An equation of state in reference to gases which applies a correction to the van der Waals equation: {P + (n²a /[T(V + c )²])} (V – nb ) = nRT, where P is the pressure, T the temperature, V the volume of the gas, n the number of moles in the gas, R the gas constant, a depends only on temperature, b is a constant, and c is a function of a and b.