Ions with the suffix -onium, indicating cations with coordination number 4 of the type RxA+ which are analogous to QUATERNARY AMMONIUM COMPOUNDS (H4N+). Ions include phosphonium R4P+, oxonium R3O+, sulfonium R3S+, chloronium R2Cl+
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
Inorganic or organic compounds that contain sulfur as an integral part of the molecule.
Organic compounds that have a relatively high VAPOR PRESSURE at room temperature.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.