Two anionically derivatized scandium oxoselenates(IV): ScF[SeO3] and Sc2O2[SeO3]
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- 作者：Stefan Greiner ; Sheng-Chun Chou ; Thomas Schleid ; schleid@iac.uni-stuttgart.de
- 关键词：Scandium ; Oxoselenates(IV) ; Fluorides ; Crystal structure ; Stereochemical lone-pair activity ; Raman spectroscopy
- 刊名：Journal of Solid State Chemistry
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：246
- 期：Complete
- 页码：160-166
- 全文大小：1146 K
- 卷排序：246
文摘
Scandium fluoride oxoselenate(IV) ScF[SeO3] and scandium oxide oxoselenate(IV) Sc2O2[SeO3] could be synthesized through solid-state reactions. ScF[SeO3] was obtained phase-pure, by reacting mixtures of Sc2O3, ScF3 and SeO2 (molar ratio: 1:1:3) together with CsBr as fluxing agent in corundum crucibles embedded into evacuated glassy silica ampoules after firing at 700 °C for seven days. Sc2O2[SeO3] first emerged as by-product during the attempts to synthesize ScCl[SeO3] following aforementioned synthesis route and could later be reproduced from appropriate Sc2O3/SeO3 mixtures. ScF[SeO3] crystallizes monoclinically in space group P21/m with a=406.43(2), b =661.09(4), c=632.35(4) pm, β=93.298(3)° and Z=2. Sc2O2[SeO3] also crystallizes in the monoclinic system, but in space group P21/n with a=786.02(6), b=527.98(4), c=1086.11(8) pm, β=108.672(3)° for Z=4. The crystal structures of both compounds are strongly influenced by the stereochemically active lone pairs of the ψ1-tetrahedral [SeO3]2– anions. They also show partial structures, where the derivatizing F− or O2− anions play an important role. For ScF[SeO3] chains of the composition {[FSc2/2]2+∞1} form from connected [FSc2]5+ dumbbells, while [OSc3]7+ pyramids and [OSc4]10+ tetrahedra units are condensed to layers according to {[O2Sc2]2+∞2} in Sc2O2[SeO3].