The equilibria involving the gaseous species SnBi, SnBi2, and SnBi3 above the condensed system Bi-Sn contained in a graphite cell have been investigated by the Knudsen effusion technique combined with mass spectrometry. Third law enthalpies for the reactions SnBin(g)=Sn(cond)+nBi(g), n=1-3, were evaluated. By combining the experimental reaction enthalpies with the appropriate thermodynamic data taken from literature, the following atomization energies, Delta(a)H(0)(o), and enthalpies of formation, Delta(f)H(298.15)(o), in kJ mol(-1), have been derived: SnBi, 191.1+/-12.0 and 317.5+/-12.0; SnBi2, 415.2+/-15.0 and 303.0+/-15.0; SnBi3, 603.4+/-18.0 and 323.0+/-18.0.