TotalComposition
ChemicalName
IUPACName
Specific form of an element defined as to isotopic composition, electronic or oxidation state, and/or complex or molecular structure. Chemical species is the macroscopic equivalent of molecular entity and refers to sets or ensembles of molecular entities.
Following nominalistic approach a species is simply a name that can point to an element name, a chemical formula or a chemical compound. So everything addressed by these classes of names can be calleded a chemical species.
ChemicalSpecies
SingleComponentComposition
Hydrogen molecule is an adequate definition of a certain molecular entity for some purposes, whereas for others it is necessary to distinguish the electronic state and/or vibrational state and/or nuclear spin, etc. of the hydrogen molecule.
Methane, may mean a single molecule of CH4 (molecular entity) or a molar amount, specified or not (chemical species), participating in a reaction. The degree of precision necessary to describe a molecular entity depends on the context.
Molecular entity is used as a general term for singular entities, irrespective of their nature, while chemical species stands for sets or ensembles of molecular entities. Note that the name of a compound may refer to the respective molecular entity or to the chemical species,
Heteronuclear
Homonuclear
An expression that provides information about the element types that constiture a molecule or a molecular substance and their number.
MolecularFormula
A chemical substance composed of atoms with the same number of protons in the atomic nucleus.
PureSubstance
A chemical entity comprises the two different ways to represents matter: as single recognizable particle entity (molecular entity) and as a composition of particle entities (substance). This distinction is not well assessed in actual chemical nomenclature, in which an element name refers to both the pure elemental substance or the atom. In the EMMO we force the adoption of a more strict categorization based on mereotopology. The class Material hosts the subclasses for which a substance can be identified without necessarily considering its nature of molecule/atom or substance (e.g. hydrocarbon is the class of both hydrocarbon molecules or gases).
ChemicalEntity
InorganicCompound
The symbol for a specific chemical element, that can stand both for an atom or a substance.
The IUPAC Gold Book defines the a chemical element both as: - a species of atoms; all atoms with the same number of protons in the atomic nucleus - a pure chemical substance composed of atoms with the same number of protons in the atomic nucleus This qualifies a chemical element as a name and not a matter obejct that can stand for an atom or a substance.
ChemicalElement
A language object following a specific nomenclature rules for defining univocal names of chemical compounds.
A chemical numenclature should not be confused with the chemical formula.
ChemicalNomenclature
HydrogenSymbol
An expression that provide information about the element type of a compound and their relative ratio.
EmpiricalFormula
OrganicCompound
PartialComposition
A language construct that provides information about the consitutents of a substance and their fractions or amounts.
ChemicalComposition
UraniumSymbol
ArgonSymbol
ChemicalMaterial
IUPACNomencalture
A symbolic construct that provides informations about the chemical proportions of the elements that constitute a chemical compound or a specific molecule.
A chemical formula may also include other symbols such as parentheses, plus and minus signs, brackets
ChemicalFormula
ElementalMaterial
ChemicalCompositionQuantity
PhysicoChemical
CategorizedPhysicalQuantity
A graphical object aimed to represent schematically the conceptual, tempral or spatial structure of another object.
Representation
A representation of objects belonging to the chemistry field.
ChemicalRepresentation
A graphical representation of a molecular structure showing the relative position in space of the atomic constituents and their bonds.
StructuralFormula
A language object that follows the syntactic rules used in the chemical field.
Chemical
ChemicalSymbolicConstruct
An expression that provides information about the element types that constiture a molecule or a molecular substance and their number, together with simple information about the connectivity of its groups by using parenthesis or by goruping element names according to its molecular structure.
CondensedFormula
Chemical Abstact Service registry number for a chemical substance from the American Chemical Society
CASRN
ChemicalSymbol
The International Chemical Identifier (InChI) textual identifier proposed by IUPAC to provide a standard encoding for databases of molecular information.
InChI
Matter of constant composition best characterized by the entities (molecules, formula units, atoms) it is composed of.
A substance is always composed of more than one molecular entity. It lays in the continuum or mesoscopic domain.
ChemicalSubstance
A chemical substance composed of many identical molecules (or molecular entities) composed of atoms from more than one element held together by chemical bonds.
ChemicalCompound