Each of the C70*.zmat files contains a Z-matrix obtained as follows: C70cam.zmat from: Dave HallC70am1.zmat from: David Danovich The first is in the Cambridge X-ray Data Base format and the second is in the AM1 (MOPAC) format. Thanks to Dave and David for mailing these data. Ioan Silaghi-Dumitrescu Universidad Nacional Autonoma de Mexico Instituto de Quimica 04510 Mexico D.F. e-mail: ioan@servidor.unam.mx