Five Co-ordinated Titanium in K2Ti2O5
Five Co-ordinated Titanium in K2Ti2O5
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DOI：
10.1038/187499a0
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发表时间：
1960-08
期刊：
影响因子：
64.8
通讯作者：
S. Andersson;A. D. Wadsley
中科院分区：
文献类型：
--
作者：
S. Andersson;A. D. Wadsley
人们普遍认为，氧原子可以随机地从金属氧化物的晶格中提取出来，x射线粉末照片表明，原始化学计量物质的结构很少或没有发生改变。特别是，有证据表明，钙钛矿晶格可以在极限sabo3 - abo2.5之间持续存在，前提是六种配位离子为钛、钒、钴或铁中的一种。为了评估这一建议，我们正在检查有序的晶体结构，缺氧化合物，其中离子半径符合goldschmid2为钙钛矿结构阐明的规则。最近，Schmitz-Dumont和reckhard3报道了k2ti2o5具有低对称性的大晶胞，这可能是由于钙钛矿晶格中经常遗漏了一些氧。我们现在希望简要地报告，完整的x射线结构测定并不支持这种观点。
IT is widely believed that oxygen atoms may be extracted at random from the lattices of metallic oxides, and X-ray powder photographs have suggested that little or no modification of the structure of the original stoichiometric substance occurs. In particular, evidence has been adduced that the perovskite lattice can persist between the limitsABO3—ABO2.5, provided that the six co-ordinated ionBis one of the metals, titanium, vanadium, cobalt or iron1. In order to evaluate this proposal, we are examining the crystal structures of ordered, oxygen-deficient compounds in which the ionic radii comply with the rules enunciated by Goldschmidt2for the perovskite structure. K2Ti2O5was recently reported by Schmitz-Dumont and Reckhard3to have a large unit cell of low symmetry, and this could, perhaps, be due to the regular omission of some of the oxygens from a perovskite lattice. We now wish to report briefly that a complete X-ray structure determination does not support this view.