The Effect of Sucrose on the Activities of Certain Ions

Abstract

This determination of the arsenic to oxygen distance is, so far as the writer is aware, the only basis for an experimental value of the arsenic radius. Taking the oxygen radius as 0.65 Á., the arsenic radius is 1.36 Á. The radius of antimony is found in the same way to be 1.57 A.The arrangement of the atoms within the molecule is the same as that of the carbon and nitrogen atoms in hexamethylenetetramine, CeN^H^, as determined by Dickinson and Raymond.7 The considerations concerning the tetrahedral angles that hold for the latter compound apply also to arsenious and antimonous oxides. SummaryThe crystal structures of arsenious and antimonous oxides have been determined by means of Taue photographs and spectral photographs. These crystals may be regarded as composed of As4Oe and Sb4Oe molecules having a diamond arrangement, each molecule corresponding to 1 carbon atom. See Fig. 1. The arrangements are derived from the space group Ol The sizes of the unit cubes containing 8 molecules of As406 or Sb406 are 11.06 Á. for arsenious oxide and 11.14 Á. for antimonous oxide. The shortest distance between arsenic and oxygen atoms is 2.01 A., and between antimony and oxygen atoms is 2.22 A.