XmlmmCIF equivalent: exptl_crystal Data items in the EXPTL_CRYSTAL category record details about experimental measurements on the crystal or crystals used, such as shape, size, density, and so on. XmlmmCIF equivalent: exptl_crystal/F_000 The effective number of electrons in the crystal unit cell contributing to F(000). It may contain dispersion contributions, and is calculated as F(000) = [ sum (f~r~^2^ + f~i~^2^) ]^1/2^ f~r~ = real part of the scattering factors at theta = 0 f~i~ = imaginary part of the scattering factors at theta = 0 XmlmmCIF equivalent: exptl_crystal/colour The colour of the crystal. XmlmmCIF equivalent: exptl_crystal/density_Matthews The density of the crystal, expressed as the ratio of the volume of the asymmetric unit to the molecular mass of a monomer of the structure, in units of angstroms^3^ per dalton. Ref: Matthews, B. W. (1960). J. Mol. Biol., 33, 491-497 XmlmmCIF equivalent: exptl_crystal/density_diffrn Density values calculated from crystal cell and contents. The units are megagrams per cubic metre (grams per cubic centimetre). XmlmmCIF equivalent: exptl_crystal/density_meas Density values measured using standard chemical and physical methods. The units are megagrams per cubic metre (grams per cubic centimetre). XmlmmCIF equivalent: exptl_crystal/density_meas_temp The temperature in kelvins at which _exptl_crystal.density_meas was determined. XmlmmCIF equivalent: exptl_crystal/density_method The method used to measure _exptl_crystal.density_meas. XmlmmCIF equivalent: exptl_crystal/density_percent_sol Density value P calculated from crystal cell and contents,expressed as percent solvent. P = 1 - (1.23 N MMass) / V N = the number of molecules in the unit cell MMass = the molecular mass of each molecule (gm/mole) V = the volume of the unit cell (A^3^) 1.23 = the evaluated conversion factor: (0.74 cm^3^/gm^3^) (10^24^ A^3^/cm^3^) -------------------------------------------------------- (6.02*10^23^) moles/molecule where 0.74 is an assumed value for the partial specific volume of the molecule XmlmmCIF equivalent: exptl_crystal/description A description of the quality and habit of the crystal. Dimensional data are better placed in the data items in the EXPTL_CRYSTAL_FACE category. XmlmmCIF equivalent: exptl_crystal/pdbx_crystal_image_format The image format for the file containing the image of crystal specified as an RFC2045/RFC2046 mime type. XmlmmCIF equivalent: exptl_crystal/pdbx_crystal_image_url The URL for an a file containing the image of crystal. XmlmmCIF equivalent: exptl_crystal/preparation Details of crystal growth and preparation of the crystal (e.g. mounting) prior to the intensity measurements. XmlmmCIF equivalent: exptl_crystal/size_max The maximum dimension of the crystal. This item may appear in a list with _exptl_crystal.id if multiple crystals are used in the experiment. XmlmmCIF equivalent: exptl_crystal/size_mid The medial dimension of the crystal. This item may appear in a list with _exptl_crystal.id if multiple crystals are used in the experiment. XmlmmCIF equivalent: exptl_crystal/size_min The minimum dimension of the crystal. This item may appear in a list with _exptl_crystal.id if multiple crystals are used in the experiment. XmlmmCIF equivalent: exptl_crystal/size_rad The radius of the crystal, if the crystal is a sphere or a cylinder. This item may appear in a list with _exptl_crystal.id if multiple crystals are used in the experiment. XmlmmCIF equivalent: exptl_crystal/id The value of _exptl_crystal.id must uniquely identify a record in the EXPTL_CRYSTAL list. Note that this item need not be a number; it can be any unique identifier.