Hard-soft chemistry of Sr 1-x Ca x CrO 3-d solid solutions
Hard-soft chemistry of Sr 1-x Ca x CrO 3-d solid solutions
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Sr 1-x Ca x CrO 3-d 固溶体的硬软化学
DOI：
10.1039/c6qm00136j
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发表时间：
2017
影响因子：
7
通讯作者：
Arevalo-Lopez A
中科院分区：
文献类型：
--
作者：
Arevalo-Lopez A
Sr 1 − xCaxCrO 3 −δ（x = 0.25，0.50，0.75）固溶体是用“硬-软”技术合成的，并进行了结构表征。Sr 1 − xCaxCrO 3相在“硬”高压和高温合成下制备，然后在“软”低温条件下还原。通过粉末X射线衍射和Rietveld精修的分析表明，每种成分的还原得到两种晶体产物，具有先前在SrCrO 3 −δ中报道的6 H和15 R结构类型。类似物这些结果表明，6 H和15 R结构在Sr 1 − xCaxCrO 3 −δ中的钙含量高达x = 0.75时是稳定的，尽管在CaCrO 3 −δ中观察到不同的结构基序。Sr 1 − xCaxCrO 3 −δ相图显示，超结构形成的较低温度在x = 0.5附近具有最大值，证明Ca/Sr阳离子无序对氧空位有序性的影响。
Sr1−xCaxCrO3−δ (x = 0.25, 0.50, 0.75) solid solutions have been synthesised using the ‘hard–soft’ technique and structurally characterised. Sr1−xCaxCrO3 phases were prepared under ‘hard’ high pressure and high temperature synthesis and then reduced at ‘soft’ low temperature conditions. Analysis by powder X-ray diffraction and Rietveld refinements reveals that the reduction of each composition gives two crystalline products, with 6H and 15R structure types previously reported in SrCrO3−δ. analogues. These results demonstrate that the 6H and 15R structures are stable for very high calcium contents up to x = 0.75 in Sr1−xCaxCrO3−δ, although different structural motifs are observed for CaCrO3−δ. The Sr1−xCaxCrO3−δ phase diagram shows that the lower temperature for superstructure formation has a maximum near x = 0.5, evidencing an influence of Ca/Sr cation disorder on oxygen vacancy order.