Lanthanum(III) sulfide is a binary inorganic chemical compound of lanthanum metal and sulfur with the chemical formula . At least three polymorphs are known, referred to as α, β, and γ.
Synthesis Lanthanum(III) sulfide can directly be produced by treating metallic lanthanum with sulfur:
Once prepared, lanthanum(III) sulfide can be purified by chemical vapor transport using iodine.
Lanthanum(III) sulfide can also be prepared by treating the sulfate with hydrogen sulfide at elevated temperatures:
Physical properties Dilanthanum trisulfide forms reddish-yellow crystals of the cubic system, with space group I43d, and unit cell parameters a = 0.8706 nm. The α polymorph features two types of La3+ centers, one with Capped trigonal prismatic molecular geometry and one is bicapped trigonal prismatic molecular geometry.
It does not dissolve in cold water.
Chemical properties Reacts with hot water:
Reacts with acids:
Oxidized by oxygen in atmosphere:
Uses is used as a precursor to prepare complex compounds. It is also used in glass manufacturing and in optical fibers.
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