Abstract

<h2>Acta Crystallographica</h2><h3></h3><h3>0365-110X</h3> <h2>research papers</h2> Volume 23 Part 1 Pages 35-38 July 1967 <h2>The determination of accurate unit-cell dimensions from inclined Weissenberg photographs</h2> N. W. Alcock and G. M. Sheldrick Acta Cryst. (1967). 23, 35 The Determination of Accurate Unit-cell Dimensions from Inclined Weissenberg Photographs BY N. W. ALCOCK* AND G. M. SHELDRICK University Chemical Laboratory, Cambridge, England (Received 26 October 1966) The method of Main and Woolfson for obtaining accurate unit-cell dimensions from ordinary zero-layer Weissenberg photographs is extended to general (including equi-inclination) upper-layer Weissenberg and oscillation photographs. Introduction Main & Woolfson (1963) showed that accurate unit- cell dimensions could be obtained from the separations of the cq -(x2 doublets on ordinary zero-layer Weissen- berg photographs. The results are insensitive to errors in the camera radius and the same photographs are used for the intensity measurements and the deter- mination of unit-cell dimensions; thus the method is particularly appropriate to low temperature studies. However when a crystal is grown in situ it is sometimes possible to obtain good photographs only about a single oscillation axis, with the result that not all the unit-cell dimensions can be determined from the single zero-layer photograph. Hence we have extended the technique