For Which Of The Following Substances Fh0 Is Zero?

For Which Of The Following Substances Fh0 Is Zero? Ne(g) is monoatomic (inert gas). Therefore heat of formation is zero. For which of the following substances enthalpy of formation is zero? The enthalpy of both graphite and diamond is taken to be zero, being elementary substances. For which of the following substances does Δhof 0?