In this study we investigated the subsolidus phase equilibria in the HoO–ZrO–MoO system and discovered the double molybdate HoZr(MoO). The Rietveld method was used to refine the structures of the low- and high-temperature phases. The title compound is isostructural to ErZr(MoO) double molybdate and crystallizes in the monoclinic space group 2, but rearranges to rhombic (space group 2) at temperatures above 100°С. HoZr(MoO) exhibits negative thermal expansion in the high temperature region (αV = −3.9 × 10 °C). Theoretical calculations using bond valence sum maps method suggest that this compound may have three-dimensional O conductivity with relatively low energy barriers (0.588 eV).

中文翻译：

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Ho2Zr(MoO4)5 — 一种新型的负热膨胀双钼酸盐

在这项研究中，我们研究了 HoO-ZrO-MoO 体系中的亚固相线相平衡，并发现了双钼酸盐 HoZr(MoO)。 Rietveld 方法用于细化低温相和高温相的结构。标题化合物与 ErZr(MoO) 双钼酸盐同构，在单斜晶系空间群 2 中结晶，但在温度高于 100°С 时重排成斜方晶系（空间群 2）。 HoZr(MoO)在高温区域(αV = -3.9 × 10 °C)表现出负热膨胀。使用键价和图方法的理论计算表明，该化合物可能具有三维O电导率和相对较低的能垒（0.588 eV）。