Synthesis, Structure, and Catalytic Properties of Rare-Earth Ternary Sulfates

Three rare-earth ternary sulfates NaM(SO 4 ) 2 ·H 2 O (M = La, Nd, and Gd) have been hydrothermally synthesized, and the crystal structures of the three compounds have been solved by single-crystal X-ray diffraction. The lanthanum and neodymium sulfates show the space group P 3 1 21 while the gadolinium compound presents the enantiomer P 3 2 21. The three lanthanum, neodymium, and gadolinium sulfates have been tested as heterogeneous redox catalysts in the selective oxidation of sulfides, showing good activities and selectivities. They can be reused without loss of yield or selectivity.