The present volume continues the aim of Structure Reports to present critical accounts of all crystallographic structure determinations. 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. 41B or 42A, pages vi-viii). University of British Columbia 1. TROTIER Vancouver, Canada 15 July 1978 VI] STRUCTURE REPORTS SECTION I...