quantitykind:MolarVolume
The molar volume, symbol $V_m$, is the volume occupied by one mole of a substance (chemical element or chemical compound) at a given temperature and pressure. It is equal to the molar mass ($M$) divided by the mass density ($\rho$). It has the SI unit cubic metres per mole ($m^{1}/mol$). For ideal gases, the molar volume is given by the ideal gas equation: this is a good approximation for many common gases at standard temperature and pressure. For crystalline solids, the molar volume can be measured by X-ray crystallography.