Table 2.

Base units defined in SBML. These symbols are predefined values of type UnitSId (Section 3.1.9). All are names of base or derived SI units (Bureau International des Poids et Mesures, 2006), except for “ avogadro”, “ dimensionless” and “ item”, which are SBML additions. The unit “ dimensionless” is intended for cases where a quantity is a ratio whose units cancel out, the unit “ avogadro” is the unit “ dimensionless” multiplied with Avogadro’s number, and “ item” is used for expressing such things as “N items” when “mole” is not an appropriate unit. The gram and litre are not strictly part of SI; however, they are frequently used in SBML’s areas of application and therefore are included as predefined unit identifiers. (The standard SI unit of mass is the kilogram, and volume in SI is defined in terms of cubic metres.) Comparisons of these values, like all values of type UnitSId, must be performed in a case-sensitive manner.

ampere	farad	joule	lux	radian	volt
avogadro	gram	katal	metre	second	watt
becquerel	gray	kelvin	mole	siemens	weber
candela	henry	kilogram	newton	sievert
coulomb	hertz	litre	ohm	steradian
dimensionless	item	lumen	pascal	tesla