Ce10[Si10O9N17]Br, Nd10[Si10O9N17]Br and Nd10[Si10O9N17]Cl oxonitridosilicate halides with a new layered structure type |
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Authors: | Alexandra Lieb |
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Institution: | Department Chemie und Biochemie, Lehrstuhl für Anorganische Festkörperchemie, Ludwig-Maximilians-Universität, Butenandtstraße 5-13 (D), D-81377 München, Germany |
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Abstract: | The isotypic oxonitridosilicate halides Ce10Si10O9N17]Br, Nd10Si10O9N17]Br and Nd10Si10O9N17]Cl were obtained by the reaction of the respective lanthanide metals, their oxides and halides with “Si(NH)2” in a radiofrequency furnace at temperatures around 1800 °C, using CsBr, resp. CsCl, as a flux. The crystal structures were determined by single-crystal X-ray diffraction (Pbam, no. 55, Z=2; Ce/Br: a=10.6117(9) Å, b=11.2319(10) Å, c=11.688(8) Å, R1=0.0356; Nd/Br: a=10.523(2) Å, b=11.101(2) Å, c=11.546(2) Å, R1=0.0239; Nd/Cl: a=10.534(2) Å, b=11.109(2) Å, c=11.543(2) Å, R1=0.0253) and represent a new layered structure type. The structure refinements were performed utilizing an O/N-distribution model according to Paulings rules, i.e. nitrogen was positioned on all bridging sites and mixed O/N-occupation was assumed on the terminal sites resulting in charge neutrality of the compounds. The layers consist of condensed SiN2(O/N)2] and SiN3(O/N)] tetrahedra of Q2 and Q3 type. The chemical composition of the compounds was derived from chemical analyses for Nd10Si10O9N17]Br and electron probe micro analyses (EPMA) for all three compounds. The results of IR spectroscopic investigations are reported. |
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Keywords: | Cerium Neodymium Chloride Bromide Oxonitridosilicate Crystal structure Electron probe micro analysis (EPMA) |
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