Abstract
Traditional fluorides are rarely reported as candidates for nonlinear optical (NLO) materials featuring a deep-ultraviolet cutoff edge. Theoretical investigations suggest that the ZrF(8) dodecahedron shows large polarizability anisotropy and benefits for large birefringence. Herein, a new fluorine-rich fluoride, K(3)Ba(2)Zr(6)F(31), was synthesized by coupling the ZrF(8) group, featuring acentric cis-[Zr(6)F(34)](10-) clusters with a 6(3)-screw axis. Significantly, K(3)Ba(2)Zr(6)F(31) exhibits a short UV cutoff edge (below 200 nm) and moderate second-harmonic generation (SHG) response (0.5 × KH(2)PO(4)). It also possesses a relatively large birefringence (0.08@1064 nm), together with a broad transparency window (2.5-21.1 μm). First-principles calculations suggest that the cis-[Zr(6)F(34)](10-) cluster built by ZrF(8) dodecahedra are the dominant contributors to the large band gap (7.89 eV, cal.) and SHG response simultaneously. Such systematic work highlights that Zr-based fluorides afford a new paradigm for the development of efficient NLO materials with a short UV cutoff edge.