Vaporization studies on {(1 - x)Mn + xTe} samples. where x = (0.549, 0.599, 0.718, 0.720, and 0.741) were conducted by Knudsen effusion mass spectrometry. Experiments with the first two samples yielded vapor pressures for the two-phase region (manganese ditelluride + manganese monotelluride) in the temperature range 650 K to 750 K: 1g{p(Te-2)/Pa} = -(10010 +/-98)/(K/T) + (13.421 +/- 0.140). The vaporization reaction MnTe1.87(s) = MnTe1.03(s) + 0.42Te(2)(g) was evaluated: Delta(r)H(m)degrees (298.15 K) = (80.7 +/- 2.2) kJ(.)mol(-1). Combining this with literature values for Delta(f)H(mdegrees) (298.15 K) for Te-2(g) and the MnTe phase, we deduced that Delta(f)H(m)degrees (MnTe1.87, s, 298.15K ) = -(111.4 +/-7.2) kJ(.)mol(-1). The last three samples, corresponding to the two-phase region (manganese ditelluride + tellurium) were subjected to long, predominantly isothermal, experiments. They served to show that the MnTe2 phase exists from x(Te) = (0.651 to 0.670) at 650 K less than or equal to T less than or equal to 675 K, besides yielding p(Te-2) at various x(Te)s across the homogeneity range of MnTe2, and confirming the reliability of the vapor pressure equation given above. These results also rendered it possible to deduce Delta(f)H(m)degrees (298.15 K) for the MnTe2 phase corresponding to the formulas for the Te-rich and Mn-rich boundaries: Delta(f)H(m)degrees (MnTe2.03, s, 298.15 K) = -121.6 kJ(.)mol(-1). and Delta(f)H(m)degrees (MnTe1.87, s. 298.15 K) = -120.2 kJ(.)mol(-1). The latter, in combination with Delta(r)H(m)degrees (298.15 K) and Delta(f)H(m)degrees (Te2, g, 298.15 K), yielded Delta(f)H(m)degrees (MnTe1.03, s. 298.15 K) = -108.0 kJ(.)mol(-1).