Synthesis of Mixed Anion Rare Earth Sulfate Fluorides LnSO4F·H2O (Ln = Nd, Tb, Dy, and Ho) and LnSO4F (Ln = Tb, Dy, and Ho)

Single crystals of the mixed anion rare earth sulfate fluorides LnSO4F·H2O (Ln = Nd, Tb, Dy, and Ho), monoclinic space group P21/n, were prepared via an HF-free mild hydrothermal synthesis. Furthermore, the LnSO4F (Ln = Tb, Dy, and Ho) phases, orthorhombic space group Pnma, were obtained via the thermal decomposition of LnSO4F·H2O (Ln = Tb, Dy, and Ho). While the LnSO4F·H2O (Ln = Nd, Tb, Dy, and Ho) phases are isostructural, two different structures are observed for the LnSO4F (Ln = 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 Ln(SO4)F·H2O and Ln(SO4)F phases.