Standard molar Gibbs free energy of formation of ternary oxides Pb5CrO8(s), Pb2CrO5(s), and PbCrO4(s) were determined by measuring equilibrium oxygen partial pressures over relevant phase fields using manometry and solid oxide electrolyte based emf methods and are given by: Delta(f)G(m)(o)Pb(5)CrO(8) (s) 0.55/(kJ . mol(-1)) = -1809.4 + 0.6845(T/K) (837 <= T/K <= 1008) Delta(f)G(m)(o)Pb(2)CrO(5)(s) 0.30/(kJ . mol(-1)) = -1161.3 + 0.4059(T/K) (859 <= T/K <= 1021) Delta(f)G(m)(o)PbCrO(4)(s) 0.17/(kJ . mol(-1)) = -909.8 + 0.3111 (T/K) (863 <= T/K <= 1093), (C) 2009 Elsevier Ltd. All rights reserved.