Amorphous aluminosilicates containing trivalent chromium in a non-octahedral coordination environment

摘要

Amorphous aluminosilicates containing up to 5.8 wt. chromium have been prepared by cation exchange on an amorphous sodium aluminosilicate using Cr(III) salts. Electronic spectroscopy has shown that the ligand arrangement around the Cr(III) sites does not correspond to the octahedral geometry. No isomorphous substitution of Al3+by Cr3+in the aluminosilicate occurs, and it is not possible to exchange back chromium by Na+ions. The amorphous chromium-substituted aluminosilicates (abbr. ACSAS) are slightly acidic and when heated in air at 800 °C no oxidation of Cr(III) takes place. The chromium species in the ACSAS undergoes ligand replacement reactions