Dimensionless multiplier in real gas equation of state which describes the deviation of a real gas from ideal gas behavior:

Z = \frac{p V}{\nu R T}

where


fluid pressure	fluid volume	fluid temperature	gas constant	Amount of substance

It is related to gas compressibility as:

Z(p) = \frac{Z_0}{p_0} \cdot p \cdot \exp \left[ - \int_{p_0}^p c(p) dp  \right]

c_g = - \frac{1}{V} \frac{dV}{dp} = - \frac{d}{dp} \left( \ln V \right) \rightarrow \ln \frac{V}{V_0} = - \int_{p_0}^p c(p) dp

Substituting from into one arrives to .

See also