Structure of Barium Tetrafluorborate Ba2（BF4）4

The title compound Ba2 (BF4)4 crystallizes in the monoclinic spacegroup P21/n with crystallographic parameters: a = 8. 339 (3), b = 16. 530 (7), c =10. 212(4) A, V=1348. 7 A3, β= 106. 64(3)°, Z=4, Dc=3. 06 g/cm3, F(000)=1104, μ=5. 98 mm-1, (MoKa) =0. 71069, M= 621. 90. Least-squares refinementaffords the final residuals R=0. 0639 and Rw=0. 0676 for 2841 observed reflections (I>3(I)). The structure consists of columns of BF4 groups, which parallel to the b direction. All columns are linked together through Ba…F bonds, Both the two crystallographically different barium atoms are nine-coordinated by a distorted tri-capped prismof fluorine atoms from the nearest six BF4 tetrahedrons. There are two types of fluorineatoms, one connecting one barium atom and the other connecting two barium atoms.Each BF4 tetrahedron is connected to three barium atoms, so it (tetrahedron) can beviewed as unidentate ligand and bidentate ligand at the same time.