_meas + _twin_refln.F_squared_sigma + _twin_refln.include_status + + 620 1 1 -6 -3 200.22 207.88 3.35 o + 621 1 -1 6 3 225.34 224.15 3.62 o + 622 2 -1 6 3 184.64 196.34 3.95 o + 623 1 -1 -6 -3 173.28 181.13 3.06 o + 624 2 -1 -6 -3 143.40 152.05 2.78 o + 625 1 1 6 3 204.45 204.38 4.48 o + 625 2 3 -6 1 204.45 204.38 4.48 o + 626 1 3 -6 -3 240.97 241.19 3.75 o + 626 2 -3 6 3 240.97 241.19 3.75 o + 627 1 3 6 3 288.54 281.53 4.31 o + 627 2 -3 -6 -3 288.54 281.53 4.31 o + 628 1 -5 -6 -3 179.56 176.35 5.36 o + 628 2 -3 6 5 179.56 176.35 5.36 o + 629 1 5 6 3 235.04 238.84 4.06 o + 629 2 -5 -6 -3 235.04 238.84 4.06 o +; +; + This example is taken from Colombo Young & Gladfelter + [Inorg. Chem. (2000), 39, 4621-4624]. + Two structures of nitronium tetranitratogallate + are reported as a result of an enantiotropic phase transition. + The higher-temperature phase is in the tetragonal space group I-4, + while the lower-temperature phase is a twin by non-merohedry + in space group I2. + The individuals are enantiomorphic as a result of the phase transition. + In the listing it is clear that datums 620-624 do not contain + overlapping reflections, whereas datums 625-629 contain contributions + from both twins. +; +save_ save_twin_refln.datum_id - _definition.id '_twin_refln.datum_id' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_refln_datum_id' - _description.text + _definition.id '_twin_refln.datum_id' + _alias.definition_id '_twin_refln_datum_id' + _definition.update 2014-06-20 + _description.text ; This item serves to identify an observed diffraction peak. It may include contributions from one or more twin components and so may appear more than once in the list. The values of _twin_refln.F_squared_calc and - _twin_refln.F_squared_meas indexed by _twin_refln.datum_id + _twin_refln.F_squared_meas indexed by _twin_refln.datum_id include the contributions from all the twins. - The diffraction peak is indexed by _twin_refln.index_hkl - referred to the cell of the twin component identified by + The diffraction peak is indexed by _twin_refln.index_hkl + referred to the cell of the twin component identified by _twin_refln.individual_id. ; - _name.category_id twin_refln - _name.object_id datum_id - _type.purpose Key - _type.source Assigned - _type.container Single - _type.contents Code + _name.category_id twin_refln + _name.object_id datum_id + _type.purpose Key + _type.source Assigned + _type.container Single + _type.contents Code save_ +save_twin_refln.f_squared_calc -save_twin_refln.F_squared_calc - - _definition.id '_twin_refln.F_squared_calc' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_refln_F_squared_calc' - _description.text + _definition.id '_twin_refln.F_squared_calc' + _alias.definition_id '_twin_refln_F_squared_calc' + _definition.update 2014-06-20 + _description.text ; Calculated value for the overall squared structure factors (in @@ -616,24 +716,21 @@ save_twin_refln.F_squared_calc Reference: Pratt, C. S., Coyle, B. A. & Ibers, J. A. (1971). J. Chem. Soc. A, pp. 2146-2151. ; - _name.category_id twin_refln - _name.object_id F_squared_calc - _type.purpose Measurand - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_refln + _name.object_id F_squared_calc + _type.purpose Measurand + _type.source Derived + _type.container Single + _type.contents Real save_ +save_twin_refln.f_squared_calc_individual -save_twin_refln.F_squared_calc_individual - - _definition.id '_twin_refln.F_squared_calc_individual' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_refln_F_squared_calc_individual' - _description.text + _definition.id '_twin_refln.F_squared_calc_individual' + _alias.definition_id '_twin_refln_F_squared_calc_individual' + _definition.update 2014-06-20 + _description.text ; Contribution of the twin identified by _twin_refln.individual_id @@ -644,135 +741,143 @@ save_twin_refln.F_squared_calc_individual where osf is the overall scale factor, mf is the mass factor. For X-ray diffraction the units are electrons squared. ; - _name.category_id twin_refln - _name.object_id F_squared_calc_individual - _type.purpose Measurand - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_refln + _name.object_id F_squared_calc_individual + _type.purpose Measurand + _type.source Derived + _type.container Single + _type.contents Real save_ +save_twin_refln.f_squared_meas -save_twin_refln.F_squared_meas - - _definition.id '_twin_refln.F_squared_meas' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_refln_F_squared_meas' - _description.text + _definition.id '_twin_refln.F_squared_meas' + _alias.definition_id '_twin_refln_F_squared_meas' + _definition.update 2014-06-20 + _description.text ; The observed value F^2^ of the peak referenced by _twin_refln.datum_id. This is typically the observed peak intensity after Lorentz and polarization corrections. ; - _name.category_id twin_refln - _name.object_id F_squared_meas - _type.purpose Measurand - _type.source Derived - _type.container Single - _type.contents Real + _name.category_id twin_refln + _name.object_id F_squared_meas + _type.purpose Measurand + _type.source Derived + _type.container Single + _type.contents Real save_ +save_twin_refln.f_squared_meas_sigma -save_twin_refln.F_squared_meas_sigma + _definition.id '_twin_refln.F_squared_meas_sigma' - _definition.id '_twin_refln.F_squared_meas_sigma' - _definition.update 2014-07-30 loop_ _alias.definition_id - '_twin_refln_F_squared_meas_sigma' - '_twin_refln_F_squared_sigma' - '_twin_refln.F_squared_sigma' - '_twin_refln.F_squared_meas_su' - _description.text + '_twin_refln_F_squared_meas_sigma' + '_twin_refln_F_squared_sigma' + '_twin_refln.F_squared_sigma' + '_twin_refln.F_squared_meas_su' + + _definition.update 2014-07-30 + _description.text ; Standard uncertainty of _twin_refln_F_squared_meas ; - _name.category_id twin_refln - _name.object_id F_squared_meas_su - _name.linked_item_id '_twin_refln.F_squared_meas' - _type.purpose SU - _type.source Related - _type.container Single - _type.contents Real + _name.category_id twin_refln + _name.object_id F_squared_meas_su + _name.linked_item_id '_twin_refln.F_squared_meas' + _type.purpose SU + _type.source Related + _type.container Single + _type.contents Real save_ - save_twin_refln.include_status - _definition.id '_twin_refln.include_status' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_refln_include_status' - _description.text + _definition.id '_twin_refln.include_status' + _alias.definition_id '_twin_refln_include_status' + _definition.update 2014-06-20 + _description.text ; A symbol indicating how the reflection is treated during refinement. ; - _name.category_id twin_refln - _name.object_id include_status - _type.purpose State - _type.source Assigned - _type.container Single - _type.contents Code + _name.category_id twin_refln + _name.object_id include_status + _type.purpose State + _type.source Assigned + _type.container Single + _type.contents Code + loop_ - _enumeration_set.state - _enumeration_set.detail - o -; (lower-case letter o for 'observed') satisfies _refine_ls.d_res_high - satisfies _refine_ls.d_res_low exceeds _reflns.threshold_expression -; - < -; satisfies _refine_ls.d_res_high satisfies _refine_ls.d_res_low - does not exceed _reflns.threshold_expression -; - - 'systematically absent reflection' - x 'unreliable measurement -- not used' - r 'removed from the refinement for other reasons' - h 'does not satisfy _refine_ls_d_res_high' - l 'does not satisfy _refine_ls_d_res_low' - _enumeration.default o + _enumeration_set.state + _enumeration_set.detail + o +; + (lower-case letter o for 'observed') satisfies _refine_ls.d_res_high + satisfies _refine_ls.d_res_low exceeds _reflns.threshold_expression +; + < +; + satisfies _refine_ls.d_res_high satisfies _refine_ls.d_res_low + does not exceed _reflns.threshold_expression +; + - +; + systematically absent reflection +; + x +; + unreliable measurement -- not used +; + r +; + removed from the refinement for other reasons +; + h +; + does not satisfy _refine_ls_d_res_high +; + l +; + does not satisfy _refine_ls_d_res_low +; -save_ + _enumeration.default o +save_ save_twin_refln.index_h - _definition.id '_twin_refln.index_h' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_refln_index_h' - _description.text + _definition.id '_twin_refln.index_h' + _alias.definition_id '_twin_refln_index_h' + _definition.update 2014-06-20 + _description.text ; Miller index h in the vector _twin_refln.index_hkl. ; - _name.category_id twin_refln - _name.object_id index_h - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Integer + _name.category_id twin_refln + _name.object_id index_h + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Integer save_ - save_twin_refln.index_hkl - _definition.id '_twin_refln.index_hkl' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_refln_index_hkl' - _description.text + _definition.id '_twin_refln.index_hkl' + _alias.definition_id '_twin_refln_index_hkl' + _definition.update 2014-06-20 + _description.text ; Miller index vector of a reflection for the twin component @@ -780,78 +885,67 @@ save_twin_refln.index_hkl The values of the Miller indices must correspond to the cell defined for this twin component. ; - _name.category_id twin_refln - _name.object_id index_hkl - _type.purpose Number - _type.source Derived - _type.container Matrix - _type.contents Integer - _type.dimension '[3]' - loop_ - _method.purpose + _name.category_id twin_refln + _name.object_id index_hkl + _type.purpose Number + _type.source Derived + _type.container Matrix + _type.dimension '[3]' + _type.contents Integer + _method.purpose Evaluation _method.expression - Evaluation ; With t as twin_refln _twin_refln.index_hkl = [t.index_h, t.index_k, t.index_l] -; +; save_ - save_twin_refln.index_k - _definition.id '_twin_refln.index_k' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_refln_index_k' - _description.text + _definition.id '_twin_refln.index_k' + _alias.definition_id '_twin_refln_index_k' + _definition.update 2014-06-20 + _description.text ; - Miller index k in the vector _twin_refln.index_hkl. + Miller index k in the vector _twin_refln.index_hkl. ; - _name.category_id twin_refln - _name.object_id index_k - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Integer + _name.category_id twin_refln + _name.object_id index_k + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Integer save_ - save_twin_refln.index_l - _definition.id '_twin_refln.index_l' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_refln_index_l' - _description.text + _definition.id '_twin_refln.index_l' + _alias.definition_id '_twin_refln_index_l' + _definition.update 2014-06-20 + _description.text ; - Miller index l in the vector _twin_refln.index_hkl. + Miller index l in the vector _twin_refln.index_hkl. ; - _name.category_id twin_refln - _name.object_id index_l - _type.purpose Number - _type.source Derived - _type.container Single - _type.contents Integer + _name.category_id twin_refln + _name.object_id index_l + _type.purpose Number + _type.source Derived + _type.container Single + _type.contents Integer save_ - save_twin_refln.individual_id - _definition.id '_twin_refln.individual_id' - _definition.update 2014-06-20 - loop_ - _alias.definition_id - '_twin_refln_individual_id' - _description.text + _definition.id '_twin_refln.individual_id' + _alias.definition_id '_twin_refln_individual_id' + _definition.update 2014-06-20 + _description.text ; The unique identifier of the twin individual @@ -863,12 +957,98 @@ save_twin_refln.individual_id _twin_refln.individual_id. The combination of these two items may only appear once in a list. ; - _name.category_id twin_refln - _name.object_id individual_id - _name.linked_item_id '_twin.individual_id' - _type.purpose Encode - _type.source Assigned - _type.container Single - _type.contents Code + _name.category_id twin_refln + _name.object_id individual_id + _name.linked_item_id '_twin.individual_id' + _type.purpose Encode + _type.source Assigned + _type.container Single + _type.contents Code save_ + + loop_ + _dictionary_audit.version + _dictionary_audit.date + _dictionary_audit.revision + 1.0 2014-02-14 +; + 2012-07-25 Created from Victor Young's draft text. JRH + 2012-08-20 Added category definitions and corrected _list for + _twin_lattice_type. JRH + 2012-08-21 cosmetic changes such as arranging the items + alphabetically and added queries for VY. I.D.Brown + 2012-08-28 Inserted changes from V. Young as per I.D. Brown's + comments; removed _example_detail for twin category; + corrected _list_reference for _refln_ category; added + explanation for_refln_F_squared_ . JRH + 2012-08-31 Added _twin_special_details with example from VY. JRH + 2013-01-17 Corrected equation defining F_calc. JRH + 2013-01-18 Moved _refln_ items into separate _twin_refln category and + rewrote definitions for clarity. + 2013-03-13 Added missing _twin_refln_index_ . JRH + 2013-03-25 IDB: Added enumeration range to + _twin_individual__mass_fraction_refined and rewrote + the definition + Rewrote the definition of _twin_individual_twin_matrix + Raised queries about what the _twin_refln category + is actually recording. + 2013-05-09 JRH: corrected _twin_refln_F_calc equation; added + _list_reference to _twin_refln_h, *_k, *_l definition; + fiddled with _twin_individual_twin_id definition text + 2013-06-26 JRH,VY: added further example to TWIN category + 2013-06-26 some syntax and formatting errors corrected (BM) + 2013-06-27 IDB Changed _twin_refln_observed_status to + _twin_refln_include_status + Added the twin_contibution category + Reworked the twin_refln category to change the list reference + to _twin_refln_datum_id (name changed from _*_datum_index + Made some improvements to the definitions. + Converted space group symbols to CIF conventions + Arranged items in alphabetic order to conform + to other dictonaries. + 2013-07-11 JRH edited examples to reflect proposed changes from IDB + 2013-07-29 VGY modified examples to comply with IDB's suggested changes + (see below). These are within comments, but not yet + integrated into the text of the document. Added nmt for + non-merohedral twin into data_twin_lattice_type. Somehow + this was removed. + 2013-08-16 VGY made corrections as directed by JH in examples 2 and 3. + Removed work for these examples from commented text and + integrated into document. Updated example 1 to include + explicit _twin_contribution items for individual 2. + 2013-09-02 JRH edited in latest examples from VGY after email discussion + 2013-09-03 JRH: move lattice_twin_type into twin_individual category; + add 'ref' lattice twin type. Changed + _twin_contribution_twin_id to + _twin_contribution_individual_id + 2013-09-03 VGY: improve example to include single-contributor + reflections coming from different individuals. + 2013-09-13 IDB: Changed _refln_twin to _twin_refln, + improved wording of some definitions, corrected syntax + errors, added _twin_refln_include_status, + removed '_mandatory yes' from _twin_refln_index_ + Rearranged the order of items in some examples to put the + list reference first. + 2013-11-13 IDB: Following comments from Tony Linden and George Sheldrick + an alternative version of twin_refln is proposed. + If this is adopted _twin_contribution would be dropped. + 2013-12-04 IDB: The alternative twin_refln is adopted and + twin_contribution is deleted. + 2012-12-04 Minor spelling corrections,removal of old twin_contribution + material and example clarification added. VGY + 2012-12-05 IDB: Made changes in the description of the example + under the twin category to reflect the deletion + of the twin_contribution category. + Removed '_twin_contribution_individual_id' from + _link_list_child in the definition of _twin_individual_id. + Modified the description of the twin_refln category + to reflect the merging of twin_contribution with twin_refln. + Added r to enumeration list of _twin_refln_include_status. + 2014-02-14 BMcM and NJA: minor editing for clean release version +; + 3.1 2024-11-21 +; + 2014-06-20 Converted to DDLm (SRH/JRH) + 2024-11-21 Examples and history returned to main dictionary (JRH) +; diff --git a/cif_twin.examples b/cif_twin.examples deleted file mode 100644 index 7a72099..0000000 --- a/cif_twin.examples +++ /dev/null @@ -1,193 +0,0 @@ -############################################################################## -# # -# CIF Twinning Definitions # -# # -# This dictionary contains names and definitions of twinning data items # -# recognized by the International Union of Crystallography for the exchange # -# of data between laboratories and submissions to journals and databases. # -# # -# The STAR/DDL dictionary to which this dictionary conforms # -# is available as the file "ddl_core.dic" # -# located at URL ftp://ftp.iucr.org/pub/cifdics/ddl_core_1.4.1.dic # -# # -############################################################################## - -############### -## TWIN ## -############### - - -# ----------------------------------------------------------------------------- -# Example -; - _twin_formation_mechanism gt - _twin_dimensionality triperiodic - _twin_morphology polysynthetic - _twin_special_details - ; This is an example of a twin in space group P 32 - by the 2 x,x,0 twin operation. - ; - - loop_ - _twin_individual_id - _twin_individual_mass_fraction_refined - _twin_individual_twin_lattice_type - _twin_individual_twin_matrix_11 - _twin_individual_twin_matrix_12 - _twin_individual_twin_matrix_13 - _twin_individual_twin_matrix_21 - _twin_individual_twin_matrix_22 - _twin_individual_twin_matrix_23 - _twin_individual_twin_matrix_31 - _twin_individual_twin_matrix_32 - _twin_individual_twin_matrix_33 - 1 0.545(2) ref 1 0 0 0 1 0 0 0 1 - 2 0.455(2) mt_II 0 1 0 1 0 0 0 0 -1 - - loop_ - _twin_refln_datum_id - _twin_refln_individual_id - _twin_refln_index_h - _twin_refln_index_k - _twin_refln_index_l - _twin_refln_F_squared_calc - _twin_refln_F_squared_meas - _twin_refln_F_squared_sigma - _twin_refln_include_status - 1 1 -1 1 -32 40.17 55.86 7.39 o - 1 2 1 -1 32 40.17 55.86 7.39 o - 2 1 0 1 -32 125.83 145.63 9.36 o - 2 2 1 0 32 125.83 145.63 9.36 o - 3 1 1 1 -32 10.33 30.89 7.39 o - 3 2 1 1 32 10.33 30.89 7.39 o - 4 1 -3 2 -32 28.26 26.84 9.47 o - 4 2 2 -3 32 28.26 26.84 9.47 o - 5 1 -2 2 -32 4.31 13.21 9.78 o - 5 2 2 -2 32 4.31 13.21 9.78 o - 6 1 -1 2 -32 10.71 17.48 9.88 o - 6 2 2 -1 32 10.71 17.48 9.88 o - 7 1 0 2 -32 13.94 37.66 10.51 o - 7 2 2 0 32 13.94 37.66 10.51 o - 8 1 1 2 -32 58.60 75.41 9.88 o - 8 2 2 1 32 58.60 75.41 9.88 o - 9 1 -2 3 -32 27.75 41.40 8.01 o - 9 2 3 -2 32 27.75 41.40 8.01 o - 10 1 -1 3 -32 59.22 65.53 8.11 o - 10 2 3 -1 32 59.22 65.53 8.11 o - -; -# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _example_detail -; - The twinning example presented here shows twinning by merohedry for - a trigonal crystal system. The simulated space group is P 32 2 1, but - the true space group is P 32. The twin operation chosen is 2: x, x, 0 in - P 32 2 1 corresponding to operation (by rows) 0, 1, 0 / 1, 0, 0 / 0, 0, -1 - [see Table 11.2.2.1 of International Tables for Crystallography - (2005), Vol. A]. - - The TWIN_REFLN loop gives the properties of each diffraction peak - (identified by _twin_refln_datum_id) which is indexed - to both the twin individuals. - - In each of the loops shown in this example the first items on a line - are the list reference. While the list reference must be present - in every loop, it is not necessary that it should be declared as the -first item in the loop. -; - - -########################## -## TWIN_INDIVIDUAL ## -########################## - - -################ -## TWIN_REFLN ## -################ - - -# - Example 1 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -; - loop_ - _twin_refln_datum_id - _twin_refln_individual_id - _twin_refln_index_h - _twin_refln_index_k - _twin_refln_index_l - _twin_refln_F_squared_meas - _twin_refln_F_squared_sigma - _twin_refln_include_status - - 1 1 1 0 0 1.03 0.18 o - 1 3 1 0 0 1.03 0.18 o - 2 1 2 0 0 1290.01 55.59 o - 2 3 2 0 0 1290.01 55.59 o - 3 1 3 0 0 2.59 0.42 o - 3 3 3 0 0 2.59 0.42 o - 4 1 4 0 0 30.98 1.47 o - 4 3 4 0 0 30.98 1.47 o - 5 1 5 0 0 1.97 0.96 o - 5 3 5 0 0 1.97 0.96 o - 6 1 6 0 0 1.55 1.14 o - 6 2 6 1 2 1.55 1.14 o - 6 3 6 0 0 1.55 1.14 o - 6 4 6 1 2 1.55 1.14 o - 7 1 -6 1 0 0.47 1.06 o - 7 2 6 2 2 0.47 1.06 o -; -#--------------------------------------------------------------------- - -# Description of Example 1 -; - This partial listing describes seven observed diffraction peaks - in a four-individual twin by non-merohedry. The reference individual - is 1. Reflections from the other three individuals 2, 3 and 4 are - present only if these cannot be experimentally separated from the - reference individual. -; - -# ---- Example 2 ------------------------------------------------------ -; - loop_ - _twin_refln_datum_id - _twin_refln_individual_id - _twin_refln_index_h - _twin_refln_index_k - _twin_refln_index_l - _twin_refln_F_squared_calc - _twin_refln_F_squared_meas - _twin_refln_F_squared_sigma - _twin_refln_include_status - - 620 1 1 -6 -3 200.22 207.88 3.35 o - 621 1 -1 6 3 225.34 224.15 3.62 o - 622 2 -1 6 3 184.64 196.34 3.95 o - 623 1 -1 -6 -3 173.28 181.13 3.06 o - 624 2 -1 -6 -3 143.40 152.05 2.78 o - 625 1 1 6 3 204.45 204.38 4.48 o - 625 2 3 -6 1 204.45 204.38 4.48 o - 626 1 3 -6 -3 240.97 241.19 3.75 o - 626 2 -3 6 3 240.97 241.19 3.75 o - 627 1 3 6 3 288.54 281.53 4.31 o - 627 2 -3 -6 -3 288.54 281.53 4.31 o - 628 1 -5 -6 -3 179.56 176.35 5.36 o - 628 2 -3 6 5 179.56 176.35 5.36 o - 629 1 5 6 3 235.04 238.84 4.06 o - 629 2 -5 -6 -3 235.04 238.84 4.06 o -; -# -------------------------------------------------------------------- -; - This example is taken from Colombo Young & Gladfelter - [Inorg. Chem. (2000), 39, 4621-4624]. - Two structures of nitronium tetranitratogallate - are reported as a result of an enantiotropic phase transition. - The higher-temperature phase is in the tetragonal space group I-4, - while the lower-temperature phase is a twin by non-merohedry - in space group I2. - The individuals are enantiomorphic as a result of the phase transition. - In the listing it is clear that datums 620-624 do not contain - overlapping reflections, whereas datums 625-629 contain contributions - from both twins. -; - diff --git a/cif_twin.history b/cif_twin.history deleted file mode 100644 index 34a6d26..0000000 --- a/cif_twin.history +++ /dev/null @@ -1,95 +0,0 @@ -############################################################################## -# # -# History of CIF Twinning Definition Revisions # -# # -# This dictionary contains names and definitions of twinning data items # -# recognized by the International Union of Crystallography for the exchange # -# of data between laboratories and submissions to journals and databases. # -# # -# The STAR/DDL dictionary to which this dictionary conforms # -# is available as the file "ddl_core.dic" # -# located at URL ftp://ftp.iucr.org/pub/cifdics/ddl_core_1.4.1.dic # -# # -############################################################################## - - loop_ - _dictionary_audit.version - _dictionary_audit.date - _dictionary_audit.revision - - - 1.0 2014-02-14 -; - 2012-07-25 Created from Victor Young's draft text. JRH - 2012-08-20 Added category definitions and corrected _list for - _twin_lattice_type. JRH - 2012-08-21 cosmetic changes such as arranging the items - alphabetically and added queries for VY. I.D.Brown - 2012-08-28 Inserted changes from V. Young as per I.D. Brown's - comments; removed _example_detail for twin category; corrected - _list_reference for _refln_ category; added explanation for - _refln_F_squared_ . JRH - 2012-08-31 Added _twin_special_details with example from VY. JRH - 2013-01-17 Corrected equation defining F_calc. JRH - 2013-01-18 Moved _refln_ items into separate _twin_refln category and - rewrote definitions for clarity. - 2013-03-13 Added missing _twin_refln_index_ . JRH - 2013-03-25 IDB: Added enumeration range to - _twin_individual__mass_fraction_refined and rewrote - the definition - Rewrote the definition of _twin_individual_twin_matrix - Raised queries about what the _twin_refln category - is actually recording. - 2013-05-09 JRH: corrected _twin_refln_F_calc equation; added - _list_reference to _twin_refln_h, *_k, *_l definition; - fiddled with _twin_individual_twin_id definition text - 2013-06-26 JRH,VY: added further example to TWIN category - 2013-06-26 some syntax and formatting errors corrected (BM) - 2013-06-27 IDB Changed _twin_refln_observed_status to - _twin_refln_include_status - Added the twin_contibution category - Reworked the twin_refln category to change the list reference - to _twin_refln_datum_id (name changed from _*_datum_index - Made some improvements to the definitions. - Converted space group symbols to CIF conventions - Arranged items in alphabetic order to conform - to other dictonaries. - 2013-07-11 JRH edited examples to reflect proposed changes from IDB - 2013-07-29 VGY modified examples to comply with IDB's suggested changes - (see below). These are within comments, but not yet integrated - into the text of the document. Added nmt for non-merohedral - twin into data_twin_lattice_type. Somehow this was removed. - 2013-08-16 VGY made corrections as directed by JH in examples 2 and 3. - Removed work for these examples from commented text and - integrated into document. Updated example 1 to include explicit - _twin_contribution items for individual 2. - 2013-09-02 JRH edited in latest examples from VGY after email discussion - 2013-09-03 JRH: move lattice_twin_type into twin_individual category; add - 'ref' lattice twin type. Changed _twin_contribution_twin_id to - _twin_contribution_individual_id - 2013-09-03 VGY: improve example to include single-contributor reflections - coming from different individuals. - 2013-09-13 IDB: Changed _refln_twin to _twin_refln, - improved wording of some definitions, corrected syntax errors, - added _twin_refln_include_status, - removed '_mandatory yes' from _twin_refln_index_ - Rearranged the order of items in some examples to put the - list reference first. - 2013-11-13 IDB: Following comments from Tony Linden and George Sheldrick - an alternative version of twin_refln is proposed. - If this is adopted _twin_contribution would be dropped. - 2013-12-04 IDB: The alternative twin_refln is adopted and - twin_contribution is deleted. - 2012-12-04 Minor spelling corrections,removal of old twin_contribution - material and example clarification added. VGY - 2012-12-05 IDB: Made changes in the description of the example - under the twin category to reflect the deletion - of the twin_contribution category. - Removed '_twin_contribution_individual_id' from - _link_list_child in the definition of _twin_individual_id. - Modified the description of the twin_refln category - to reflect the merging of twin_contribution with twin_refln. - Added r to enumeration list of _twin_refln_include_status. - 2014-02-14 BMcM and NJA: minor editing for clean release version -; -