Cerium(III) sulfate
Cerium sulfate, also called cerous sulfate, is an inorganic compound with the formula Ce23. It is one of the few salts whose solubility in water decreases with rising temperature.
Cerium sulfate is a hygroscopic white solid, which begins to decompose above 600°C. It has a monoclinic crystal structure.
Cerium sulfate tetrahydrate is a white solid that releases its water of crystallisation at 220 °C. It has a monoclinic crystal structure with the space group P21/c. The nonahydrate has a hexagonal crystal structure with the space group P63/m. Hydrates of this compound are known with 12, 9, 8, 5, 4 and 2 parts of water of crystallisation.