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OPTIMADE provider "Theoretical Crystallography Open Database" (id: tcod)

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General information

Short description: Open-access collection of theoretically calculated or refined crystal structures of organic, inorganic, metal-organic compounds and minerals, excluding biopolymers

Project homepage: https://www.crystallography.net/tcod

Index Meta-Database URL: https://providers.optimade.org/index-metadbs/tcod

Number of structures: 7,488

Detailed information

(information checked on Thursday October 30, 2025 at 05:34 UTC)
Index metaDB (/info)State of the /info endpoint of the index meta-database found found Index metaDB versionVersion of the index meta-database v1 Index metaDB (/links)State of the /links endpoint of the index meta-database found found

Databases served by this provider

  • Theoretical Crystallography Open Database (tcod, default sub-database)

    https://www.crystallography.net/tcod/optimade

    Open-access collection of theoretically calculated or refined crystal structures of organic, inorganic, metal-organic compounds and minerals, excluding biopolymers

    Properties served by this database:

    By entry type (click to expand):
    • references
      • The full list of standard OPTIMADE properties.
    • structures
      • The full list of standard OPTIMADE properties.
      • _tcod_a Description: The lattice parameter a of the crystal structure.
        Type: float
      • _tcod_acce_code Description: Acta Crystallographica Coeditor Code. Uniquely identifies a publication by IUCr journals and can be used to construct URL of the paper "landing page".
        Type: string
      • _tcod_alpha Description: The lattice parameter alpha of the crystal structure.
        Type: float
      • _tcod_authors Description: The authors that published the paper describing the crystal structure deposited in the COD database, or the authors of the personal communication to COD. NB.: The name syntax uses the BibTeX convention, which is slightly different from the IUCr convention described under the CIF:DescriptionUrl.
        Type: string
      • _tcod_b Description: The lattice parameter b of the crystal structure.
        Type: float
      • _tcod_beta Description: The lattice parameter beta of the crystal structure.
        Type: float
      • _tcod_c Description: The lattice parameter c of the crystal structure.
        Type: float
      • _tcod_calcformula Description: The summary (brutto) formula calculated from the crystal data by the 'cod-tools' package. Ideally, should be the same value as in 'formula'.
        Type: string
      • _tcod_cellformula Description: The summary (brutto) formula of the whole unit cell calculated from the crystal data by the 'cod-tools' package. The number of atoms for each element in the 'cellformula' is 'Z' times higher than the number of atoms for the same element in the 'calcformula'.
        Type: string
      • _tcod_cellpressure Description: The pressure in kilopascals at which the unit cell parameters were measured.
        Type: float
      • _tcod_celltemp Description: The temperature in Kelvins at which the unit cell parameters were measured (not the temperature of synthesis).
        Type: float
      • _tcod_chemname Description: IUPAC or Chemical Abstracts full name of the compound.
        Type: string
      • _tcod_commonname Description: Trivial name by which the compound in the crystal is commonly known.
        Type: string
      • _tcod_compoundsource Description: The description of the source of the compound (or a parent molecule). Includes the place of discovery (for minerals) or the actual source (for natural products).
        Type: string
      • _tcod_date Description: The date the current row of the table was inserted to the COD database.
        Type: string
      • _tcod_diffrpressure Description: The mean hydrostatic pressure in kilopascals at which the intensities were measured.
        Type: float
      • _tcod_diffrtemp Description: The mean temperature in Kelvins at which the diffraction intensities were measured.
        Type: float
      • _tcod_doi Description: The DOI that links to the online paper where the crystal was published.
        Type: string
      • _tcod_duplicateof Description: Specifies that the COD entry containing this data item is considered to be a duplicate of another entry. The COD number of this other entry, which is considered to be "primary" entry for the structure, is specified as a value of this column.
        Type: integer
      • _tcod_firstpage Description: The first page of the scientific paper where the crystal structure was published.
        Type: string
      • _tcod_flags Description: A set (as in SQL or Pascal) that describes various conditions of a COD record: "has coordinates": the entry has atomic coordinates specified; "has disorder": some atoms were modeled as disordered in the unit cell of this entry; "has Fobs": there is a corresponding X-ray reflection file (Fobs or Iobs data) in the COD for this entry, containing the original reflection intensities used to determine this structure.
        Type: string
      • _tcod_gamma Description: The lattice parameter gamma of the crystal structure.
        Type: float
      • _tcod_gofall Description: The least-squares goodness-of-fit parameter S for all reflections after the final cycle of refinement.
        Type: float
      • _tcod_gofgt Description: NOTE: the field stores the same information as the "gofobs" field, however, it should not be removed in order to retain compatibility with existing software. The least-squares goodness-of-fit parameter S for significantly intense reflections (see _reflns_threshold_expression) after the final cycle of refinement.
        Type: float
      • _tcod_gofobs Description: NOTE: the field stores the same information as the "gofgt" field, however, it should not be removed in order to retain compatibility with existing software. The least-squares goodness-of-fit parameter S for significantly intense reflections (see _reflns_threshold_expression) after the final cycle of refinement.
        Type: float
      • _tcod_gofref Description: The least-squares goodness-of-fit parameter S for all reflections included in the refinement after the final cycle of refinement.
        Type: float
      • _tcod_issue Description: The issue of the journal where the scientific paper describing the crystal structure was published.
        Type: string
      • _tcod_journal Description: The name of the journal in which the scientific paper describing the crystal structure was published.
        Type: string
      • _tcod_lastpage Description: The last page of the scientific paper where the crystal structure was published.
        Type: string
      • _tcod_method Description: The method that was used to determine the crystal structure.
        Type: string
      • _tcod_mineral Description: Mineral name accepted by the International Mineralogical Association.
        Type: string
      • _tcod_onhold Description: Specifies the date when the atomic coordinates of the entry, which might be currently on hold (not public), will become available publicly.
        Type: string
      • _tcod_optimal Description: Contains a COD database code for the COD entry that contains optimally solved structure for the crystal or compound under consideration. This optimal structure should be used for all inferences; the current suboptimal structure is provided for illustration purposes only.
        Type: integer
      • _tcod_pressurehist Description: The pressure history of the crystal (human-readable informal description).
        Type: string
      • _tcod_radiation Description: The type of radiation that was used to determine the crystal structure.
        Type: string
      • _tcod_radSymbol Description: The IUPAC symbol for the X-ray wavelength for the probe radiation.
        Type: string
      • _tcod_radType Description: The type of the radiation used to determine the structure of the crystal. This is used to give a more detailed description than _diffrn_radiation_probe and is typically a description of the X-ray wavelength in Siegbahn notation.
        Type: string
      • _tcod_Rall Description: Residual factor for all reflections satisfying the resolution limits established by _refine_ls_d_res_high and _refine_ls_d_res_low.
        Type: float
      • _tcod_RFsqd Description: Residual factor R(Fsqd), calculated on the squared amplitudes of the observed and calculated structure factors, for significantly intense reflections (satisfying _reflns_threshold_expression) and included in the refinement.
        Type: float
      • _tcod_RI Description: Residual factor R(I) for significantly intense reflections (satisfying _reflns_threshold_expression) and included in the refinement. This is most often calculated in Rietveld refinements against powder data, where it is referred to as R~B~ or R~Bragg~.
        Type: float
      • _tcod_Robs Description: Residual factor for the reflections (with number given by _reflns_number_gt) judged significantly intense (i.e. satisfying the threshold specified by _reflns_threshold_expression) and included in the refinement. The reflections also satisfy the resolution limits established by _refine_ls_d_res_high and _refine_ls_d_res_low. This is the conventional R factor.
        Type: float
      • _tcod_Rref Description: This data value is not described in official IUCr dictionaries, but many CIF files use it. Should be roughly equivalent to Robs.
        Type: float
      • _tcod_sg Description: Space group symbol, Hermann-Mauguin or superspace group symbol
        Type: string
      • _tcod_sgHall Description: Space group symbol as described by Hall.
        Type: string
      • _tcod_siga Description: The standard uncertainty of the lattice parameter a of the crystal structure.
        Type: float
      • _tcod_sigalpha Description: The standard uncertainty of the lattice parameter alpha of the crystal structure.
        Type: float
      • _tcod_sigb Description: The standard uncertainty of the lattice parameter b of the crystal structure.
        Type: float
      • _tcod_sigbeta Description: The standard uncertainty of the lattice parameter beta of the crystal structure.
        Type: float
      • _tcod_sigc Description: The standard uncertainty of the lattice parameter c of the crystal structure.
        Type: float
      • _tcod_sigcellpressure Description: The standard uncertainty of the 'cellpressure' value.
        Type: float
      • _tcod_sigcelltemp Description: The standard uncertainty of the temperature at which the crystal structure was determined.
        Type: float
      • _tcod_sigdiffrpressure Description: The standard uncertainty of the 'diffrpressure' value
        Type: float
      • _tcod_sigdiffrtemp Description: The standard uncertainty of the 'diffrtemp' value
        Type: float
      • _tcod_siggamma Description: The standard uncertainty of the lattice parameter gamma of the crystal structure.
        Type: float
      • _tcod_sigvol Description: The standard uncertainty of the volume of the crystal structure.
        Type: float
      • _tcod_smiles Description: The SMILES (Simplified Molecular Input Line Entry Specification) descriptor for the structure.
        Type: string
      • _tcod_status Description: Describes the severity of errors if such are detected in COD entries. Permitted values are: NULL, 'warnings', 'errors', 'retracted'.
        Type: string
      • _tcod_svnrevision Description: The Subversion revision of the file that was used to produce the SQL table row.
        Type: integer
      • _tcod_text Description: A concatenation of all descriptive fields in the table: my $text = join( '\n', map { Unicode2:cif2unicode($_) } ( $authors, $title, $journal, $volume . ( $issue? ( $volume ? "($issue)" : "(issue $issue)") : "" ), "(" . $year . ")", ( $last_page ? $first_page . "-" . $last_page : $first_page )) ); Retained here for compatibility with the first version of the COD.
        Type: string
      • _tcod_thermalhist Description: The thermal history of the crystal (human-readable informal description).
        Type: string
      • _tcod_time Description: The time the current row of the table was inserted to the COD database.
        Type: string
      • _tcod_title Description: The title of the scientific paper where the crystal structure was published.
        Type: string
      • _tcod_vol Description: The volume of the crystal structure (calculated by 'cod-tools' from the cell constants).
        Type: float
      • _tcod_volume Description: The volume of the journal where the scientific paper describing the crystal structure was published.
        Type: integer
      • _tcod_wavelength Description: The wavelength in Ångstrøms that was used to determine the crystal structure.
        Type: float
      • _tcod_wRall Description: Weighted residual factors for all reflections.
        Type: float
      • _tcod_wRobs Description: Weighted residual factors for significantly intense reflections (satisfying _reflns_threshold_expression) included in the refinement.
        Type: float
      • _tcod_wRref Description: Weighted residual factors for all reflections included in the refinement.
        Type: float
      • _tcod_year Description: The year of publication of this crystal structure.
        Type: integer
      • _tcod_Z Description: The number of the formula units in the unit cell.
        Type: integer
      • _tcod_Zprime Description: The number of the formula units in the unit cell ('Z') divided by the number of independent general positions.
        Type: float

    Validation

    ValidationResults of validation Passed 47 / 49
    ❌ https://www.crystallography.net/tcod/optimade/v1/info/structures

    ValidationError: 26 validation errors for EntryInfoResponse
    data.properties._tcod_RFsqd.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_RFsqd', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_RI.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_RI', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_Rall.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_Rall', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_Robs.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_Robs', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_Rref.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_Rref', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_Z.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_Z', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_Zprime.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_Zprime', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_radSymbol.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_radSymbol', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_radType.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_radType', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_sgHall.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_sgHall', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_wRall.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_wRall', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_wRobs.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_wRobs', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.properties._tcod_wRref.[key]
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_wRref', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.0
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_RFsqd', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.1
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_RI', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.2
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_Rall', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.3
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_Robs', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.4
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_Rref', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.5
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_Z', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.6
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_Zprime', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.41
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_radSymbol', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.42
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_radType', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.45
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_sgHall', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.66
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_wRall', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.67
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_wRobs', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch
    data.output_fields_by_format.json.68
    String should match pattern '^[a-z_][a-z_0-9]+$' [type=string_pattern_mismatch, input_value='_tcod_wRref', input_type=str]
    For further information visit https://errors.pydantic.dev/2.12/v/string_pattern_mismatch


    ❌ https://www.crystallography.net/tcod/optimade/v1

    ResponseError: Unable to generate filters for endpoint structures: 'info/structures' response was malformed.