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Sulfate und Hydrogensulfate des Erbiums: Er(HSO4)3-I, Er(HSO4)3-II, Er(SO4)(HSO4) und Er2(SO4)3

1998; Wiley; Volume: 624; Issue: 8 Linguagem: Alemão

10.1002/(sici)1521-3749(199808)624

1521-3749

Mathias S. Wickleder,

Fluoride Effects and Removal

Aus einer Lösung von Er2(SO4)3 in konz. H2SO4 kristallisiert bei 250 °C Er(HSO4)3-I (orthorhombisch, Pbca, a = 1195,0(1) pm, b = 949,30(7) pm, c = 1644,3(1) pm) in Form hellrosa säuliger Kristalle. Aus 85%iger H2SO4-Lösung, der Na2SO4 zugesetzt wurde, erhält man bei 250 °C hellrosa quaderförmige Kristalle von Er(HSO4)3-II (monoklin, P21/n, a = 520,00(5) pm, b = 1357,8(1) pm, c = 1233,4(1) pm, β = 92,13(1)°) und bei ca. 60 °C Kristalle gleicher Farbe von Er(SO4)(HSO4) (monoklin, P21/n, a = 545,62(6) pm, b = 1075,6(1) pm, c = 1053,1(1) pm, β = 104,58(1)°). In beiden Hydrogensulfaten ist Er3+ von acht Sauerstoffatomen umgeben. In Er(HSO4)3-I werden Schichten von HSO4–-Tetraedern ausschließlich über Wasserstoffbrücken zusammengehalten, während bei Er(HSO4)3-II die Polyeder dreidimensional vernetzt sind. In der Kristallstruktur von Er(SO4)(HSO4) ist Er3+ von sieben Sauerstoffatomen umgeben, die zu vier SO42–- und drei HSO4–-Gruppen gehören. Das wasserfreie Sulfat, Er2(SO4)3, ist nicht aus H2SO4-Lösungen zugänglich, kann jedoch einkristallin aus einer NaCl-Schmelze erhalten werden. Die Koordinationszahl von Er3+ in Er2(SO4)3 (orthorhombisch, Pbcn, a = 1270,9(1) pm, b = 913,01(7) pm, c = 921,67(7) pm) ist sechs, die oktaedrischen Koordinationspolyeder sind über alle Ecken mit SO42–-Tetraedern verknüpft. Sulfates and Hydrogensulfates of Erbium: Er(HSO4)3-I, Er(HSO4)3-II, Er(SO4)(HSO4), and Er2(SO4)3 Rod shaped light pink crystals of Er(HSO4)3-I (orthorhombic, Pbca, a = 1195.0(1) pm, b = 949.30(7) pm, c = 1644.3(1) pm) grow from a solution of Er2(SO4)3 in conc. H2SO4 at 250 °C. From slightly diluted solutions (85%) which contain Na2SO4, brick shaped light pink crystals of Er(HSO4)3-II (monoclinic, P21/n, a = 520.00(5) pm, b = 1357.8(1) pm, c = 1233.4(1) pm, β = 92.13(1)°) were obtained at 250 °C and crystals of the same colour of Er(SO4)(HSO4) (monoclinic, P21/n, a = 545.62(6) pm, b = 1075.6(1) pm, c = 1053.1(1) pm, β = 104.58(1)°) at 60 °C. In both hydrogensulfates, Er3+ is surrounded by eight oxygen atoms. In Er(HSO4)3-I layers of HSO4– groups are connected only via hydrogen bridges, while Er(HSO4)3-II consists of a threedimensional polyhedra network. In the crystal structure of Er(SO4)(HSO4) Er3+ is sevenfold coordinated by oxygen atoms, which belong to four SO42–- and three HSO4–-tetrahedra, respectively. The anhydrous sulfate, Er2(SO4)3, cannot be prepared from H2SO4 solutions but crystallizes from a NaCl-melt. The coordination number of Er3+ in Er2(SO4)3 (orthorhombic, Pbcn, a = 1270.9(1) pm, b = 913.01(7) pm, c = 921.67(7) pm) is six. The octahedral coordinationpolyhedra are connected via all vertices to the SO42–-tetrahedra.