Gas Constant b adjusts for the volume occupied by the gas particles. It is a correction for finite molecular size and its value is the volume of one mole of the atoms or molecules. And is denoted by b. Gas Constant b is usually measured using the Cubic Meter per Mole for Molar Magnetic Susceptibility. Note that the value of Gas Constant b is always positive. Typically, the value of Gas Constant b is greater than 0.