def molar_volume_Le_Bas(MW, organic = True):
    """
    Return the molar volume [m³/mol] from the molecular weight
    source : (HNS-MS)

    Parameters
    ----------
    MW : Molecular weight [kg/mol]
    organic : Chemical type, True if organic, the default is True.


    """
    if organic:
        return 4.9807  * (MW/1000)**0.6963
    else:
        return 2.8047 * (MW/1000)**0.651