Crystallographic properties of Cu₂O and CuO⁴¹.

Parameters		Cu2O	CuO
Structure: Cu(i)-yellowish, Cu(ii)-greyish black, O-red
Unit cell		a = b = c = 4.26 Å	a = 4.6837 Å, b = 3.4226 Å, c = 5.1288 Å
		α = β = γ = 90°	α, γ = 90°, β = 99.54°
Space group		Pn3̄m (224)	C2/c (15)
Bond length, Å	Cu–O	1.849	1.96
	O–O	3.68	2.62
	Cu–Cu	3.012	2.90
Cell volume, Å3		77.83	81.08
Formula weight		143.14	79.57
Density, g cm−3		5.749–6.140	6.515
Melting point, °C		1235	1201