In this study, the standard Gibbs free energy of formation of MgSb2O4 has been determined by means of the solid-oxide electrolyte EMF technique. A pure-oxygen reference electrode was applied for the first time to this system in an oxygen concentration cell. The EMF values, temperature and the prevailing pressure of the following galvanic cell were measured: (-)Pt, Re, Sb(l), MgO(s), MgSb2O4(s)vertical bar YSZ vertical bar O-2(g), Pt(+). The standard Gibbs free energy of the virtual cell reaction 2Sb(l) + 3/2O(2)(g) + MgO(s) = MgSb2O4(s) was determined to be: Delta(r)G degrees/(kJ . mol(-1)) +/- 2.97 = -734.96 + 0.2645T/K (906 < T/K < 1148). The standard Gibbs free energy of formation of solid MgSb2O4 from its pure component oxides Sb2O3(l) + MgO(s) = MgSb2O4(s) was determined to be: Delta(f)G degrees(MgSb2O4)/(kJ . mol(-1)) +/- 3.00 = -52.75 + 0.0253T/K (929 <= T/K <= 1148). The standard Gibbs free energy of formation of solid MgSb2O4 from the elements Mg(l) + 2Sb(l) + 2O(2)(g) - MgSb2O4(s) was determined to be: Delta(f')G degrees(MgSb2O4)/(kJ . mol(-1)) +/- 18.2 = -1392 + 0.4055T/K (973 <= T/K <= 1148). (C) 2014 Elsevier Ltd. All rights reserved.