Martínez-Lope M J, Alonso J A, Retuerto M, Fernández-Díaz M T
Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid, Spain.
Inorg Chem. 2008 Apr 7;47(7):2634-40. doi: 10.1021/ic701969q. Epub 2008 Feb 27.
RVO3 perovskites have been prepared in the widest range of R (3+) ionic size, from LaVO3 to LuVO3. Pure polycrystalline samples have been obtained by a citrate technique leading to reactive RVO4 precursors, followed by thermal treatments in a reducing H2/N2 (15/85%) flow to stabilize V(3+) cations. These oxides have been studied at room temperature by high-resolution neutron powder diffraction to follow the evolution of the crystal structures along the series. The distortion of the orthorhombic perovskite (space group Pbnm), characterized by the tilting angle of the VO6 octahedra, progressively increases from La to Lu due to simple steric factors. Additionally, all of the perovskites show a subtle distortion of the VO6 octahedra which significantly increases from La to Tb, and then slightly decreases for the last terms of the series. The stability of the crystal structure is also discussed in light of bond-valence arguments.
RVO₃钙钛矿已在从LaVO₃到LuVO₃的最广泛的R(3+)离子尺寸范围内制备出来。通过柠檬酸盐技术获得了纯多晶样品，该技术产生了活性RVO₄前驱体，随后在还原性H₂/N₂(15/85%)气流中进行热处理以稳定V(3+)阳离子。这些氧化物在室温下通过高分辨率中子粉末衍射进行了研究，以追踪沿该系列晶体结构的演变。正交钙钛矿（空间群Pbnm）的畸变，以VO₆八面体的倾斜角为特征，由于简单的空间因素，从La到Lu逐渐增加。此外，所有钙钛矿都显示出VO₆八面体的细微畸变，从La到Tb显著增加，然后在该系列的最后几项中略有下降。还根据键价观点讨论了晶体结构的稳定性。
