Phase Diagram of Ethane above 300 K

We have measured the melting curve of ethane from 300 to 450 K. Our results indicate that to describe all melting curve data above the triple point, it is necessary to account for a kink in the melting curve where the phase III–phase IV solid–solid transition intersects the melting curve. In the solid state, we observe some evidence for a new phase existing close to the melting curve above 300 K. We have observed that the decomposition of ethane at high pressure and temperature can be catalyzed by ruby or samarium-doped yttrium aluminum garnet at a surprisingly low temperature of 375 K.