Фазовая диаграмма системы Mn-Se

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Mn-Se (Manganese-Selenium) M. Lasocka The Mn-Se system has not been investigated over the entire concentration range. The only available experimental data are for the intermediate phases MnSe and MnSe2. Because the Mn-Se system is homologous with the Mn-Te system, liquid- liquid immiscibility in Mn-rich melts may be expected. The most probable speculative drawing of the Mn-Se equilibrium diagram is given here. The solid solubility of Se in (gMn) is >5 at.% Se [Brandes] (not shown in the assessed diagram), and the solubility of Se in (aMn) and (bMn) is negligible [ Shunk, Brandes]. No information regarding the solubility of Mn in (Se) is available. The homogeneity ranges of MnSe and MnSe2 are very small or are at least below the detection limit of X-ray diffraction techniques [69Wie]. The structure of MnSe depends on the method of preparation. Four metastable modifications are reported. bMnSe (sphalerite type) and gMnSe (wurtzite type) may be obtained at normal pressure and at 25 C. The stable form in these conditions is aMnSe, with a rock-salt-type structure. At about 90 kbar and 25 C, a high-pressure modification of MnSe (NiAs type) is obtained. At normal pressure and below -48 C, low-temperature monoclinic MnSe is obtained [72Cem, 74Cem]. The vaporization of solid MnSe was studied by [68Wie] at low pressure from 10- 8 to 10-4 bar. Both MnSe and MnSe2 are antiferromagnetic. The N‚el temperature is 150 K for MnSe [68Car] and 100 K for MnSe2 [68Car]. 67Van: V.G. Vanyarkho, V.P. Zlomanov, and A.V. Novoselova, Izv. Akad. Nauk SSSR, Neorg. Mater., 3, 1276-1277 (1967) in Russian. 68Car: F.M.A. Carpay, Philips Res. Rep., Suppl. 10 (1968). 68Coo: W.R. Cook, Jr., J. Am. Ceram. Soc., 51, 518-520 (1968). 68Wie: H. Wiedemeier and W.J. Goyette, J. Chem. Phys., 48, 2936-2941 (1968). 69Van: V.G. Vanyarkho, V.P. Zlomanov, A.V. Novoselova, and V.N. Fokin, Izv. Akad. Nauk SSSR, Neorg. Mater., 5, 1699-1702 (1969) in Russian. 69Wie: H. Wiedemeier and A.G. Sigai, High-Temp. Sci., 1, 18-25 (1969). 72Cem: L. Cemic and A. Neuhaus, High Temp.-High Press., 4, 97-99 (1972) in German. 74Cem: L. Cemic and A. Neuhaus, High Temp.-High Press., 6, 203-215 (1974) in German. Submitted to the APD Program. Complete evaluation contains 1 figure, 5 tables, and 26 references. Special Points of the Mn-Se System