Mole concentration means number of moles per unit volume, also called "molarity", and is used in the construction mole_concentration_of_X_in_Y, where X is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. "Brox" describes a family of chemical species consisting of inorganic bromine compounds with theexception of hydrogen bromide (HBr) and bromine nitrate (BrONO2). "Brox" is theterm used in standard names for all species belonging to the family that are represented within a given model. The list of individual species that are included in a quantity with a group chemical standard name can vary between models. Where possible, the data variable should be accompanied by a complete description of the species represented, for example, by using a comment attribute. "Inorganic bromine", sometimes referred to as Bry, describes a family of chemical species which result from the degradation of source gases containing bromine (halons, methyl bromide, VSLS) and natural inorganic bromine sources such as volcanoes, seasalt and other aerosols. Standard names that use the term "inorganic_bromine" are used for quantities that contain all inorganic bromine species including HCland ClONO2. The phrase 'expressed_as' is used in the construction A_expressed_as_B, where B is a chemical constituent of A. It means that the quantity indicated by the standard nameis calculated solely with respect to the B contained in A, neglecting all other chemical constituents of A.