title: Ba4Ga2B8O18Cl2.NaCl: a new polar structure with NaCl inclusion.
abstract: The title compound, Ba4Ga2B8O18Cl2.NaCl, is found to crystallize in a polar space group P4(2)nm with cell dimensions of a = 12.1134(2) A and c = 6.8456(1) A. The basic building blocks of the structure are the B4O9 groups, which are interconnected by the GaO4 tetrahedron to form a three-dimensional net with Ba2+ ion-, Cl- ion-, and NaCl molecule-filled tunnels. This net structure is closely related to that of mineral hilgardite, with which many variant compounds have been found. Both a powder second-harmonic-generation test and calculations suggest that it possesses an optical nonlinearity comparable to that of potassium dihydrogen phosphate.
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China. rkli@cl.cryo.ac.cn
authors.forename: R K
authors.initials: RK
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Yu