Synthese,Kristallstruktur und thermischer Abbau von Fluoroaluminaten der Zusammensetzung (NH4)[M(H2O)6][AlF6] (M = Zn,Ni), [Zn(H2O)6][AlF5(H2O)] und (PyH)4[Al2F10] · 4 H2O |
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Authors: | B Adamczyk S I Troyanov M Schneider E Kemnitz |
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Abstract: | Synthesis, Crystal Structure and Thermal Behaviour of Fluoroaluminates of the Composition (NH4)M(H2O)6](AlF6) (M = Zn, Ni), Zn(H2O)6]AlF5(H2O)], and (PyH)4Al2F10] · 4 H2O Four new fluoroaluminates were obtained from fluoroacidic solutions of respective metal salts. The compounds of zinc ( I a : P21/c, a = 12.688(3), b = 6.554(1), c = 12.697(3) Å, β = 95.21(3)°, V = 1051.5(4) Å3, Z = 4) and nickel ( I b : P21/c, a = 12.685(3), b = 6.517(1), c = 12.664(2)Å, β = 94.55(2)°, V = 1043.6(4) Å3, Z = 4) are isotypic and represent a new structure type consisting of two different cations, NH4+ and M(H2O)6]2+ and AlF6]3–‐anions. Zn(H2O)6]AlF5(H2O)] ( II : C2/m, a = 10.769(2), b = 13.747(3), c = 6.487(1)Å, β = 100.02(3)°, V = 945.7(3) Å3, Z = 4) is characterized by a H2O/F‐disorder in the AlF5(H2O)]‐octahedra in two trans positions. In (PyH)4Al2F10] · 4 H2O ( III : Cmc21, a = 15.035(3), b = 20.098(4), c = 12.750(4) Å, V = 5364(2) Å3, Z = 8), bioctahedral Al2F10]4– anions have been found for the first time. The structures are described and discussed in comparison. The new compounds were used as precursors in order to obtain new AlF3‐phases. However, the thermal decomposition did not result in the formation of any new metastable AlF3‐phase. Instead, phase mixtures of either α‐AlF3 and β‐AlF3 or AlF3 and MF2 were obtained. |
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Keywords: | Fluoroaluminates Crystal structure Thermal behaviour |
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