Rosales Ivonne, Chavira Elizabeth, Orozco Eligio, Bucio Lauro
Acta Crystallogr Sect E Struct Rep Online. 2009 Jun 6;65(Pt 7):i49-i50. doi: 10.1107/S1600536809020467.
Y(0.76)Ho(0.24)FeGe(2)O(7) (yttrium holmium iron digermanate) was synthesized by solid-state reaction at 1573 K. This thortveitite-like compound presents a crystallographic group-subgroup isotranslational (klassengleiche) relation with some other pyrogermanates, such as FeInGe(2)O(7), In(1.08)Gd(0.92)Ge(2)O(7) and InYGe(2)O(7), which are configurationally isotypic with the Sc(2)Si(2)O(7) thortveitite structure first reported by Zachariasen [(1930 ▶). Z. Kristallogr.73, 1-6]. Holmium cations share with yttrium the 4f Wyckoff position at the center of a seven-coordinated pentagonal bipyramid, while Fe atoms also occupy one site with Wyckoff position 4f at the center of the octahedron. All these sites have the point symmetry C(1). Two types of Ge(2)O(7) diorthogroups with point symmetry C(1h) are present in the structure, each one of them defining a layer type which alternates with the other. These diorthogroups have their tetrahedral groups in an eclipsed conformation.
Y(0.76)Ho(0.24)FeGe₂O₇（钇钬铁二锗酸盐）通过在1573 K下的固态反应合成。这种类钪钇石化合物与其他一些焦锗酸盐呈现晶体学群-子群同平移（类质同象）关系，如FeInGe₂O₇、In₁.₀₈Gd₀.₉₂Ge₂O₇和InYGe₂O₇，它们在构型上与Zachariasen首次报道的Sc₂Si₂O₇钪钇石结构同型[（1930年▶）。《晶体学报》73卷，1 - 6页]。钬阳离子与钇共享位于七配位五角双锥中心的4f Wyckoff位置，而铁原子也占据八面体中心具有Wyckoff位置4f的一个位点。所有这些位点具有点群C₁。结构中存在两种点群为C₁h的Ge₂O₇双正交群，它们各自定义一种层型并相互交替。这些双正交群的四面体群处于重叠构象。
