NaAl(SO₄)F₂: a single-layer two-dimensional perovskite

The crystal structure of the sodium aluminium difluorosulfate NaAl(SO₄)F₂ has been determined from laboratory powder diffraction data. Its characterization allows for improving the monitoring of aluminium industrial production starting from cryolite. It is characterized by a perovskite single layer formed by the fluorine corner-sharing of [AlF₄O₂] octahedra with SO₄ groups, and sodium as the interlayer content. This could be the n = 1 member of a possible new family of 2D perovskite materials AM_n(SO₄)F_3n–1 (A⁺ = Na, Li; M³⁺ = Al, Fe, V, Cr), which remains to be confirmed.