BaGaF(IO)(PO): the first fluoride-containing iodate-phosphate with a 1D [GaF(IO)(PO)] helix chain.

Herein, the first F-containing iodate-phosphate, namely BaGaF(IO)(PO), was prepared a hydrothermal reaction, in which HPF (70 wt% solution in water) was used as the source of both fluoride and phosphate anions for the first time. BaGaF(IO)(PO) features an unprecedented 1D [GaF(IO)(PO)] helix chain, composed of a 1D Ga(1)(IO)OF chain the bridging of 0D Ga(2)(PO)F. The UV-Vis spectrum shows that BaGaF(IO)(PO) has a wide bandgap with a short-UV absorption edge (4.35 eV; 253 nm). Birefringence measurement under a polarizing microscope shows that BaGaF(IO)(PO) displays a moderate birefringence of 0.072@550 nm, which is consistent with the value (0.070@550 nm) obtained by DFT calculations, indicating that BaGaF(IO)(PO) has potential applications as a short-UV birefringent material. This study highlights the crucial role played by the incorporation of specific functional groups into compounds, shedding light on their contribution to promising inorganic functional materials.