Abstract
The new non-centrosymmetric tin fluoride borate Sn(3) [B(3) O(7) ]F was synthesized hydrothermally, and was characterized by single-crystal and powder X-ray diffraction, vibrational spectroscopy, DFT calculations, second harmonic generation (SHG) measurements, thermogravimetry, and differential scanning calorimetry. Its SHG response is about 12 times that of quartz. The compound crystallizes in the non-centrosymmetric orthorhombic space group Pna2(1) with lattice parameters a=922.4(2), b=769.8(4), and c=1221.9(6) pm (Z=4). Characteristic for the structure are isolated B(3) O(7) moieties, consisting of two corner-sharing BO(3) units and one BO(4) tetrahedron. These occupy half of the octahedral voids of a slightly distorted hexagonal closest packing of Sn(2+) atoms, with [SnF](+) units in the other half of the octahedral voids. Sn(3) [B(3) O(7) ]F is transparent over a wide spectral range with a UV cut-off edge at about 263 nm.