Vaporization studies on Mn-Te samples of initial compositions 49.6 and 54.9 at. % Te were conducted by Knudsen effusion mass spectrometry. Both these samples on continuous vaporization reached the congruently effusing compositions (CECs) approximate to 50 at. % Te. Vaporization chemistry around this composition was studied from 1194 to 1343 K to examine the effects associated with the reported phase transitions in MnTe(s) at 1228 (alpha <-> beta), 1293 (beta<->gamma), and 1323 K (gamma<->delta). Among these, only the alpha<->beta phase transition showed significant effects. During the phase transition, the vapor phase was relatively richer in manganese in the increasing temperature direction (i.e., as the sample was heated from T less than or equal to 1203 K to T greater than or equal to 1238 K) and was relatively richer in tellurium in the decreasing temperature direction (i.e., as the sample was cooled from T greater than or equal to 1238 K to T less than or equal to 1218 K). Evidence for a slight variation in the CEC with temperature was also obtained but was distinguishable from the effects associated with the alpha<->beta phase transition. From the results obtained in four series of experiments, the partial pressures of Mn(g), Te(g), and Te-2(g) were deduced, and by neglecting the variations in the CECs with temperature, the enthalpy changes for the following Vaporization reactions during congruent effusion were evaluated: MnTe(s) = Mn(g) + 0.5Te(2)(g), Delta(r)H degrees(m)(298.15K) = 463.6 +/- 2.1 kJ mol(-1); MnTe(s) Mn(g) + Te(g), Delta(r)H degrees(m)(298.15K) = 592.4+/-2.3 kJ mol(-1) MnTe(s) = Mn (g) + yTe(g) + (1 - y)/2Te(2)(g), Delta(r)H degrees(m) (298.15 K) = 554.0 +/- 4.6 kJ mol(-1), y(mean) approximate to 0.7. These results yielded Delta(f)H degrees(m)(MnTe,s,298.15K) = - 99.2 +/- 6.8 kJ mol(-1). An equation for the total vapor pressure during congruent effusion of MnTe(s), valid for the temperature range from 1194 to 1343 K was obtained: log(P/Pa) = - (14539 +/- 273)/(T/K) + (11.159 +/-0.222).