Index

v0.1
- datasets
  - Point groups (property) - https://schemas.httk.org/defs/v0.1/datasets/pointgroups
    
    Ordered table of crystallographic point-group records. Each item contains point-group classification, finite point-group operations, conjugacy classes, and real and complex character tables generated from cctbx and spgrep.
  - Space groups (property) - https://schemas.httk.org/defs/v0.1/datasets/spacegroups
    
    Ordered table of crystallographic space-group setting records. Each item describes one concrete Hall/International Tables setting of a space group, including symbols, classifications, symmetry operations, asymmetric-unit information, Wyckoff positions, and related auxiliary data. The companion top-level indicies.index_hall_entry_to_spacegroups lookup maps normalized Hall entries to indices in this list; it is not an OPTIMADE property.
  - Transformations (property) - https://schemas.httk.org/defs/v0.1/datasets/transformations
    
    Ordered table of crystallographic transformation records. Each item describes transformations and normalizer information for one concrete International Tables H-M entry. In transformations_hm_entry.json.gz, items are keyed for lookup by the companion top-level indicies.index_hm_entry_to_transformations_per_hm_entry object; that index is not an OPTIMADE property.
- entrytypes
  - httk point group symmetry fields (entrytype) - https://schemas.httk.org/defs/v0.1/entrytypes/pointgroups
  - httk space group symmetry fields (entrytype) - https://schemas.httk.org/defs/v0.1/entrytypes/spacegroups
  - httk transformation fields (entrytype) - https://schemas.httk.org/defs/v0.1/entrytypes/transformations
- properties
  - core
    - Fraction (property) - https://schemas.httk.org/defs/v0.1/properties/core/fraction
      
      A numerical representation formed as the quotient of two numbers represented as a string.
    - Fractional coordinate precision (property) - https://schemas.httk.org/defs/v0.1/properties/core/fractional_coordinate_precision
      
      The absolute precision of a set of fractional coordinates, in fractional units.
    - Length precision (property) - https://schemas.httk.org/defs/v0.1/properties/core/length_precision
      
      The absolute precision of a stated length, in ångström.
    - String markups (property) - https://schemas.httk.org/defs/v0.1/properties/core/string_markups
      
      Strings with alternate markup and/or encoding for display rendering.
  - pointgroups
    - Complex character table (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/character_table_complex
      
      Complex irreducible character table of the crystallographic point group.
    - Real character table (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/character_table_real
      
      Real irreducible character table of the crystallographic point group.
    - Conjugacy classes (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/conjugacy_classes
      
      Conjugacy classes of a crystallographic point group.
    - Crystal system (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/crystal_system
      
      The crystal system of the space group or point group.
    - Hermann-Mauguin symbol (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/hm_symbol
      
      Hermann-Mauguin point-group symbol used as the key and display symbol for a point-group record.
    - is centrosymmetric (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/is_centrosymmetric
      
      Boolean flag indicating whether the point group contains inversion symmetry.
    - Laue class (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/laue_class
      
      The Laue class associated with the space group or point group.
    - Number of conjugacy classes (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/n_conjugacy_classes
      
      Number of conjugacy classes in the crystallographic point group.
    - Number of pointgroup symops (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/n_pointgroup_symops
      
      Number of point-group symmetry operations.
    - Order of the point group (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/order
      
      Order of the point group, i.e. the number of operations in the finite point group.
    - Schoenflies symbol (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/schoenflies
      
      The Schoenflies symbol for the crystallographic point group.
    - Schoenflies symbol markups (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/schoenflies_markup
      
      Display-oriented renderings of the Schoenflies symbol in schoenflies. The plain string value is stored in the corresponding unsuffixed property; this object only provides alternate markup forms for display.
    - Symmetry operations (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/symops
      
      Full list of symmetry-operation descriptors for a point group. Each list member is an op object as defined by /defs/v0.1/properties/symmetry/op. Point-group operations have a zero translation part, so the screw_glide and origin_shift classification fields are omitted.
  - spacegroups
    - Asymmetric unit (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/asu
      
      Direct-space asymmetric unit for the space-group setting, represented as a bounded non-recursive set of half-space cuts and boundary ownership rules.
    - Asymmetric-unit cut (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/asu_cut
      
      One serialized asymmetric-unit half-space cut or logical cut expression in the recursive cctbx source representation.
    - Asymmetric unit markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/asu_markup
      
      Display-oriented renderings of the plain-string asymmetric-unit restrictions in asu_str.
    - Shape-only asymmetric unit markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/asu_shape_only_markup
      
      Display-oriented renderings of the plain-string shape-only asymmetric-unit restrictions in asu_shape_only_str.
    - Shape-only asymmetric unit string (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/asu_shape_only_str
      
      Plain string rendering of the geometric shape part of the asymmetric-unit restrictions, without conditional refinements.
    - Asymmetric unit string (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/asu_str
      
      Plain string rendering of the asymmetric-unit restrictions for the space-group setting.
    - Bravais type (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/bravais_type
      
      The Bravais type of the translational lattice.
    - Cctbx FFT grid factors (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/cctbx_fft_grid_factors
      
      FFT grid-factor requirements derived from cctbx for the space group, its structure seminvariants, and its Euclidean normalizer.
    - Centering translations (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/centering_translations
      
      Centering translations of the conventional cell.
    - Centring type (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/centring_type
      
      The lattice centring symbol for the crystallographic setting.
    - Crystal system (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/crystal_system
      
      The crystal system of the space group or point group.
    - Hall symbol (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hall
      
      The Hall symbol for a crystallographic space-group setting.
    - Hall symbol aliases (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hall_aliases
      
      Alternate ASCII Hall symbols or Hall-setting keys associated with the same generated setting.
    - Hall alias markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hall_aliases_markup
      
      Display-oriented renderings corresponding element-by-element to the alternate Hall symbols in hall_aliases.
    - Hall entry (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hall_entry
      
      Normalized Hall-table entry key used internally by the generated datasets.
    - Hall symbol markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hall_markup
      
      Display-oriented renderings of the Hall symbol in hall.
    - Harker planes (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/harker_planes
      
      Harker planes of the space group in fractional Patterson coordinates.
    - Universal cctbx Hermann-Mauguin symbol (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_cctbx_universal
      
      Universal Hermann-Mauguin symbol returned by cctbx for this setting.
    - Hermann-Mauguin entry (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_entry
      
      The Hermann-Mauguin entry label for a conventional space-group setting from table A1.4.2.7 of the International Tables for Crystallography (2006). Volume B, Reciprocal space. ISBN: 978-0-7923-6592-1, doi:10.1107/97809553602060000102.
    - Hermann-Mauguin entry aliases (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_entry_aliases
      
      Alternative Hermann-Mauguin entry labels from International Tables for Crystallography Volume B table A1.4.2.7 that identify the same generated Hall-symbol row as hm_entry.
    - Hermann-Mauguin entry markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_entry_markup
      
      Display-oriented renderings of the Hermann-Mauguin entry label in hm_entry.
    - Extended Hermann-Mauguin symbol (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_extended
      
      The setting-specific extended Hermann-Mauguin symbol for the space-group setting.
    - Extended Hermann-Mauguin symbol aliases (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_extended_aliases
      
      Alternate ASCII forms of hm_extended that are accepted for the same generated setting.
    - Extended Hermann-Mauguin alias markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_extended_aliases_markup
      
      Display-oriented renderings corresponding element-by-element to the alternate extended Hermann-Mauguin symbols in hm_extended_aliases.
    - Extended Hermann-Mauguin symbol markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_extended_markup
      
      Display-oriented renderings of the extended Hermann-Mauguin symbol in hm_extended.
    - Extended Hermann-Mauguin symbol in old notation (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_extended_old
      
      The older extended Hermann-Mauguin symbol retained as an alias for symbols superseded by newer e-glide notation.
    - Full Hermann-Mauguin symbol (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_full
      
      The setting-specific full Hermann-Mauguin symbol for the space-group setting.
    - Full Hermann-Mauguin symbol aliases (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_full_aliases
      
      Alternate ASCII forms of hm_full that are accepted for the same generated setting.
    - Full Hermann-Mauguin alias markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_full_aliases_markup
      
      Display-oriented renderings corresponding element-by-element to the alternate full Hermann-Mauguin symbols in hm_full_aliases.
    - Full Hermann-Mauguin symbol markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_full_markup
      
      Display-oriented renderings of the setting-specific full Hermann-Mauguin symbol in hm_full.
    - Full Hermann-Mauguin symbol in old notation (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_full_old
      
      The older full Hermann-Mauguin symbol retained as an alias for symbols superseded by newer e-glide notation.
    - Standard full Hermann-Mauguin symbol (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_full_std
      
      The International Tables standard full Hermann-Mauguin symbol for the space-group type.
    - Standard full Hermann-Mauguin symbol markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_full_std_markup
      
      Display-oriented renderings of the ITA-standard full Hermann-Mauguin symbol in hm_full_std.
    - Short Hermann-Mauguin symbol (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_short
      
      The setting-specific short Hermann-Mauguin symbol for the space-group setting.
    - Short Hermann-Mauguin symbol aliases (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_short_aliases
      
      Alternate ASCII forms of hm_short that are accepted for the same generated setting.
    - Short Hermann-Mauguin alias markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_short_aliases_markup
      
      Display-oriented renderings corresponding element-by-element to the alternate short Hermann-Mauguin symbols in hm_short_aliases.
    - Short Hermann-Mauguin symbol markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_short_markup
      
      Display-oriented renderings of the setting-specific short Hermann-Mauguin symbol in hm_short.
    - Short Hermann-Mauguin symbol in old notation (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_short_old
      
      The older short Hermann-Mauguin symbol retained as an alias for symbols superseded by newer e-glide notation.
    - Standard short Hermann-Mauguin symbol (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_short_std
      
      The International Tables standard short Hermann-Mauguin symbol for the space-group type.
    - Standard short Hermann-Mauguin symbol markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/hm_short_std_markup
      
      Display-oriented renderings of the ITA-standard short Hermann-Mauguin symbol in hm_short_std.
    - is centric (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/is_centric
      
      Boolean flag indicating whether the space group is centric.
    - is chiral (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/is_chiral
      
      Boolean flag indicating whether the space group is chiral.
    - is enantiomorphic (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/is_enantiomorphic
      
      Boolean flag indicating whether the space-group type belongs to an enantiomorphic pair.
    - is reference setting (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/is_reference_setting
      
      Boolean flag indicating whether this Hall setting is the selected reference setting for its International Tables space-group number.
    - International Tables coordinate-system code (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/it_coordinate_system_code
      
      The International Tables coordinate-system code for the setting.
    - International Tables space-group number (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/it_number
      
      The International Tables space-group number.
    - International Tables number of the enantiomorph (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/it_number_enantiomorphic
      
      International Tables number of the enantiomorphic partner space group, when one exists.
    - Laue class (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/laue_class
      
      The Laue class associated with the space group or point group.
    - Number of centering translations (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/n_centering_translations
      
      Number of centering translations in the conventional cell of the space-group setting.
    - Number of pointgroup symops (property) - https://schemas.httk.org/defs/v0.1/properties/pointgroups/n_pointgroup_symops
      
      Number of point-group symmetry operations.
    - Number of symops (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/n_symops
      
      Number of symmetry operations in the finite operation list of the generated entry.
    - Point-group Hermann-Mauguin symbol (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/point_group
      
      The Hermann-Mauguin point-group symbol for the crystallographic point group of the space group.
    - Schoenflies symbol (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/schoenflies
      
      The Schoenflies symbol for the space-group type.
    - Schoenflies symbol markups (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/schoenflies_markup
      
      Display-oriented renderings of the space-group Schoenflies symbol in schoenflies. The plain string value is stored in the corresponding unsuffixed property; this object only provides alternate markup forms for display.
    - Setting annotation (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/setting
      
      Setting suffix or setting annotation extracted from the cctbx universal Hermann-Mauguin symbol in hm_cctbx_universal.
    - International Tables setting code n:c (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/setting_it_nc
      
      International Tables setting identifier in n:c notation.
    - International Tables setting-code aliases (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/setting_it_nc_aliases
      
      A list of International Tables n:c setting identifiers that are alternatives to the one designated as the main one.
    - Setting plaintext (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/setting_plaintext
      
      Human-readable description of the International Tables coordinate-system setting.
    - Space-group symbols (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/spacegroup_symbols
      
      Ordered table of conventional space-group symbol rows.
    - Spglib Hall symbol (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/spglib_hall
      
      The Hall symbol for this setting as spelled by the spglib library.
    - Spglib Hall numbers (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/spglib_hall_numbers
      
      The spglib Hall numbers corresponding to this Hall setting.
    - Structure seminvariants (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/structure_seminvariants
      
      Structure seminvariant vectors and moduli for the space-group setting.
    - Symmetry operations (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/symops
      
      Full list of symmetry-operation descriptors for a space-group setting.
    - Symmetry operation generators (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/symops_generators
      
      Minimal generator subset of the full symmetry-operation group for a space-group setting.
    - Symmetry operations modulo centering translations (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/symops_mod_centering
      
      Representative symmetry-operation descriptors modulo centering translations.
    - Representative symmetry operations (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/symops_representative
      
      Representative symmetry-operation descriptors modulo centering translations.
    - Wyckoff positions (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/wyckoff
      
      Wyckoff-position table for a specific space-group setting.
    - Wyckoff sets (property) - https://schemas.httk.org/defs/v0.1/properties/spacegroups/wyckoff_sets
      
      Sets of Wyckoff letters related by normalizer operations.
  - symmetry
    - Affine transformation (property) - https://schemas.httk.org/defs/v0.1/properties/symmetry/affine_transformation
      
      An affine transformation acting on fractional crystallographic coordinates.
    - Basis transformation (property) - https://schemas.httk.org/defs/v0.1/properties/symmetry/basis_transform
      
      One crystallographic transform between coordinate descriptions, settings, cells, or related group embeddings.
    - Centering translation (property) - https://schemas.httk.org/defs/v0.1/properties/symmetry/centering_translation
      
      One centering translation of a conventional crystallographic cell.
    - Operation (property) - https://schemas.httk.org/defs/v0.1/properties/symmetry/op
      
      Information related to a crystallographic operation acting within one coordinate setting.
    - Operation xyz (property) - https://schemas.httk.org/defs/v0.1/properties/symmetry/op_xyz
      
      Coordinate operation expressed in the algebraic xyz form, also known as Jones' faithful representation (Bradley & Cracknell, 1972: pp. 35-37; adapted for computer strings).
    - Wyckoff position (property) - https://schemas.httk.org/defs/v0.1/properties/symmetry/wyckoff_position
      
      Information related to a Wyckoff position in a space-group setting.
  - transformations
    - Affine images (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/affine_images
      
      Same-space-group affine images for a standard setting.
    - Affine normalizer (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/affine_normalizer
      
      Affine normalizer coset representatives for one crystallographic space-group setting.
    - Affine normalizer coset data (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/affine_normalizer_coset_data
      
      Ordered table of bounded affine normalizer coset-representative data for crystallographic space groups, with one item for each Hall setting.
    - Affine normalizer cosets (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/affine_normalizer_cosets
      
      Runtime list of bounded affine normalizer coset representatives modulo the space group.
    - Backward lift criteria (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/backward_lift_criteria
      
      Criteria table for one supergroup IT number used to lift occupied Wyckoff data from a subgroup back to that supergroup along a chosen Bärnighausen transform.
    - Bärnighausen subgroup transforms (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/baernighausen
      
      Bärnighausen subgroup transform table for one parent setting or space-group type.
    - Continuous normalizer (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/continuous_normalizer
      
      Parameterized continuous normalizer subspace for a setting.
    - Euclidean normalizer (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/euclidean_normalizer
      
      Finite Euclidean normalizer operations for one crystallographic space-group setting.
    - Hall to IT standard transform (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/hall_to_it_std_transform
      
      Exact basis and origin transform from one stored Hall setting to the International Tables standard Hall setting of the same space-group type.
    - Subgroup or transform index (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/index
      
      Subgroup or transform index.
    - Isomorphic subgroup transforms (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/isomorphic_subgroups
      
      Isomorphic subgroup transforms of bounded index for one parent setting or space-group type.
    - Klassengleiche subgroup subtype (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/k_subtype
      
      Subtype of a klassengleiche (k) subgroup relation.
    - Maximal subgroup relations (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/maximal_subgroup_relations
      
      Maximal non-isomorphic subgroup relations for International Tables space-group types.
    - Number of coset representatives (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/n_coset_representatives
      
      Number of nontrivial coset representatives retained after deduplication modulo the space group.
    - Number of cosets (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/n_cosets
      
      Number of affine normalizer coset representatives stored for the setting.
    - Number of linear parts (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/n_linear_parts
      
      Number of distinct linear matrix parts represented in a normalizer or transform table.
    - Number of orthogonal cosets (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/n_orthogonal_cosets
      
      Number of orthogonal affine normalizer coset representatives stored for the setting.
    - Number of raw candidates (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/n_raw_candidates
      
      Number of candidate affine operations considered before filtering and deduplication.
    - Number of unique candidates (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/n_unique_candidates
      
      Number of candidate affine operations remaining after exact duplicate removal.
    - Orthogonal affine normalizer (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/orthogonal_affine_normalizer
      
      Orthogonal affine normalizer coset representatives for one crystallographic space-group setting.
    - Orthogonal affine normalizer cosets (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/orthogonal_affine_normalizer_cosets
      
      Runtime list of orthogonal signed-permutation affine normalizer coset representatives modulo the space group.
    - Same space group affine images std (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/same_space_group_affine_images_std
      
      Same-space-group affine-image record for one International Tables standard setting.
    - Maximal subgroup type (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/subgroup_type
      
      International Tables maximal subgroup class.
    - Criterion target (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/target
      
      Exact target vector or scalar of a generated linear criterion.
    - To Hall entry (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/to_hall_entry
      
      Target Hall-entry key to which a setting transform maps the current Hall setting.
    - Transformations per H-M entry (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/transformations_per_hm_entry
      
      Transformation data grouped by H-M entry.
    - Transformations per IT number (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/transformations_per_it_number
      
      Standard-setting transformation data grouped by International Tables space-group number.
    - Wyckoff splitting (property) - https://schemas.httk.org/defs/v0.1/properties/transformations/wyckoff_splitting
      
      Wyckoff-position splitting data associated with a subgroup or same-space-group transform.
- standards
  - httk definition provider standard (standard) - https://schemas.httk.org/defs/v0.1/standards/httk
    
    The httk definition provider standard, comprising the spacegroups, pointgroups, and transformations entry types for crystallographic symmetry data.