Neodymium(III) sulfide

Neodymium(III) sulfide is a 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(III) sulfide is used as a high-performance inorganic pigment.

Preparation
Neodymium(III) sulfide can directly be produced by reacting neodymium with sulfur:
 * 2Nd + 3S → Nd2S3

It can also be produced by sulfidizing neodymium oxide with H2S at 1450 °C:
 * Nd2O3 + 3 H2S → Nd2S3 + 3 H2O

Properties
Neodymium(III) sulfide is (as γ-form) 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(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 Nd2S3 and Nd3S4. Neodymium(III) sulfide is an electrical insulator.