35. Manganese vapor pressures in equilibrium with manganese-iron-nickel solid solutions: J H Smith, H W Paxton, C L McCabe,J Phys Chem,68, June 1964, 1345–1354

Abstract

The high temperature vaporization of Nd3−xS4(s) was investigated by the mass loss Knudsen effusion method over the temperature range 1952–2229 K. NdS1.38 vaporizes congruently according to 1.(I) NdS1.38(s) = NdS(g) + 0.38S(g) and2.(II) NdS1.38(s) = Nd(g) + 1.38S(g). The equilibrium partial pressures are as follows: LnPs(atm) = −63 373(±439)T + 15.67(±0.21); LnPNd(atm) = − 62 802 (± 368) + 15.64(± 0.18); LnPNdS(atm) = − 66285(± 807)T + 17.09 (±0.39). The second-law thermodynamic values are as follows: ΔH298o = 191.6 (±4) cal mol−1, ΔS298o = 58.8(±2) cal mol−1 K−1 for reaction (I); ΔH298o = 304.5(±4) kcal mol−1, ΔSo298 = 81.8(±2) cal mol−1 K−1 for reaction (II). The third-law values are as follows: ΔH298o = 189.4(±2) kcal mol−1 for reaction (I), ΔH298o = 302.3(±2) kcal mol−1 for reaction (II).