GROWING CRYSTALS FROM LIQUIDS AND GASES. Alexander J. Blake, Department of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, UK and Norbert W. Mitzel, Simon Parsons and David W.H. Rankin, Department of Chemistry, The University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK

A survey of the structural databases reveals a basic discontinuity in known crystal structures: those with melting points below ambient temperatures, which are often compounds of great interest, are very poorly represented. The reason for this is obvious and practical-obtaining single crystals of compounds which are liquid or gaseous at room temperature can be orders of magnitude more difficult and labour-intensive than for compounds which are crystalline solids under the same conditions.

Despite these problems, we have succeeded with a wide range of materials, both organic and inorganic, including semiconductor precursors, 1:1 adducts and compounds of fluorine, germanium, indium, phosphorus, sulphur and silicon. Although a few of these compounds could be handled using standard techniques oil-drop techniques (Kottke & Stalke, 1993) or adaptations of these, the low melting points and reactivity of most of them demand in situ growth from samples pre-sealed into Pyrex capillary tubes.

Recent results on some silicon and germanium compounds will be reported.

Reference: Kottke, T. & Stalke, D.(1993). J. Appl. Cryst. 26, 615-619.