The present volume continues the aim of Structure Reports to present critical accounts of all crystallographic structure determip. ations. The increase in the number of crystal structure papers (now about 2000 per year in the Organic Section) has prompted a minor change in format, which increases the information density per page, hopefully without any loss of clarity. Details of the arrangement in the volumes, symbols used etc. are given in previous volumes (e. g. 41 B or 42A, pages vi-viii). J. TROTTER University of British Columbia Vancouver, Canada 14 September 1978 [VI] STRUCTURE REPORTS SECTION III ORGANIC COMPOUNDS Edited by G. Ferguson with the assistance of M. Currie D. F. Rendle J. Iball S. J. Rettig A. L. Macdonald S. N. Scrimgeour W. C. Marsh J. C. Speakman M. Napier ARRANGEMENT To find a particular organic compound the subject index or the formula index should be used. The general arrangement is: aliphatic or open-chain compounds; open chains with N, S; benzene derivatives; cyclic hydrocarbons; condensed ring systems; heterocyclic compounds; carbohydrates, amino-acids, natural products; molecular complexes; organometallic compounds - B, Si, P, As, Sb, groups lA, IIA, III, IV, VI; transition metal complexes - w-complexes, other ligands. Only com plete structure analyses are described; compounds for which only lattice para meters are determined, and those which have been described only in preliminary communications and for which details will appear at a later date, have not been reported.