New mixed aluminium-chromium diarsenate.
Potassium chromium aluminium diarsenate, KCr1/4Al3/4As2O7, was prepared by solid-state reaction. The structure consists of (Cr1/4/Al3/4)O6octa-hedra and As2O7diarsenate groups sharing corners to build up a three-dimensional anionic framework. The potassium cations are located in wide channels running along thec-axis direction. The crystal structure is isostructural with the triclinicAIMIIIX2O7(AI= alkali metal;MIII= Al, Cr, Fe;X= As, P) compounds. However, theMIIIocta-hedrally coordinated site is 25% partially occupied by chromium and 75% by aluminium.
Laboratoire de Materiaux et Cristallochimie, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Manar II Tunis, Tunisia.
Mohamad Alem
MA
Bouhassine
Laboratoire de Materiaux et Cristallochimie, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Manar II Tunis, Tunisia.
Habib
H
Boughzala
channel structure; crystal structure; diarsenate; mixed occupancy; single crystal diffraction