Tetrachlorides, interatomic distances

X-ray diffraction methods have also been used in the study of the structures of liquids. The continual movements which occur in liquids do not affect the determination of the principal interatomic distances. For earlier work on the subject see Randall s book (1934). Among later papers, those of Harvey (1939) on ethanol and Bray and Gingrich (1943) on carbon tetrachloride are typical. 

The general procedure in the analysis of molecular structure is then as follows. We assume a definite molecular model (a tetrahedron for the tetrachlorides, a hexagon or pentagon for cyclic compounds), and thence deduce the ratios of the different interatomic distances and the number of times each of them occurs in the molecule (periods). If, as in the case of tetrachlorides where the scattering power of the central atom may be neglected (e.g. CCI4), only one period exists, the distribution of intensity in the diffraction pattern may be expected to follow that of the simple function sinx/x (fig. 1). The first maximum occurs... 

---