(NH4)3(H3O)Zn4(PO4)4: A nonlinear optical zinc orthophosphate crystal

Phosphate crystals are valuable materials according to their diverse structures and physical and chemistry properties. A zinc orthophosphate, (NH 4 ) 3 (H 3 O)Zn 4 (PO 4 ) 4 , has been obtained via hydrothermal route. It was crystallized in hexagonal space group P 6 3 , featuring a three-dimensional (3D) [Zn(PO 4 )] – anion network built by corner-sharing connected ZnO 4 and PO 4 tetrahedra. The NH 4 + and H 3 O + units are located in the six-member cavities of the framework as the balanced cations. (NH 4 ) 3 (H 3 O)Zn 4 (PO 4 ) 4 exhibits a moderate and phase matchable second harmonic generation effect (SHG) about 1.4 times of KH 2 PO 4 (KDP), which is the strongest in zinc orthophosphates. Besides structural features, optical properties measurements and theoretical analyses of (NH 4 ) 3 (H 3 O)Zn 4 (PO 4 ) 4 were performed.