Na3Cd3B(PO4)4: a new noncentrosymmetric borophosphate with zero-dimensional anion units.

A new noncentrosymmetric borophosphate, Na(3)Cd(3)B(PO(4))(4), has been successfully synthesized by conventional solid state reaction for the first time. It crystallizes in the orthorhombic space group Pmc2(1) with unit cell parameters of a = 13.6854(3) Å, b = 5.3346(11) Å, c = 18.2169(4) Å, and Z = 4. Na(3)Cd(3)B(PO(4))(4) features zero-dimensional [B(PO(4))(4)](9-) anion units with Cd(2+) and Na(+)/Cd(2+) cations located around them, in which the BO(4) tetrahedron is surrounded by four PO(4) tetrahedra by sharing the vertexes of O atoms. Second harmonic generation (SHG) measurements show that Na(3)Cd(3)B(PO(4))(4) exhibits a SHG response 1.1 times larger than that of KH(2)PO(4) (KDP) and is phase matchable.