Zn 3 Sb 4 O 6 F 6 : Hydrothermal synthesis, crystal structure and nonlinear optical properties

Zn 3 Sb 4 O 6 F 6 has been synthesized hydrothermally at 230 °C. The crystal structure was determined from single crystal X-ray diffraction data. It crystallizes in the cubic non-centrosymmetric space group I -43 m with the unit cell parameter a = 8.1291(4) A and is isostructural with M 3 Sb 4 O 6 F 6 (M = Co, Ni). The new compound is the first oxofluoride containing Zn 2+ and a p-element cation with a stereochemically active lone pair. The crystal structure is made up by [ZnO 2 F 4 ] octahedra forming a network via corner sharing at F-atoms and [SbO 3 ] trigonal pyramids that form [Sb 4 O 6 ] cages that connect via the O-atoms to the Zn-atoms. Powder second-harmonic generation (SHG) measurements using 1064 nm radiation on Zn 3 Sb 4 O 6 F 6 indicate an SHG intensity of approximately 40 × α-SiO 2 .