Minor issue, but could you please add R-number aliases for a few more fluids?
R50 - Methane
R170 - Ethane
R600 - Butane
R704 - Helium
R718 - Water
R720 - Neon
R728 - Nitrogen
R729 - Air
R732 - Oxygen
R740 - Argon
R1150 - Ethylene
R1270 - Propylene