FEALF5 - SYNTHESIS END CRYSTAL-STRUCTURE

FeAlF5 appears in the thermolysis products of (TMA)MIIIF4 · H2O-(TMA) = [(CH3)4N], MIII = (Fe0.5Al0.5)-and of FeAlF5 · 7H20. Its structure is solved ab initio from the X-ray powder diffraction pattern (S.G. Immm, a = 7.4289(8) Å, b = 6.203(1) Å, and c = 3.5574(6) Å, Z = 2, RB = 0.10). The network is constituted by two kinds of chains running along the c axis: AlF6 octahedra form trans-chains whereas FeF6 octahedra build edge sharing rutile-like chains. FeAlF5 can be considered as the aristo-type structure from which derive some ABF5 networks. The Mössbauer study characterizes two Fe2+ contributions involving respectively a small cationic inversion and a classical paramagnetic behavior down to 4.2 K due to the rutile type arrangement of the FeIIF6 octahedra. © 1994 Academic Press, Inc.