Bi(IO )F : The First Metal Iodate Fluoride with a Very Strong Second Harmonic Generation Effect.

The first metal iodate fluoride, Bi(IO )F , with a strong second harmonic generation (SHG) effect has been prepared. Bi(IO )F crystallizes in the polar space group C2 and features a three-dimensional [BiF ] cationic framework with IO groups capping the inner walls of the one-dimensional tunnels. This [BiF ] cationic framework acts as a template for the assembly of the polar IO units in a favorable superposed fashion, which leads to the polar structure of the material. Bi(IO )F displays a rather wide transmittance window (0.3-11 μm) and exhibits a very strong SHG response that is about 11.5 times larger than that of KH PO (KDP) under 1064 nm laser radiation and the same as that of KTiOPO (KTP) under 2.05 μm laser radiation. Preliminary investigations indicate that Bi(IO )F is a promising nonlinear optical material in the visible and mid-IR region.