Why Diamond has higher melting point than Silicon Carbide?
Neither diamond nor silicon carbide melts at standard pressures.
However, they both sublimate at high temperatures.
Both diamond and silicon carbide have a tetrahedral covalent network structure.
Diamond does not melt at ordinary pressures. It converts to graphite and sublimates at about 3680 °C.
Silicon carbide sublimates at about 2700 °C.
The difference appears to be caused by the differences in bond lengths and bond strengths.
Silicon carbide has a
Diamond has a much shorter
Thus, it takes more energy to vaporize diamond, and diamond has the higher sublimation temperature.