Na 3 F[WO 4 ]: A Sodium Fluoride Ortho ‐Oxotungstate(VI) with Strands of Face‐Shared Fluoride‐Centred Sodium Octahedra According to $^{1}_{\infty}\rm \{[FNa_{6/2}]^{2+}\}$

During the reaction of Na 2 [WO 4 ] with YF 3 purposed to yield fluoride‐derivatized yttrium oxotungstates(VI), colourless platelet‐shaped single crystals of Na 3 F[WO 4 ] emerged as main product. The title compound crystallizes orthorhombically in the space group Pnma (a = 559.59(5), b = 751.02(7), c = 1285.98(9) pm) with four formula units per unit cell. Besides isolated ortho ‐oxotungstate units [WO 4 ] 2− (d(W–O) = 176–178 pm) the crystal structure contains two crystallographically independent Na + cations which are both octahedrally coordinated by four oxygen atoms and two fluoride anions. The F − anions are surrounded by six sodium cations (d(F–Na) = 224–242 pm) also in an octahedral fashion. These octahedra built up chains along [100] by sharing trans ‐oriented faces according to $^{1}_{\infty}\rm \{[FNa_{6/2}]^{2+}\}$ , which are stacked according to a hexagonal closest rod‐packing. The cationic strands are surrounded, interconnected and charge‐balanced by isolated [WO 4 ] 2− tetrahedra with almost ideal shape and every O 2− ligand is terminally coordinated by three Na + cations.