Synthesis and crystal structure of a novel pentaborate, Na3ZnB5O10

A novel ternary borate, trisodium zinc pentaborate, Na3ZnB5O10(), has been prepared by solid-state reaction at temperature below 750 degrees C. The single-crystal X-ray structural analysis showed that Na3ZnB5O10 crystallizes in the monoclinic space group P2(1)/n with a = 6.6725(7)angstrom, b = 18.1730(10)angstrom, c = 7.8656(9)angstrom, beta = 114.604(6)degrees, Z = 4. It represents a new structure type in which double ring [B5O10](5-) building units are bridged by ZnO4 tetrahedra through common O atoms to form a two-dimensional (2)(infinity)[ZnB5O10](3-) layer that affords one-dimensionai channels running parallel to the [101] direction. Symmetry-cen ter related (2)(infinity)[ZnB5O10](3-) layers are stacked along the b-axis, with the interlayer void spaces and intralayer open channels filled by Na+ cations to balance charge. The IR spectrum further confirms the presence of both BO3 and BO4 groups and UV-vis diffuse reflectance spectrum shows a band gap of about 3.2eV. (c) 2007 Elsevier Inc. All rights reserved.