M4O(IO3)(3)(I3O7F3)BF4 (M = Pb, Sr): Promising Nonlinear Optical Materials Featuring the Unprecedented Windmill-Shaped [I3O7F3](2-)Polyfluoroiodate Anion

The first examples of metal trifluoroiodates, namely, M4O(IO3)(3)(I3O7F3)BF4 (M = Pb, Sr), have been synthesized. Both compounds feature an interesting windmill-shaped [I3O7F3](2-)trimer polyfluoroiodate anion. Optical performance measurements revealed that M4O(IO3)(3)(I3O7F3)BF4 (M = Pb, Sr) exhibits excellent comprehensive performance, which indicates that it is a promising optical crystal in the near-ultraviolet and mid-infrared regions.