Dear David, I have scanned the email and have no comments to make. Thank you, Owen Johnson. -- Technical Support Group - the Cambridge Crystallographic Data Centre 12 Union Road, CAMBRIDGE. CB2 1EZ UK Web: http://www.ccdc.cam.ac.uk Tel:(44) 01223 336023 Fax:(44) 01223 336033 Enq:(44) 01223 336408