Фазовая диаграмма системы B-O

К оглавлению: Другие диаграммы (Others phase diargams)


B-O (Boron-Oxygen) Editor No equilibrium diagram is available for the B-O system, but a tentative T-P diagram for B2O3 is shown. A number of suboxides of B have been reported in the literature, and there is substantial disagreement on the stoichiometry of the most B-rich suboxide. This oxide has been conclusively identified as B13O2 from [66Kon] (or B6O, according to [62Riz]). Other oxides confirmed are B2O [ 41Ray], BO [40Zin, 41Ray, 55War], and B2O3. Early reports [44Hen, 52Ber] indicated B2O3 to be hexagonal. B2O3 is commonly available only in the glassy or vitreous state. [61Mac] reported the preparation of two pressure-dependent, crystalline forms of B2O3-hexagonal aB2O3 and monoclinic bB2O3-by high- pressure crystallization of the glassy B2O3 phase. A tentative pressure- temperature diagram was reported for the a and b forms of B2O3, with a triple point at ~1100 C and 70 000 atm [61Mac]. The bB2O3 phase could be metastably retained at ambient temperature and pressure, because of sluggish b <259> a transformation kinetics. [68Pre] confirmed the formation of bB2O3 at 65 kbar and 1100 C, but reported an orthorhombic structure for this phase.-P.R.S. 40Zin: E. Zintl, W. Morawietz and E. Gastinger, Z. Anorg. Allg. Chem., 245, 8- 11 (1940) in German. 41Ray: R.C. Ray and P.C. Sinka, J. Chem. Soc., 742-744 (1941). 44Hen: S.B. Hendricks, J. Wash. Acad. Sci., 34, 241 (1944). 52Ber: S.V. Berger, Acta Crystallogr., 5, 389 (1952). 55War: T. Wartik and E.F. Apple, J. Am. Chem. Soc., 77, 6400-6401 (1955). 61Mac: J.D. Mackenzie and W.F. Claussen, J. Am. Ceram. Soc., 44, 79-81 (1961). 62Riz: H.F. Rizzo, W.C. Simmons, and H.O. Bielstein, J. Electrochem. Soc., 109, 1079-1082 (1962). 66Kon: Y.D. Kondrashev, G.S. Markevich, and L.Y. Markovskii, Russ. J. Inorg. Chem., 11(6), 780-781 (1966). 68Pre: C.T. Prewitt and R.D. Shannon, Acta Crystallogr. B, 24, 869-874 (1968). 70Gur: G.E. Gurr, P.W. Montgomery, C.D. Knutson, and B.T. Gorner, Acta Crystallogr. B, 26(7), 906-915 (1970). 1