Crystal structure and chemical constitution of basic beryllium acetate and propionate

Abstract

The co-ordination theory of molecular structure postulates the existence for each valent chemical element of an integer representing the maximum number of associating units which can be grouped around the atomic sphere of the element. This so-called “ co-ordination number ” varies with the atomic volume of the element, and although in the case of elements of medium atomic volume the number is generally six, yet with elements of small atomic volume this number is diminished to four or even less. This conception of co-ordination was elaborated by Alfred Werner into a comprehensive theory of chemical combination and molecular structure long before the electronic constitution of chemical atoms had been revealed, but nevertheless the co-ordination theory has been shown to accord with many of the new facts since discovered by infra-atomic investigations and by X-ray analysis.