Résumé : A number of gaseous ternary oxides have been identified by mass spectrometry, while vaporizing MgO, CaO, SrO and SnO2+Sn from Mo and W crucibles. The stabilities of the gaseous molecules SrMoO3, CaWO3, SrWO3, MgMoO4, CaMoO4, SrMoO4, MgWO4, CaWO4, SrWO4, SnWO4 and Sn2WO5, were deduced from the measurements.