It crystallizes in a cubic rocksalt lattice like sodium chloride, with octahedral cation and anion centers. It occurs naturally as the rare mineral monteponite. Cadmium oxide can be found as a colorless amorphous powder or as brown or red crystals.Cadmium oxide is an n-type semiconductor[13] with a band gap of 2.18 eV (2.31 eV) at room temperature (298 K).