Synthesis of MixedAnion Rare Earth Sulfate Fluorides <i>Ln</i>SO₄F·H₂O (<i>Ln</i> = Nd, Tb, Dy, and Ho)and <i>Ln</i>SO₄F (<i>Ln</i> = Tb,Dy, and Ho)

Single crystals of the mixed anion rare earth sulfate fluorides <i>Ln</i>SO₄F·H₂O (<i>Ln</i> = Nd, Tb, Dy, and Ho), monoclinic space group <i>P</i>2₁/<i>n</i>, were prepared via an HF-free mild hydrothermal synthesis. Furthermore, the <i>Ln</i>SO₄F (<i>Ln</i> = Tb, Dy, and Ho) phases, orthorhombic space group <i>Pnma</i>, were obtained via the thermal decomposition of <i>Ln</i>SO₄F·H₂O (<i>Ln</i> = Tb, Dy, and Ho). While the <i>Ln</i>SO₄F·H₂O (<i>Ln</i> = Nd, Tb, Dy, and Ho) phases are isostructural, two different structures are observed for the <i>Ln</i>SO₄F (<i>Ln</i> = Tb, Dy, and Ho) series, one for Tb and one for Dy and Ho, differing in the rare earth coordination environments. Green photoluminescence is observed for Tb(SO₄)F·H₂O and Tb(SO₄)F. Magnetic measurements indicate the absence of magnetic order down to 2 K in the <i>Ln</i>(SO₄)F·H₂O and <i>Ln</i>(SO₄)F phases.