Trimeric anions in KTeO2F

KTeO2F was prepared by solid state reaction from KF and TeO2 at 350 degrees C. The structure has been determined by single crystal X-ray analysisp [P2 (1)/n, Z = 12, a = 1177.8(2) pm, b = 1499.0(3) pm, c = 619.5(2) pm, beta = 94.11(2) degrees, R-1 = 0.0266, wR(2) = 0.0604]. A characteristic feature o f the structure is the presence of trimeric anions Te3O6F33- in which the t ellurium atoms are bridged by oxygen atoms. The lone pairs are stereoactive leading to pseudotrigonal bipyramidal coordination at the tellurium atoms. Additional weak bonding interactions Link these trimeric anions resulting in a layered structure.