Preparation and properties of some amorphous chromium(III) phosphates
Abstract
Amorphous chromium(III) phosphates of the composition CrPO 4· xH 2O (x = 3.8, 4.1, 4.4 and 6.7) have been prepared by reducing CrO 3 with ethanol in the presence of orthophosphoric acid at temperatures ranging from -24°C to +80°C. Infrared spectra of the products are typical of metal orthophosphates, whereas TG analysis shows that they contain both water of hydration and water of coordination. Electronic spectroscopy reveals that the Cr 3+ ions are coordinated by water molecules as well as by PO 4 3- ions, the spectral bands being somewhat broadened due to the amorphous nature of the materials. The products prepared above 0°C apparently exhibit small distortions from octahedral symmetry at Cr 3+ sites.
- Publication:
-
Journal of Non Crystalline Solids
- Pub Date:
- May 1989
- DOI:
- 10.1016/0022-3093(89)90451-1
- Bibcode:
- 1989JNCS..109..129V