.. auto-generated by dev_tools.docs.nxdl from the NXDL source contributed_definitions/NXsubstance.nxdl.xml -- DO NOT EDIT
.. index::
! NXsubstance (base class)
! substance (base class)
see: substance (base class); NXsubstance
.. _NXsubstance:
===========
NXsubstance
===========
**Status**:
base class, extends :ref:`NXobject`
**Description**:
.. collapse:: A form of matter with a constant, definite chemical composition. ...
A form of matter with a constant, definite chemical composition.
Examples can be single chemical elements, chemical compunds, or alloys.
For further information, see https://en.wikipedia.org/wiki/Chemical_substance.
**Symbols**:
No symbol table
**Groups cited**:
:ref:`NXnote`
.. index:: NXnote (base class); used in base class
**Structure**:
.. _/NXsubstance/name-field:
.. index:: name (field)
**name**: (optional) :ref:`NX_CHAR <NX_CHAR>`
User-defined chemical name of the substance
.. _/NXsubstance/molecular_mass-field:
.. index:: molecular_mass (field)
**molecular_mass**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_MOLECULAR_WEIGHT <NX_MOLECULAR_WEIGHT>`}
Molecular mass of the substance
.. _/NXsubstance/cas_number-field:
.. index:: cas_number (field)
**cas_number**: (optional) :ref:`NX_CHAR <NX_CHAR>`
.. collapse:: Unique numeric CAS REGISTRY number of the sample chemical content ...
Unique numeric CAS REGISTRY number of the sample chemical content
For further information, see https://www.cas.org/.
.. _/NXsubstance/cas_name-field:
.. index:: cas_name (field)
**cas_name**: (optional) :ref:`NX_CHAR <NX_CHAR>`
CAS REGISTRY name of the sample chemical content
.. _/NXsubstance/cas_uri-field:
.. index:: cas_uri (field)
**cas_uri**: (optional) :ref:`NX_CHAR <NX_CHAR>`
CAS REGISTRY URI
.. _/NXsubstance/cas_synonyms-field:
.. index:: cas_synonyms (field)
**cas_synonyms**: (optional) :ref:`NX_CHAR <NX_CHAR>`
Synonyms in the CAS system.
.. _/NXsubstance/inchi_str-field:
.. index:: inchi_str (field)
**inchi_str**: (optional) :ref:`NX_CHAR <NX_CHAR>`
.. collapse:: String InChi identifier. ...
String InChi identifier.
The InChI identifier expresses chemical structures in terms of atomic connectivity,
tautomeric state, isotopes, stereochemistry and electronic charge in order to
produce a string of machine-readable characters unique to the respective molecule.
For further information, see https://iupac.org/who-we-are/divisions/division-details/inchi/.
.. _/NXsubstance/inchi_key-field:
.. index:: inchi_key (field)
**inchi_key**: (optional) :ref:`NX_CHAR <NX_CHAR>`
.. collapse:: Condensed, 27 character InChI key. ...
Condensed, 27 character InChI key.
Hashed version of the full InChI (using the SHA-256 algorithm).
.. _/NXsubstance/iupac_name-field:
.. index:: iupac_name (field)
**iupac_name**: (optional) :ref:`NX_CHAR <NX_CHAR>`
.. collapse:: Name according to the IUPAC system (standard). ...
Name according to the IUPAC system (standard).
For further information, see https://iupac.org/.
.. _/NXsubstance/smile-field:
.. index:: smile (field)
**smile**: (optional) :ref:`NX_CHAR <NX_CHAR>`
.. collapse:: Identifier in the SMILES (Simplified Molecular Input Line Entry System) system ...
Identifier in the SMILES (Simplified Molecular Input Line Entry System) system
For further information, see https://www.daylight.com/smiles/.
.. _/NXsubstance/canonical_smile-field:
.. index:: canonical_smile (field)
**canonical_smile**: (optional) :ref:`NX_CHAR <NX_CHAR>`
Canonical version of the smiles identifier
.. _/NXsubstance/molecular_formula_hill-field:
.. index:: molecular_formula_hill (field)
**molecular_formula_hill**: (optional) :ref:`NX_CHAR <NX_CHAR>`
.. collapse:: The chemical formula specified using CIF conventions. ...
The chemical formula specified using CIF conventions.
Abbreviated version of CIF standard:107
This is the *Hill* system used by Chemical Abstracts.
* 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.
.. _/NXsubstance/cas_image-group:
**cas_image**: (optional) :ref:`NXnote`
CAS REGISTRY image
Hypertext Anchors
-----------------
List of hypertext anchors for all groups, fields,
attributes, and links defined in this class.
* :ref:`/NXsubstance/canonical_smile-field </NXsubstance/canonical_smile-field>`
* :ref:`/NXsubstance/cas_image-group </NXsubstance/cas_image-group>`
* :ref:`/NXsubstance/cas_name-field </NXsubstance/cas_name-field>`
* :ref:`/NXsubstance/cas_number-field </NXsubstance/cas_number-field>`
* :ref:`/NXsubstance/cas_synonyms-field </NXsubstance/cas_synonyms-field>`
* :ref:`/NXsubstance/cas_uri-field </NXsubstance/cas_uri-field>`
* :ref:`/NXsubstance/inchi_key-field </NXsubstance/inchi_key-field>`
* :ref:`/NXsubstance/inchi_str-field </NXsubstance/inchi_str-field>`
* :ref:`/NXsubstance/iupac_name-field </NXsubstance/iupac_name-field>`
* :ref:`/NXsubstance/molecular_formula_hill-field </NXsubstance/molecular_formula_hill-field>`
* :ref:`/NXsubstance/molecular_mass-field </NXsubstance/molecular_mass-field>`
* :ref:`/NXsubstance/name-field </NXsubstance/name-field>`
* :ref:`/NXsubstance/smile-field </NXsubstance/smile-field>`
**NXDL Source**:
https://github.com/FAIRmat-NFDI/nexus_definitions/tree/fairmat/contributed_definitions/NXsubstance.nxdl.xml