© 1998 by Udo J.A. Behner
© 1998 by Udo J.A. Behner
| chemical formula | : NH4H2PO4 |
| crystal class | : tetragonal skalenoedric |
| growing method | : slowly cooling of the aquaeous solution |
| growing time | : app. 7 days |
| crystal size | : up to 10 centimeters |
Ammonium dihydrogenphosphate for which the shortcut
"ADP" is used, was and also is grown in large single
crystals on a commercial scale. They are used in piezoelectric
devices, as frequency doublers in laser optics and for there
ferroelectric and optoelectric properties.
Since this material is cheap and not toxic its also widely used
for hobby crystal growth. Its not as easy to grow as alum but the
results are worth some efforts.
Very strange is the capability of ADP to include large amounts of
chromium(III) into its crystals lattice, which results in a green
coloring (in spite the fact that chromium(III)salts in aquous
solution are red to purple !).
The chromium content of the solution is also helpfull to grow
better developed crystal tips.
This specimen is currently exhibited at the mineral museum in
Pforzheim