The structure of rubidium trioxalatochromate (III), Rb3[Cr(C2O4)3].xH2O, and its relation to the corresponding potassium and ammonium structures
The structure of rubidium trioxalatochromate (III), Rb3[Cr(C2O4)3].xH2O, and its relation to the corresponding potassium and ammonium structures
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三草酸铬酸铷 (III) Rb3[Cr(C2O4)3].xH2O 的结构及其与相应钾和铵结构的关系
DOI：
10.1107/s0365110x52001398
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发表时间：
1952
期刊：
影响因子：
--
通讯作者：
F. Schoening
中科院分区：
文献类型：
--
作者：
J. Niekerk;F. Schoening
通过对比Weissenberg照片、Harker截面和Patterson投影，证明了化合物Rb_3 [Cr（C~（04））_3]. xH 2 O和相应的钾化合物是同种型。相应的铵化合物具有不同的结构。它表明，这种结构上的差异是不是由于阳离子的大小不同，但它可能是由于铵离子形成四面体定向的氢键的能力。介绍在最近的两个通信（货车Niekerk和Schoening，1952年a，B）的晶体结构的potassium和铵triquatochromate（III）已被描述。在后者中，讨论了两种不同的方案，根据这两种方案，络离子和阳离子在两种结构中排列。这种排列上的差异是由于（1）阳离子大小的差异，还是（2）铵离子形成氢键的能力，这个问题仍然没有答案。为了获得关于第一点的进一步信息，决定研究相应的铷和铯化合物的结构。Gold-Schlemen和Pauling给出了这些离子的有效离子半径的以下数据：
By comparing Weissenberg photographs, Harker sections and Patterson projections it is shown that the compound Rb3 [Cr (C~ 04) 3]. xH20 and the corresponding potassium compound are isotype. The corresponding ammonium compound has a different structure. It is shown that this difference in structure is not due to the different sizes of the cations, but that it is probably due to the ability of an ammonium ion to form tetrahedrally directed hydrogen bonds.Introduction In two recent communications (van Niekerk & Schoening, 1952a, b) the crystal structures of po-tassium and ammonium trioxalatochromate (III) have been described. In the latter publication the two different schemes, according to which the complex ions and the cations are arranged in the two struc-tures, were discussed. The question whether this difference in arrangement was due to (1) the difference in size of the cations, or (2) the ability of an ammonium ion to form hydrogen bonds, remained unanswered. To get further information as regards the first point it was decided to investigate the structures of the corresponding rubidium and cesium compounds. Gold-schmidt and Pauling give the following data for the effective ionic radii of these ions: