CRYSTAL-STRUCTURE OF THALLIUM TRIBORATE, TLB3O5

Thallium triborate, TlB3O5 (TBO), crystallizes in the orthorhombic sys tem, space group P2(1)2(1)2(1) with unit cell dimensions a = 5.2099(3) Angstrom, b = 8.248(1) Angstrom, and c = 10.206(2) Angstrom; Z = 4. T he structure was solved from 1340 independent reflections to R = 0.038 and R-w = 0.041. The berate anion of the structure forms a three-dime nsional framework built up from B3O3 rings; its shorthand notation is 3:infinity(3)(2 Delta+T), where Delta is a BO3 triangle and T is a BO4 tetrahedron, This compound is isostructural with CsB3O5 (CBO) but som e differences exist in the oxygenated surroundings of cesium and thall ium cations due to the larger size of Cs+, Like CBO, TBO may be a good candidate for nonlinear optical applications as a second harmonic gen erator. (C) 1997 Academic Press.