Neodymium(III) sulfide is an inorganic chemical compound with the formula Nd<sub>2</sub>S<sub>3</sub> composed of a two neodymium atoms in the +3 oxidation state and three sulfur atoms in the âÂÂ2 oxidation state. Like other rare earth sulfides, neodymium(III) sulfide is used as a high-performance inorganic pigment.
Neodymium(III) sulfide can directly be produced by reacting neodymium with sulfur:
Once prepared, neodymium(III) sulfide can be purified by chemical vapor transport using iodine.
It can also be produced by treating neodymium oxide with hydrogen sulfide at 1450 ðC:
Neodymium(III) sulfide is (as ó-form) a light green solid. The compound comes in three forms. The ñ-form has an orthorhombic crystal structure, the ò form has a tetragonal crystal structure, and the ó form has a cubic crystal structure. At 1650 ðC in a vacuum, the ó compound decomposes to form neodymium monosulfide.
Neodymium(III) sulfide has a high melting point and a lot of polymorphic forms which make it difficult to grow. When heated, neodymium sulfide can lose sulfur atoms and can form a range of compositions between Nd<sub>2</sub>S<sub>3</sub> and Nd<sub>3</sub>S<sub>4</sub>. Neodymium(III) sulfide is an electrical insulator.