CIF required items for single-crystal reports
This page lists the data items that are required for a single-crystal study. For a list of items to include in a powder diffraction study, please click here.
Detailed descriptions of these data items are given in the core CIF dictionary [see also Hall et al. (1991). Acta Cryst. A47, 655-685].
New names listed below are flagged with (new) and in some cases are followed by old names [in regular type and flagged with (old)] which are accepted but will be discontinued in the future. Authors may also include other data items in the CIF (see the two _publ_manuscript_incl_extra_ entries towards the end of the list) provided their data names are also listed in the _publ_contact_letter text.
Text items | |
_publ_contact_author_name | Contact author's name |
_publ_contact_author_address | Contact author's address |
_publ_contact_author | Contact author's name and address (old) |
_publ_contact_author_email | E-mail address to be published |
_publ_contact_author_fax | For editorial communications |
_publ_contact_author_phone | For editorial communications |
_publ_contact_letter | Letter of submission, with date |
_publ_requested_journal | 'Acta Crystallographica Section C' |
_publ_section_title | Title of paper |
_publ_section_title_footnote | Footnote to title of paper |
_publ_author_name | List of author(s) name(s) |
_publ_author_footnote | Footnote(s) to author(s) name(s) |
_publ_author_address | Author(s) address(es) |
_publ_section_synopsis | Synopsis (approximately two sentences) for inclusion in the Contents listing of the journal; required for all articles |
_publ_section_abstract | Abstract of paper in English |
loop_ _publ_body_element _publ_body_title _publ_body_contents (author defined sections; use of http://publcif.iucr.org recommended) |
Text sections of the article: `element' can be section or subsection; `title' is the title of the section or subsection; `contents' is the text content of the section or subsection |
_publ_section_acknowledgements | Acknowledgements |
_publ_section_references | References |
_publ_section_figure_captions | Legends to figures |
Experimental data (machine and author generated) | |
_publ_section_exptl_prep | Compound preparation details |
_publ_section_exptl_refinement | Special details of the refinement |
_chemical_formula_sum | Chemical formula as sum of elements |
_chemical_formula_moiety | Chemical formula in moieties |
_chemical_formula_weight | Chemical formula mass (Da) |
_chemical_melting_point | Melting point (K) |
_space_group_crystal_system | Code for cell setting |
_space_group_name_H-M_alt _symmetry_space_group_name_H-M (old) |
Space-group symbol, including unique axis |
_space_group_symop_operation_xyz _symmetry_equiv_pos_as_xyz (old) |
Equivalent positions in order used by _geom_ |
_space_group_name_Hall _symmetry_space_group_name_Hall (old) |
The Hall space group symbol |
_space_group_IT_number (optional) _symmetry_Int_Tables_number (old) |
The space group number as used in International Tables, Volume A |
_cell_length_a _cell_length_b _cell_length_c |
Unit-cell lengths (Å) |
_cell_angle_alpha _cell_angle_beta _cell_angle_gamma |
Unit-cell angles (°) |
_cell_volume | Unit-cell volume (Å3) |
_cell_formula_units_Z | Number of formulae per unit cell |
_exptl_crystal_density_diffrn | Density calculated from unit cell and contents (Mg m-3) |
_exptl_crystal_density_meas (optional) | Density measured experimentally (Mg m-3) |
_exptl_crystal_density_method (optional; only use if previous item present) | Method used to measure density experimentally |
_diffrn_radiation_type | Radiation type (e.g. neutron or `Mo Kα') |
_diffrn_radiation_wavelength | Radiation wavelength (Å) |
_cell_measurement_reflns_used | Number of reflections used to measure unit cell |
_cell_measurement_theta_min | Minimum θ of reflections used to measure unit cell (°) |
_cell_measurement_theta_max | Maximum θ of reflections used to measure unit cell (°) |
_cell_measurement_temperature | Measurement temperature (K) |
_exptl_absorpt_coefficient_mu | Linear absorption coefficient (mm-1) |
_exptl_crystal_description | Crystal habit description |
_exptl_crystal_size_max | Maximum dimension of crystal (mm) |
_exptl_crystal_size_mid | Medial dimension of crystal (mm) |
_exptl_crystal_size_min | Minimum dimension of crystal (mm) |
_exptl_crystal_size_rad (alternative to the three preceding items) |
Radius of spherical or cylindrical crystal (mm) |
_exptl_crystal_colour | Crystal colour |
_diffrn_measurement_device_type | Diffractometer make and type |
_diffrn_measurement_device | Diffractometer make and type (old) |
_diffrn_measurement_method | Mode of intensity measurement and scan |
_diffrn_detector_area_resol_mean | Resolution of area detector (pixels mm-1) |
_exptl_absorpt_correction_type | Code for absorption correction |
_exptl_absorpt_process_details | Literature reference for absorption correction [e.g. '(North et al., 1968)'] |
_exptl_absorpt_correction_T_min | Minimum transmission factor from the absorption correction applied (e.g. not including scaling) |
_exptl_absorpt_correction_T_max | Maximum transmission factor from the absorption correction applied (e.g. not including scaling) |
_diffrn_reflns_number | Total number of reflections measured excluding systematic absences |
_reflns_number_total | Number of symmetry-independent reflections excluding systematic absences |
_reflns_number_gt | Number of reflections > σ threshold |
_reflns_threshold_expression | σ expression for F, F2 or I threshold |
_diffrn_reflns_theta_max | Maximum θ of measured reflections (°) |
_diffrn_reflns_theta_min | Minimum θ of measured reflections (°) |
_diffrn_reflns_theta_full | θ to which available reflections are close to 100% complete (°) |
_diffrn_measured_fraction_theta_max | Fraction of unique reflections measured to θmax |
_diffrn_measured_fraction_theta_full | Fraction of unique reflections measured to θfull |
_diffrn_reflns_av_R_equivalents | R factor for symmetry-equivalent intensities |
_diffrn_reflns_limit_h_min _diffrn_reflns_limit_h_max |
Minimum/maximum h index of measured data |
_diffrn_reflns_limit_k_min _diffrn_reflns_limit_k_max |
Minimum/maximum k index of measured data |
_diffrn_reflns_limit_l_min _diffrn_reflns_limit_l_max |
Minimum/maximum l index of measured data |
_diffrn_reflns_Laue_measured_fraction_max (SHELXL2012 or later) | Fraction of Laue unique reflections (symmetry-independent in the Laue group) measured out to θmax |
_diffrn_reflns_Laue_measured_fraction_full (SHELXL2012 or later) | Fraction of Laue unique reflections (symmetry-independent in the Laue group) measured out to θfull |
_diffrn_reflns_point_group_measured_fraction_max (SHELXL2012 or later) | Fraction of crystal point-group unique reflections (i.e. symmetry-independent in the crystal point group) measured out to θmax |
_diffrn_reflns_point_group_measured_fraction_full (SHELXL2012 or later) | Fraction of crystal point-group unique reflections (i.e. symmetry-independent in the crystal point group) measured out to θfull |
_reflns_Friedel_coverage (SHELXL2012 or later) | The proportion of Friedel-related reflections present in the number of reported unique reflections |
_reflns_Friedel_fraction_max (SHELXL2012 or later) | The number of unique Friedel pairs measured divided by the number that would be possible theoretically, ignoring centric projections and systematic absences out to θmax |
_reflns_Friedel_fraction_full (SHELXL2012 or later) | The number of unique Friedel pairs measured divided by the number that would be possible theoretically, ignoring centric projections and systematic absences out to θfull |
_diffrn_standards_number (optional - only needed if a point detector is used) |
Number of standards used in measurement (enter zero if none) |
_diffrn_standards_interval_count (optional - only needed if a point detector is used) _diffrn_standards_interval_time (alternate) |
Number of measurements between standards Time (min) between standards |
_diffrn_standards_decay_% (optional - only needed if a point detector is used) |
Percentage decrease in standards intensity |
_refine_ls_structure_factor_coef | Code for F, F2 or I used in least-squares refinement |
_refine_ls_R_factor_gt | R factor of F for reflections > threshold |
_refine_ls_wR_factor_ref | R factor of coefficient for refinement reflections |
_refine_ls_goodness_of_fit_ref | Goodness of fit S for refinement reflections |
_refine_ls_number_reflns | Number of reflections used in refinement |
_refine_ls_number_parameters | Number of parameters refined |
_refine_ls_number_restraints | Number of restraints applied during refinement |
_refine_ls_weighting_scheme | Code for weight type |
_refine_ls_weighting_details | Weighting expression |
_refine_ls_hydrogen_treatment | Code for H-atom treatment |
_refine_ls_shift/su_max | Maximum shift/s.u. ratio after final refinement cycle |
_refine_ls_shift/esd_max | Maximum shift/e.s.d. ratio after final refinement cycle (old) |
_refine_diff_density_max _refine_diff_density_min |
Maximum/minimum values of final difference map (e Å-3) |
_refine_ls_extinction_method | Description of extinction methods applied |
_refine_ls_extinction_coef | Extinction coefficient applied in corrections |
_refine_ls_abs_structure_details | Absolute structure method and Friedel-pair number |
_refine_ls_abs_structure_Flack | Measure of absolute structure. May be used to report the estimated Flack x parameter, the Hooft y parameter, the Parsons quotient z parameter or the refined Flack parameter (using TWIN/BASF) |
_chemical_absolute_configuration | Code for specifying how the absolute structure was assigned |
_computing_data_collection | Reference to data-collection software |
_comput ing_cell_refinement | Reference to cell-refinement software |
_computing_data_reduction | Reference to data-reduction software |
_computing_structure_solution | Reference to structure-solution software |
_computing_structure_refinement | Reference to structure-refinement software |
_computing_molecular_graphics | Reference to visualization software |
_computing_publication_material | Reference to publication preparation software |
loop_ | |
_atom_site_label | Unique label identifying the atom site |
_atom_site_type_symbol | Atom type symbol (usually element symbol) |
_atom_site_fract_x _atom_site_fract_y _atom_site_fract_z |
Fractional coordinates of atom site |
_atom_site_U_iso_or_equiv | Isotropic atomic displacement parameter, or equivalent from anisotropic atomic displacement parameters |
_atom_site_adp_type | Atomic displacement parameter type |
_atom_site_occupancy | Occupancy fraction for site (default is 1.0). Normally, the occupancy is 1.0, even on a special position. Occupancy is < 1 usually only for disorder. |
_atom_site_site_symmetry_order | This is the number of times application of the crystallographic symmetry operators of the space group to the coordinates given for this site generates the same set of coordinates. |
_atom_site_site_symmetry_multiplicity (alternative to _atom_site_site_symmetry_order) | The number of different sites that are generated by the application of the space-group symmetry to the coordinates given for this site. It is equal to the multiplicity given for this Wyckoff site in International Tables for Crystallography Volume A (2002) |
_atom_site_site_symmetry_multiplicity (old) | Replaced by atom_site_site_site_symmetry_multiplicity given above because of inconsistent usage |
_atom_site_calc_flag | Code to signal whether the site coordinates have been determined from the intensities or calculated from the geometry of surrounding sites |
_atom_site_refinement_flags_posn | Flags for specifying restraints or constraints applied to the positional coordinates of the atom |
_atom_site_refinement_flags_adp | Flags for specifying restraints or constraints applied to the atomic displacement parameters of the atom |
atom_site_refinement_flags_occupancy | Flags for specifying restraints or constraints applied to the occupancy of the atom |
_atom_site_refinement_flags (alternative to the three preceding items) |
A concatenated series of single-letter flags for specifying restraints or constraints applied to the atom |
_atom_site_disorder_assembly | Code that identifies functional group suffering disorder |
_atom_site_disorder_group | Code that identifies disorder group |
loop_ | |
_atom_type_symbol | Atom type symbol (usually element symbol) |
_atom_type_description | Description of atom type |
_atom_type_scat_source | Reference to scattering factors applied |
_atom_type_scat_dispersion_real | Real anomalous-dispersion value applied |
_atom_type_scat_dispersion_imag | Imaginary anomalous-dispersion value applied |
loop_ | |
_atom_site_aniso_label | Unique label identifying the atom site |
_atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_23 |
Elements of anisotropic atomic displacement parameter tensor |
loop_ | |
_geom_bond_atom_site_label_1 _geom_bond_atom_site_label_2 |
Labels identifying the atom sites 1 and 2 |
_geom_bond_site_symmetry_1 _geom_bond_site_symmetry_2 |
Symmetry codes (e.g. 2_554) for atom sites 1 and 2 |
_geom_bond_distance | Distance between atom sites 1 and 2 (Å) |
_geom_bond_publ_flag | Flag for print request (yes or no) |
loop_ | |
_geom_angle_atom_site_label_1 _geom_angle_atom_site_label_2 _geom_angle_atom_site_label_3 |
Labels identifying the atom sites 1, 2 and 3 |
_geom_angle_site_symmetry_1 _geom_angle_site_symmetry_2 _geom_angle_site_symmetry_3 |
Symmetry codes for atom sites 1, 2 and 3 |
_geom_angle | Angle between atom sites 1, 2 and 3 (°) |
_geom_angle_publ_flag | Flag for print request (yes or no) |
loop_ | |
_geom_torsion_atom_site_label_1 _geom_torsion_atom_site_label_2 _geom_torsion_atom_site_label_3 _geom_torsion_atom_site_label_4 |
Labels identifying the atom sites 1, 2, 3 and 4 |
_geom_torsion_site_symmetry_1 _geom_torsion_site_symmetry_2 _geom_torsion_site_symmetry_3 _geom_torsion_site_symmetry_4 |
Symmetry codes for atom sites 1, 2, 3 and 4 |
_geom_torsion | Torsion angle between atom sites 1, 2, 3 and 4 (°) |
_geom_torsion_publ_flag | Flag for print request (yes or no) |
loop_ | |
_geom_hbond_atom_site_label_D | Donor-atom label in hydrogen bond |
_geom_hbond_atom_site_label_H | H-atom label in hydrogen bond |
_geom_hbond_atom_site_label_A | Acceptor-atom label in hydrogen bond |
_geom_hbond_site_symmetry_D | Symmetry code for donor site |
_geom_hbond_site_symmetry_H | Symmetry code for H-atom site |
_geom_hbond_site_symmetry_A | Symmetry code for acceptor site |
_geom_hbond_distance_DH | Donor atom-to-H-atom distance (Å) |
_geom_hbond_distance_HA | H-atom-to-acceptor atom distance (Å) |
_geom_hbond_distance_DA | Donor atom-to-acceptor atom distance (Å) |
_geom_hbond_angle_DHA | Donor to H to acceptor angle (°) |
_geom_hbond_publ_flag | Flag for print request (yes or no) |
Author requested items | |
loop_ | |
_publ_manuscript_incl_extra_item | Additional CIF item submitted for publication |
_publ_manuscript_incl_extra_defn | Is item defined in Core dictionary? (yes or no) |
Refinement instructions and input reflection data can now be embedded in the CIF using the following data names | |
_iucr_refine_instructions_details or _shelx_res_file _shelx_res_checksum |
The instructions used to control the refinement program, e.g. the contents of the SHELXL .res file |
_iucr_refine_reflections_details or _shelx_hkl_file _shelx_hkl_checksum |
The (unmerged) reflections used as input to the refinement program, e.g. the contents of the SHELXL .hkl file. This could also contain the reflections from more than one twin domain. |
_shelx_fab_file _shelx_fab_checksum |
When Platon SQUEEZE is used, a *.fab file is created containing partial structure factors representing the SQUEEZEd region. If this is used together with the ABIN instruction of SHELXL2012, the CIF will automatically contain these two items. |
Structure-factor lists should be submitted as separate files with the items below | |
loop_ | |
_refln_index_h _refln_index_k _refln_index_l |
Miller indices h, k and l |
_refln_F_meas _refln_F_squared_meas (alternate) |
Measured F Measured F2 |
_refln_F_sigma _refln_F_squared_sigma (alternate) |
Standard uncertainty of F Standard uncertainty of F2 |
_refln_F_calc _refln_F_squared_calc (alternate) |
Calculated F Calculated F2 |