This volume is the seventh classified bibliography of organic and organometallic crystal structures prepared by the Crystallographic Data Centre, University Chemical Laboratory, Cambridge, and published jointly with the International Union of Crystallography. The first six volumes covered the years 1935-1974. The present volume provides references principally to compounds whose struc­ tures were reported in the literature during 1974-1975. A few structures published prior to 1974 and omitted from the previous volumes are also included. There are three cumulative indexes in the present volume: formula, transition metal and author indexes. All three cover the period 1935- 1975 and give references to entries in Vols. 1-7. The bibliography