True, tho' chalkanthite is, at least in my WWW version (but not in the demo
subset on www.ill.fr/dif/icsd :-( so I am emailing the co-ordinates
Chalkanthite was one of the early neutron measurements of George Bacon,
who redid it 15 years later (Z. Krist. 141 (1975) 330-341).
You may also be interested in our neutron Rietveld refinement of Tutton salt :-)
CuSO4. (NH4)2SO4.6H2O (J.Sol.State Chem. B 51 (1984) 364-375).
There are many other iron/copper sulphate hydrate minerals listed in the full
database, with related structures, so ICSD would be a good investment :-)
Alan Hewat, ILL Grenoble, FRANCE fax (33) 4.76.48.39.06 hewat@ill.fr
ftp://ftp.ill.fr/pub/dif http://www.ill.fr/dif/