Neodymium(III) sulfide
Neodymium sulfide is an inorganic chemical compound with the formula Nd2S3 composed of a two neodymium atoms in the +3 oxidation state and three sulfur atoms in the −2 oxidation state. Like other rare earth sulfides, neodymium sulfide is used as a high-performance inorganic pigment.
Preparation
Neodymium sulfide can directly be produced by reacting neodymium with sulfur:Once prepared, neodymium sulfide can be purified by chemical vapor transport using iodine.
It can also be produced by treating neodymium oxide with hydrogen sulfide at 1450 °C:
Properties
Neodymium sulfide is a light green solid. The compound comes in three forms. The α-form has an orthorhombic crystal structure, the β form has a tetragonal crystal structure, and the γ form has a cubic crystal structure. At 1650 °C in a vacuum, the γ compound decomposes to form neodymium monosulfide.Neodymium 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 Nd2S3 and Nd3S4. Neodymium sulfide is an electrical insulator.