Blackburn A C, Gerkin R E
Department of Chemistry, Ohio State University, Columbus 43210.
Acta Crystallogr C. 1993 Aug 15;49 ( Pt 8):1439-42. doi: 10.1107/s0108270193001714.
The structure of the title compound consists of columns of Ca ions surrounded by four columns of perbromate ions and four columns of water molecules alternating in pairs. The CaO8 complex was found to be dimensionally similar to corresponding complexes in other simple tetrahydrated calcium salts. The eight coordinating O atoms form a polyhedron which departs only slightly from a (distorted) square antiprism. Each of the crystallographically inequivalent perbromate ions was found to conform to rigid-body behavior while the CaO8 complex did not. Although the perbromate ions depart moderately from regular tetrahedral geometry, the mean Br--O bond length agrees well with previously determined values. Hydrogen bonds in this structure involve water-oxygen acceptors as well as perbromate-oxygen acceptors.
标题化合物的结构由钙离子柱组成，其周围环绕着四列高溴酸根离子柱和四列水分子柱，二者成对交替排列。发现CaO8络合物在尺寸上与其他简单的四水合钙盐中的相应络合物相似。八个配位氧原子形成一个多面体，该多面体与（扭曲的）方形反棱柱仅有轻微偏差。发现每个晶体学上不等价的高溴酸根离子符合刚体行为，而CaO8络合物则不然。尽管高溴酸根离子与规则的四面体几何形状有一定偏差，但平均Br—O键长与先前测定的值吻合良好。该结构中的氢键涉及水氧受体以及高溴酸根氧受体。
