The partial pressures of GeSn, Ge2Sn, GeSn2, and Ge3Sn have been measured above a mixture of tin, silicon, and germanium using the Knudsen effusion mass spectrometric method. Partial pressures and estimated thermal functions yield the atomization enthalpies, Delta H-a,H-o, in kJ mol(-1), of : 230+/-13 (GeSn), 490+/-22 (GeSn2), and 559+/-27 (Ge2Sn). For the molecules Ge3Sn, Ge4Sn, and SnC upper limits (for the atomization enthalpy) have been obtained as : 996+/-32, 1389+/-42, and 452+/-14, respectively.