Good work Armel. I knew that crack about X-rays would get you going :-)
But was it ICSD or the original authors who reported half a sulpher atom
and OH instead of H2O ?
This is a good example of the possible pitfalls in searching databases. If you
search for the formula given by Kristian, you get no result. If you broaden
the search to "Ca Al O H S" you get 33 results (too many for lazy people like me).
If you assume the X-ray people at least got the formula for the heavy atoms
right :-) and search for "Ca4 Al2 S1 O H" (as I did) you get only the structure
I quoted (which is probably related). If you search for "Ca Al O H S" with only 5
types of atoms (which maybe Armel did) you get only 5 answers, of which the
half formula result (but you perhaps miss related structures).
The lessons are that you should try all these searches, not just one, and that
the X-ray people don't even get the heavy atom formula right :-)
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/