Core CIF Dictionary version 2.3

    	


   1991-05-27  Created from CIF Dictionary text. SRH
   1991-05-30  Validated with CYCLOPS & CIF ms. SRH
   1991-06-03  Adjustments to some definitions. SRH
   1991-06-06  Adjustments a la B. McMahon. SRH
   1991-06-18  Additions & some redefinitions. SRH
   1991-07-04  Corrected 90:0 in *_detect_slit_. SRH
   1991-09-20  Additions & some redefinitions. SRH
   1991-09-20  Final published version. IUCr
   1991-11-12  Add _diffrn_ambient_environment. SRH
   1991-11-12  Allow 'c' for _atom_site_calc_flag. SRH
   1993-02-23  Apply global_ and 'unknown' -> '?' SRH
   1993-03-05  Changes resulting from MM dictionary. SRH
   1993-05-20  Changes arising from new DDL commands. SRH
   1993-08-05  Additional finetuning pre-Beijing. SRH
   1993-12-22  Introductory sections added to categories. BMcM
   1993-12-22  Additional categories from mm work: audit_author,
                 citation, atom_sites_fract_tran_matrix. BMcM
   1994-03-01  Add 'undef' to _refine_ls_hydrogen_treatment. BMcM
   1994-03-01  Add '_publ_section_exptl_prep' and '*_refinement'. BMcM
   1994-03-01  Add 'atom_site_aniso_ratio'. BMcM
   1994-04-15  Comments from IDB on draft version for circulation. BMcM
   1994-04-15  Added _publ_section_exptl_solution. BMcM
   1994-07-14  Added B. H. Toby's suggested _diffrn_radiation_xray_symbol
                 and _diffrn_radiation_xray_target. BMcM
   1994-08-05  Revised definition for _diffrn_reflns_number (S.R. Hall). BMcM
   1994-08-05  Added _atom_type_scat_length_neutron (B.H. Toby). BMcM
   1994-10-13  Reworded _diffrn_standards_ a la S.R. Hall. BMcM
   1994-10-13  Added _diffrn_radiation_probe for non-X-ray experiments. BMcM
   1995-01-17  Rewording of definition of _chemical_melting_point. BMcM
   1995-02-24  Changed text references to e.s.d to 'standard uncertainty'. BMcM
   1995-07-08  Added _chemical_formula_iupac. BMcM
   1995-07-09  Finally added _symmetry_equiv_pos_id. BMcM
   1995-07-09  _units_extension, _units_conversion and _units_description
                 superseded by _units and _units_detail. Suffixed datanames
                 retained as separate entries. BMcM
   1995-10-23  Added _refine_ls_R_Fsqd_factor and _refine_ls_R_I_factor BMcM
   1996-03-25  Correlated with mmCIF release 0.8 BMcM
   1996-05-16  Added some extra datanames for use by Acta:
                 _publ_section_synopsis, _publ_section_title_footnote,
                 _publ_author_footnote, _journal_paper_category, and various
                 _journal_index_ categories BMcM
   1996-05-20  Added geom_hbond category BMcM
   1996-06-10  Datanames with suffixes to indicate units moved to a new
                 compatibility dictionary cif_compat.dic BMcM
   1996-06-10  Embarrassing _units_ stuff removed from geom_hbond BMcM
   1996-06-10  _list_mandatory and _list_reference added to _publ_author_
                 datanames (where _list was given as "both") BMcM
   1996-06-10  Added audit_conform category BMcM
   1996-06-11  Added audit_link category BMcM
   1996-06-11  Reworded _exptl_crystal_F_000 definition BMcM
   1996-06-11  Added _atom_site_U_equiv_geom BMcM
   1996-06-11  Added publ_body category BMcM
   1996-06-27  Added examples for most of the remaining category overviews
                 BMcM
   1996-06-27  Added _journal_language BMcM
   1996-06-28  Added area-detector definitions from mmCIF dictionary:
                 _diffrn_measurement_device_details, *_specific and *_type;
                 _diffrn_radiation_detector_details, *_specific, *_type;
                 _diffrn_radiation_source_details, *_power, *_specific,
                 *_target, *_type; reflns_shell category  BMcM
               Added _refine_ls_d_res_high and *_low and changed wording of
                 definitions for R factors to include these. BMcM
               Added 'h' and 'f' flags to _refln_observed_status. BMcM
   1996-07-05  Some typos fixed and examples modified as suggested by
                 P.Strickland and I.D.Brown. BMcM
   1996-07-27  BMcM:
               Added example for _diffrn_orient_refln_[] from G. Madariaga
               U~ij~ changed to U^ij^ a la Nomenclature Commission
               Definition of _diffrn_ambient_environment changed to omit vacuum
                 as a possible default environment
               Changed definitions of *_site_symmetry_* items to I.D.Brown's
                 suggested wording.
               Compressed various journal indexing categories into one
               Changed upper enumeration values for _refln_symmetry_epsilon
                 and _refln_symmetry_multiplicity to 48.
               Added references to deprecated use of B values.
               Modified descriptions of phone, fax number conventions
               _publ_manuscript_incl_ entries reworded for greater
                 clarity and given individual data blocks
               Added _list_reference to _symmetry_equiv_pos_id and changed
                 _list value to 'both' for *_as_xyz to allow the P1 case
               Added _atom_site_B_equiv_geom for completeness
               Modified definitions of _atom_sites_[Cartn,fract]_tran_vector_
               Added _units stuff to _chemical_formula_weight_* and
                 _exptl_crystal_density_ items
               Added *_theta, *_omega to _diffrn_orient_refln_angle_
               Added 'q' to enumeration list for _diffrn_refln_scan_mode
               Reworded definition in _diffrn_scale_group_[]
               Permitted esd for _refln_phase_meas (necessitates splitting
                 _refln_phase_ datablock in two)
               Added _type_conditions esd for _reflns_scale_meas_
   1996-07-28  BMcM:
               Added example for refln_scale_[] and second example for
                 _refln_[] from Xtal test data set.
               Changed references to category names to CAPITALS.
               Merged CELL and CELL_MEASUREMENT categories.
               Added _units deg to all angle quantities.
               Renamed _citation_journal_coden_CAS as
                 _citation_journal_abstract_id_CAS
               Removed _diffrn_measurement_device_details, *_specific,
                 *_type, _diffrn_radiation_detector_details, *_specific,
                 *_type, _diffrn_radiation_source_power, *_specific,
                 *_target, *_type, pending full analysis of requirements
                 for describing diffraction apparatus.
               Reworded _exptl_crystal_F_000 definition again
   1996-08-03  Reworded _refine_ls_number_reflns definition a la S.R.Hall BMcM
   1996-09-10  BMcM:
               Clarified _diffrn_attenuator_scale definition with help from SRH
               In _refln_symmetry_multiplicity, changed 'structure-factor
                 value' to 'structure-factor magnitudes'
               Slight modification to _diffrn_reflns_number to exclude all
                 systematic absences, not just those due to centring
               Removed footnote markers from example of
                 _publ_section_title_footnote
               Added new example to SYMMETRY_EQUIV category to explain the
                 use of _symmetry_equiv_pos_id
               Reworking of DIFFRN_RADIATION and DIFFRN_MEASUREMENT
                 categories and introduction of DIFFRN_DETECTOR and
                 DIFFRN_SOURCE a la I.D.Brown
   1996-09-11  Corrected category assignment for _diffrn_standards_ items BMcM
   1996-09-12  BMcM:
               Added _cell_id and _cell_measurement_refln_id
               Changed the term "id" to "identifier" in definitions
               Renamed _citation_journal_abstract_id_CAS as
                 _citation_abstract_id_CAS
               Added _audit_block_code and changed definition of
                  _audit_link_block_code to refer to it
   1996-09-18  BMcM:
               Fine tuning of IDB's new DIFFRN categories: in DIFFRN_DETECTOR
                 changed *_type to *_device and added *_device_type. Moved
                 _diffrn_radiation_detector back to DIFFRN_RADIATION category
                 with expanded definition. Reworded definitions of
                 _diffrn_measurement_device and *_device_type. In
                 DIFFRN_RADIATION changed enumeration range for
                 *_polarisn_norm to -180:180 and added 'as viewed from the
                 specimen' to the definition; also added 'Cu K-L~2,3~' to
                 examples for *_type. Reworded definitions for
                 _diffrn_refln_index and _diffrn_source_target, and changed
                 _type of _diffrn_source_power to "numb".
               Introduced _diffrn_detector_dtime in the DIFFRN_DETECTOR
                 category and restored _diffrn_radiation_detector_dtime to
                 DIFFRN_RADIATION
   1996-09-25  BMcM:
               Reworded definitions of _atom_site_disorder_assembly and *_group
   1996-10-02  BMcM:
               Changed _symmetry_equiv_pos_id to _symmetry_equiv_pos_site_id
                 in recognition of the technical meaning of 'position' in
                 International Tables
               Addition of the names of the relevant units to definitions of
                 _atom_type_scat_length_neutron, _exptl_crystal_size_,
                 _geom_hbond_distance_, _refine_ls_d_res_high and *_low,
                 _reflns_shell_d_res_high and *_low; and cosmetic expansion
                 of units listed in the definitions for _diffrn_source_current,
                 *_power and *_voltage
               Addition of '_related_function conversion' to
                 _atom_site_B_equiv_geom and *_U_equiv_geom and
                 _atom_site_B_iso_or_equiv and *_U_iso_or_equiv
               Examples for CELL_MEASUREMENT_REFLN and DIFFRN_REFLN from
                 Gotzon Madariaga
               Renamed _atom_site_U_equiv_geom as _atom_site_U_equiv_geom_mean
                 and likewise for *_B_* to increase the consistency of
                 abbreviations, as suggested by I.D. Brown
               Added disorder example to the ATOM_SITE category description
   1996-10-15  BMcM:
               Modified description of example for DIFFRN_REFLN
               Changed _enumeration_range of _atom_site_attached_hydrogens
                 from 0:4 to 0:8 (cf CSD entry with refcode DUTMAG01) (PRE)
               Added '_enumeration_default cif' to _publ_body_format
               Changed underscores to spaces in the example for the Hall
                 spacegroup symbol in data_symmetry_[]
               Deleted extraneous '_' in data_(_)citation_abstract_id_CAS
   1996-10-27  BMcM: Changed psiscan to psi-scan at request of SRH
   1996-11-05  BMcM:
               Changed _citation_book_coden_ISBN to _citation_book_id_ISBN,
                 _citation_journal_coden_ASTM to _citation_journal_id_ASTM,
                 _citation_journal_coden_CSD to _citation_journal_id_CSD,
                 _citation_journal_coden_ISSN to _citation_journal_id_ISSN,
                 and _citation_Medline_AN to _citation_database_id_Medline.
                 Also modified description of CODEN in _citation_journal_id_ASTM
                 and _database_journal_ASTM (suggested by PMDF)
               The phrase 'diffraction data' modified to 'intensities' in
                 several places, some other cosmetic commas and enforcement
                 of consistent lower-case units names (PMDF)
               Clarification of the definition for
                 _diffrn_radiation_polarisn_norm (PMDF)
               Added 'constr' to _refine_ls_hydrogen_treatment (SRH)
               Corrected misassignment of category of
                 _diffrn_radiation_detector_dtime (H.J.Bernstein)
   1996-11-06  BMcM:
               Added "_list   yes" to items in the REFLNS_SHELL category (IDB)
               Added "measured" to definition of _reflns_shell_number_unique_all
               Changed enumeration range for _diffrn_standards_decay_% to
                 ":100" and added statement about negative values (PMDF/SRH)
   1996-11-08  BMcM:
               _diffrn_radiation_detector, _diffrn_radiation_detector_dtime and
                 _diffrn_radiation_source removed (these will be transferred to
                 cif_compat.dic for compatibility with files conforming to the
                 original dictionary)
               _diffrn_radiation_wavelength_* items moved to new category
   1996-11-12  BMcM:
               Deleted _cell_id and _cell_measurement_refln_id, and
                 clarified the intent of the CELL category in _cell_[] (PMDF)
               Some small rewordings of various _diffrn_* items due to
                 B.H.Toby
   1996-11-14  BMcM:
               Imposed consistency on the nomenclature of diffraction device
                 data names: _diffrn_detector_device_type -> *_detector_type,
                 _diffrn_measurement_device_details -> *_measurement_details,
                 *_measurement_device_type -> *_measurement_type; introduction
                 of _diffrn_source_device and parallel definitions. Existing
                 *_measurement_details example moved to *_special_details (PMDF)
   1996-11-21  BMcM:
               Reintroduced _diffrn_measurement_device_details, further tidying
                 of data names thus: _diffrn_measurement_type -> *_device_type;
                 _diffrn_detector_device and _diffrn_source_device both drop
                 "_device" (PMDF)
               Added _journal_data_validation_number and
                 _publ_requested_category to enable handling of CIF-access
                 submissions by Acta Cryst. C
   1996-11-23  A few typos fixed. BMcM
   1996-11-24  BMcM:
               Added 'gaussian', 'multi-scan' and 'numerical' to enumeration
                 list for _exptl_absorpt_correction_type (SRH)
               Added 'mixed' to enumeration list for
                 _refine_ls_hydrogen_treatment (SRH)
   1996-11-25  A few typos fixed (BMcM)
   1996-11-27  BMcM:
               Removed looped _related_item from _publ_contact_author and
                 reintroduced _diffrn_radiation_detector, *_dtime and
                 _diffrn_radiation_source (see 1996-11-08) with
                 "_related_function replace" as a preparation for
                 using this mechanism further in version 2.1.
   1996-11-27  Release version 2.0. IUCr
   1997-01-20  BMcM:
               Some small changes thanks to PMDF. Double space after period
                 at end of sentence changed to single space throughout;
                 _citation_database_id_Medline _diffrn_detector_type moved
                 to correct alphabetic sequence; space introduced between
                 sentences in definition of _citation_journal_id_CSD; some
                 other minor grammatical changes
   1997-10-30  BMcM: (changes to align with Acta C Notes for Authors)
               Obsoleted *_obs_* entries in REFLNS and REFINE_LS categories
                 and replaced with *_gt_*; obsoleted _refine_ls_shift/esd_
                 by _refine_ls_shift/su_; obsoleted
                 _atom_site_thermal_displace_type by *_adp_type
   1997-11-05  BMcM: (changes to align with Acta C Notes for Authors)
               Added _diffrn_detector_area_resol_mean,
                 _diffrn_measured_fraction_theta_max and *_full,
                 _diffrn_reflns_theta_full
   1997-11-05  BMcM: Added _reflns_number_Friedel; changed various *_obs
                 items in examples to *_gt equivalents and likewise for
                 other obsoleted items
   1997-11-24  BMcM: Slightly changed wording of _reflns_number_Friedel and
                 _reflns_threshold_expression at suggestion of I.D.Brown.
                 Modified definition of _refine_ls_abs_structure_Flack and
                 changed the text of the example in category REFINE at
                 the request of H.D.Flack.
   1997-12-08  BMcM: Removed the phrase "(enantiomorph or polarity)" from
                 _refine_ls_abs_structure_Flack and *_Rogers because
                 "absolute structure" is a phrase uniquely defined (H.D.Flack)
   1997-12-08  BMcM: Several instances of \s changed to u
   1997-12-08  BMcM: Modified definitions of _reflns_number_total and
                 *_Friedel (after H.D.Flack) to clarify the distinction between
                 crystal-class and Laue-symmetry independent reflection sets
   1997-12-08  BMcM: Added _chemical_absolute_configuration and
                  _chemical_optical_rotation (H.D.Flack)
   1998-08-04  BMcM: Moved _diffrn_pressure_history and _diffrn_thermal_history
                  from draft msCIF dictionary to core as
                  _exptl_crystal_pressure_history and
                  _exptl_crystal_thermal_history (G. Madariaga/I.D.Brown)
                    Moved _diffrn_symmetry_description and REFINE_LS_CLASS
                  from draft msCIF dictionary to core (G. Madariaga/I.D.Brown)
   1998-08-04  BMcM: Minor rewordings of _refine_ls_R_Fsqd_factor,
                  _refine_ls_R_I_factor, various definitions referring to
                  F_calc in electrons, and _reflns_shell_number_unique_*
                  (I.D.Brown)
   1998-08-04  BMcM: added _reflns_Friedel_coverage (H.D.Flack/S.R.Hall)
   1998-08-04  BMcM: changed formula for F(000) (from
                  F(000) = [ sum (f~r~^2^ + f~i~^2^) ]^1/2^     to
                  F(000) = [ (sum f~r~)^2^ + (sum f~i~)^2^ ]^1/2^ ) (H.D.Flack)
   1998-08-04  BMcM: added 'syn' and 'unk' as enumerations to
                  _chemical_absolute_configuration (H.D.Flack/A.Linden)
   1998-09-02  BMcM: added _exptl_crystal_size_length and modified slightly
                  the definition of _exptl_crystal_size_ (W.Clegg/I.D.Brown)
                    Added _diffrn_attenuator_material (I.D.Brown)
                    Added sentence explaining the physical meaning of the
                  _enumeration_range to _refine_ls_abs_structure_Flack
                  (H.D.Flack)
                    Some rewording in _chemical_absolute_configuration implying
                  that for absolute configuration determination the measurement
                  and reporting of the optical rotation in solution are
                  considered mandatory. (H.D.Flack)
                    Some rewording in _reflns_number_total and *_gt to clarify
                  the inclusion of Friedel reflections; addition of
                  _reflns_Friedel_coverage; deletion of _reflns_number_Friedel
                  (H.D.Flack/S.R.Hall)
                    Further minor rewording to _reflns_shell_number_unique_all,
                  *_gt, *_obs (H.D.Flack)
   1998-09-10  BMcM: transferred _diffrn_reflns_number_of_classes and the
                  categories DIFFRN_REFLNS_CLASS, REFLNS_CLASS and
                  REFLNS_SHELL_CLASS from the draft msCIF dictionary; added
                  _diffrn_refln_class_code and _refln_class_code to link
                  individual reflections to their related categories.
   1998-12-08  BMcM: implemented H.D. Flack's reworking of DIFFRN_REFLNS_CLASS,
                  REFLNS_CLASS, REFLNS_SHELL_CLASS and REFINE_LS_CLASS, deleting
                  the latter two; removed _diffrn_reflns_number_of_classes.
   1998-12-15  BMcM: completed the above reworking; fixed embarrassing typo for
                  _related_function
   1999-01-16  BMcM: coreDMG review of version 2.1beta5. Numerous small changes
                  from I.D.Brown, the most significant being:
                   _atom_site_occupancy definition clarifies how to impose an
                    experimental uncertainty on the _enumeration_range;
                   _atom_site_U_iso_or_equiv enumeration range set to infinity;
                   _atom_type_analytical_mass_% enumeration range set as 0:100;
                   expanded definitions of _diffrn_radiation_probe and *_type to
                    clarify the distinction between these two items;
                   added reference to _exptl_crystal_size to the definition of
                    _exptl_crystal_description, and modified the definition of
                    _exptl_crystal_face_diffr_ ;
                   new data item _refln_d_spacing;
                   clarified the role of _reflns_special_details in specifying
                    whether Friedel pairs have been averaged;
                  Numerous small changes from H.D.Flack, most significantly:
                   removed enumeration range from _diffrn_refln_counts_ because
                    *_net can go negative;
                   fixed various typos in equations for wR and S;
                   removed reference to Friedel reflections from
                    _refln_symmetry_multiplicity
   1999-01-24  BMcM: further revision to wording of _refln_symmetry_multiplicity
                   following discussions by HDF and IDB
                  Numerous small changes from G.Madariaga, most significantly:
                   a instead of A for real-space cell lengths
                    (_atom_site_B_iso_or_equiv and _atom_site_U_iso_or_equiv);
                   _related_function alternate for _atom_site_Cartn_ & _fract_;
                   "or scattering lengths" added to _atom_type_scat_source;
                   deleted incorrect _list_reference in DIFFRN_RADIATION;
                   added rtf to enumeration in _publ_body_format;
                   added enumeration range to _refine_ls_abs_structure_Rogers
   1999-02-04  BMcM: fixed some long lines
   1999-02-06  BMcM: data names using sigma as an indicator of experimental
                     standard uncertainty replaced by equivalents using the
                     preferred 'u' notation (HDF):
                          _diffrn_refln_intensity_sigma
                          _diffrn_reflns_av_sigmaI/netI
                          _diffrn_reflns_class_av_sgI/I
                          _diffrn_standards_scale_sigma
                          _reflns_shell_meanI_over_sigI_all
                          _reflns_shell_meanI_over_sigI_gt
                 (_reflns_shell_meanI_over_sigI_obs already replaced by *_gt)
                   addition of '_related function alternate' to new data
                     items corresponding to old items with
                     '_related_function replace' (SRH)
                   Example for _citation_journal_id_CSD changed to 0070 to
                     reflect current practice at PDB (F.C.Bernstein)
                   Added _atom_type_scat_dispersion_source (GM)
   1999-03-24  Some minor cosmetic modifications (BMcM)
   1999-03-24  Release version 2.1. IUCr
   2001-01-09  BMcM: simplified entry for _chemical_absolute_configuration
                     (H.D.Flack)
                     Added _geom_bond_valence and the new categories
                     VALENCE_PARAM and VALENCE_REF (I.D.Brown)
   2001-01-11  BMcM: Categories EI, EO, EM added to _publ_requested_category
   2001-01-11  Release version 2.2. IUCr
   2003-09-28  BMcM: incorporated changes approved by COMCIFS following
                     discussions of the core Dictionary Management Group:
               _atom_site_fract_ nonsense enumeration default value removed
               _atom_site_refinement_flags deprecated in favour of new
                     *_flags_posn, *_adp and *_occupancy items
               _atom_sites_special_details added
               _cell_reciprocal_angle_ and *_length_ added
               '_type_conditions esd' added to _chemical_melting_point
               _chemical_melting_point_gt and *_lt added
               Added several new items describing chemical properties to
                     the CHEMICAL category: _chemical_properties_biological and
                     *_physical, _chemical_temperature_decomposition_* and
                     *_sublimation_*, at the request of CCDC
               _citation_database_id_CSD added at request of CCDC
               Several additional tags storing deposition numbers of
                     database entries and record revision history at
                     request of CCDC: _database_code_depnum_ccdc_fiz,
                     *_journal, *_archive and _database_CSD_history
               Added _diffrn_ambient_pressure_gt,lt and *_temperature_gt,lt
               Added _diffrn_source_take-off_angle
               Added _diffrn_standards_decay_%_lt
               _diffrn_reflns_measured_fraction_resolution_full and *_max
                     introduced as replacements for
                     _diffrn_measured_fraction_theta_full and *_max, moved
                     to a more appropriate category and defined in terms
                     of resolution rather than angle which depends on the
                     radiation used.
               Likewise for _diffrn_reflns_resolution_full and *_max as
                     replacements for _diffrn_reflns_theta_full and *_max
               More specific parsable tags for crystal colour introduced as
                     _exptl_crystal_colour_primary, *_modifier and *_lustre
               Added _exptl_crystal_density_meas_gt,lt and *_meas_temp_gt,lt
               Added _exptl_crystal_recrystallization_method
               Added _publ_contact_author_id_iucr and _publ_author_id_iucr
                     to allow unique author identification by IUCr database
                     reference identifier
               More datanames for recording imprecise quantities:
                     _refine_ls_shift/su_max_lt and _refine_ls_shift/su_mean_lt
               Added the categories SPACE_GROUP and SPACE_GROUP_SYMOP
                     as imports from the symmetry dictionary cif_sym.dic
               Added _related_function 'replace' to a number of items in
                     the old SYMMETRY category pointing to the preferred
                     items from the new SPACE_GROUP category
   2003-08-19  BMcM: formal approval for COMCIFS for the additions and
                     contingent changes discussed on the coreDMG discussion
                     list from June 2002
   2003-09-29  BMcM: second round of changes from coreDMG discussions:
               Added _enumeration_range to new _chemical_temperature_* items;
               Expanded definition of _space_group_symop_operation_xyz to
                     make explicit the need for inclusion of centring
                     translations (HDF/IDB)
               Removed _diffrn_reflns_measured_fraction_resolution_full and
                     *_max for reconsideration following suggestion by
                     Curt Haltiwanger that terms are needed that do not
                     refer to resolution or theta
               Likewise removed _diffrn_standards_decay_%_lt for further
                     consideration, and added _type_conditions esd to
                     _diffrn_standards_decay_% as a measurable quantity
                     (CH/HDF)
               Modified _example_detail for _space_group_symop_operation_xyz
                     to use a full and unambiguous wording in accordance
                     with International Tables A (CH/IDB/HDF)
   2003-09-29  Removed "_type_conditions esd" from the remaining *_gt and
                     *_lt items at the suggestion of Gotzon Madariaga:
                     since these are ceiling/floor values a measurable
                     uncertainty is pointless (BMcM)
   2003-10-01  Fixed some typos following checking by IDB (BMcM)
   2003-10-03  BMcM: Final editorial pass. Added _related_function alternate
                     to _exptl_crystal_colour. Also added this flag to the
                     new items which replace existing ones:
                     _atom_site_refinement_flags_* and the _space_group_ items
   2003-10-04  Release version 2.3. IUCr