base class, extends NXobject


One group like this per component can be recorded For a sample consisting of multiple components.


symbolic array lengths to be coordinated between various fields

n_Temp: number of temperatures

n_eField: number of values in applied electric field

n_mField: number of values in applied magnetic field

n_pField: number of values in applied pressure field

n_sField: number of values in applied stress field

Groups cited:



@default: (optional) NX_CHAR

Declares which child group contains a path leading to a NXdata group.

It is recommended (as of NIAC2014) to use this attribute to help define the path to the default dataset to be plotted. See https://www.nexusformat.org/2014_How_to_find_default_data.html for a summary of the discussion.

name: (optional) NX_CHAR

Descriptive name of sample component

chemical_formula: (optional) NX_CHAR

The chemical formula specified using CIF conventions. Abbreviated version of CIF standard:

  • Only recognized element symbols may be used.

  • Each element symbol is followed by a ‘count’ number. A count of ‘1’ may be omitted.

  • A space or parenthesis must separate each cluster of (element symbol + count).

  • Where a group of elements is enclosed in parentheses, the multiplier for the group must follow the closing parentheses. That is, all element and group multipliers are assumed to be printed as subscripted numbers.

  • Unless the elements are ordered in a manner that corresponds to their chemical structure, the order of the elements within any group or moiety depends on whether or not carbon is present.

  • If carbon is present, the order should be:

    • C, then H, then the other elements in alphabetical order of their symbol.

    • If carbon is not present, the elements are listed purely in alphabetic order of their symbol.

  • This is the Hill system used by Chemical Abstracts.

unit_cell_abc: (optional) NX_FLOAT (Rank: 1, Dimensions: [3]) {units=NX_LENGTH}

Crystallography unit cell parameters a, b, and c

unit_cell_alphabetagamma: (optional) NX_FLOAT (Rank: 1, Dimensions: [3]) {units=NX_ANGLE}

Crystallography unit cell parameters alpha, beta, and gamma

unit_cell_volume: (optional) NX_FLOAT {units=NX_VOLUME}

Volume of the unit cell

sample_orientation: (optional) NX_FLOAT (Rank: 1, Dimensions: [3]) {units=NX_ANGLE}

This will follow the Busing and Levy convention from Acta.Crysta v22, p457 (1967)

orientation_matrix: (optional) NX_FLOAT (Rank: 2, Dimensions: [3, 3])

Orientation matrix of single crystal sample component. This will follow the Busing and Levy convention from Acta.Crysta v22, p457 (1967)

mass: (optional) NX_FLOAT {units=NX_MASS}

Mass of sample component

density: (optional) NX_FLOAT {units=NX_MASS_DENSITY}

Density of sample component

relative_molecular_mass: (optional) NX_FLOAT {units=NX_MASS}

Relative Molecular Mass of sample component

description: (optional) NX_CHAR

Description of the sample component

volume_fraction: (optional) NX_FLOAT

Volume fraction of component

scattering_length_density: (optional) NX_FLOAT {units=NX_SCATTERING_LENGTH_DENSITY}

Scattering length density of component

unit_cell_class: (optional) NX_CHAR

In case it is all we know and we want to record/document it

Any of these values:

  • triclinic

  • monoclinic

  • orthorhombic

  • tetragonal

  • rhombohedral

  • hexagonal

  • cubic

space_group: (optional) NX_CHAR

Crystallographic space group

point_group: (optional) NX_CHAR

Crystallographic point group, deprecated if space_group present

transmission: (optional) NXdata

As a function of Wavelength

Hypertext Anchors

List of hypertext anchors for all groups, fields, attributes, and links defined in this class.

NXDL Source: