Rubidium hydrogen glutarate and ammonium hydrogen glutarate: X-ray studies of quasi-isostructural crystals involving very short hydrogen bonds
Rubidium hydrogen glutarate and ammonium hydrogen glutarate: X-ray studies of quasi-isostructural crystals involving very short hydrogen bonds
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戊二酸氢铷和戊二酸氢铵：涉及非常短氢键的准同构晶体的 X 射线研究
DOI：
10.1007/bf01198531
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发表时间：
1971
期刊：
影响因子：
--
通讯作者：
J. Speakman
中科院分区：
文献类型：
--
作者：
A. Macdonald;J. Speakman
戊二酸氢铷和戊二酸氢铵（M+−CO2.C3H6.CO2H）分别以四个分子结晶，形成尺寸几乎相同的正交晶胞：（M = Rb）a = 18·55，B = 7·57，c = 5·29 Ω;（M = NH 4）a= 18·59，B= 7·56，c= 5· 27 Ω。它们具有非常相似的结构，但它们不是类质同象的：空间群Cmma（Rb）和Pmaa（NH 4）。两者都有无限长的戊二酸残基链，通过非常短的对称氢键首尾相连，O····H···O = 2·40（2）（Rb）和O····H···O = 2·460（6）（NH 4）。NH 4盐的差异来自于碳原子和（特别是）氧原子从这个对称平面中的微小运动。这些是由于N-H···O键合造成的：Rb盐中的两个等效阳离子，每个阳离子与八个氧原子接触，在NH 4盐中通过与不同的四个氧连接而变得不同。
Rubidium and ammonium hydrogen glutarates (M+−CO2.C3H6.CO2H) each crystallize with four molecules in orthorhombic unit cells of almost identical dimensions: (M = Rb)a = 18·55,b = 7·57,c = 5·29 Å; (M = NH4)a= 18·59,b= 7·56,c= 5· 27 Å. They have very similar structures, but they are not isomorphous: space groupsCmma (Rb) andPmaa (NH4).The crystal structures have been determined by three-dimensional X-ray analysis and refined with moderate precision. Both have infinite chains of glutarate residues, linked end-to-end by very short, symmetrical hydrogen bonds, with O···H···O = 2·40(2) (Rb) and O···H···O = 2·460(6) Å (NH4).In the Rb salt, the glutarate residue has strict, crystallographicm symmetry. The difference in the NH4 salt arises from small movements of the carbon and (especially) the oxygen atoms out of this symmetry plane. These are due to N-H···O bonding: two equivalent cations in the Rb salt, each making contact with eight oxygen atoms, become differentiated in the NH4 salt by linkage to different sets of four oxygens.