CaC2
Ca - Group 2 metal
C - Group 4 non-metal
It is an ionic compound. :)
Explanation: Ionic compounds has a giant lattice structure with strong electrostatic forces of attraction between ions of Metal and Non-Metal. This compound require a large amount of energy/heat to overcome.
Covalent compounds has a simple molecular structure with weak intermolecular bonds with Non-metals only. This compound requires little energy/heat to overcome.