NH4Ag3(PO3F)2, a layered monofluorophosphate(V) with seven different Ag sites

Single crystals of ammonium trisilver bis[fluorophosphate(V)], NH4Ag3(PO3F)(2), were obtained from an aqueous solution and the structure was refined from a racemically twinned crystal. The asymmetric unit contains seven crystallographically distinct Ag atoms (two of which are located on twofold axes), four PO3F tetrahedra and two ammonium cations. The layered structure is composed of silver-monofluorophosphate sheets, [Ag-3(PO3F)(2)](-), that extend parallel to (100). The F atoms of the PO3F tetrahedra point towards the ammonium cations, which are located in the interlayer space and stabilize the structure via moderate N-H...O and N-H...F hydrogen bonds.