Title: Indium
CAS Registry Number: 7440-74-6
Literature References: In; at. wt 114.818; at. no. 49; valence 3, 2, 1. Group IIIA(13). Natural isotopes: 115 (95.77%); 113 (4.23%); 115In is a b- emitter, T? 6 ′ 1014 years. Artificial radioactive isotopes: 107-112; 114; 116-124. Occurrence in the earth's crust: 1 ′ 10-5%. Discovered in sphalerite ore by Reich and Richter in 1863. Generally found in zinc blendes. Monograph: M. T. Ludwick,
Indium (Indium Corp. of America, Utica, N.Y., 1950).
Review: Wade, Banister in
Comprehensive Inorganic Chemistry vol. 1, J. C. Bailar, Jr.
et al., Eds. (Pergamon Press, Oxford, 1973) pp 997-1000, 1065-1117; E. F. Milner, C. E. T. White in
Kirk-Othmer Encyclopedia of Chemical Technology vol. 13 (Wiley-Interscience, New York, 3rd ed., 1981) pp 207-212.
Properties: Soft, white metal with bluish tinge. Emits a "tin cry" on bending. Ductile, malleable, softer than lead, leaves a mark on paper. Quite stable in air. Crystallizes and is diamagnetic. d20 7.3. mp 155°. bp 2000°. Sp heat: 0.0568 cal/g/°C. Hardness (Mohs') = 1.2. Unaffected by water; attacked by mineral acids. Very resistant to alkalies.
Melting point: mp 155°
Boiling point: bp 2000°
Density: d20 7.3
CAUTION: Indium salts are relatively nontoxic when administered orally; highly toxic when administered subcutaneously or intravenously. Experimental animal poisoning has produced injury to blood, heart, liver, kidneys: E. Browning,
Toxicity of Industrial Metals (Appleton-Century-Crofts, New York, 2nd ed., 1969) pp 164-168.
Use: In bearing alloys; as a thin film on moving surfaces made from other metals. In dental alloys. In semiconductor research. In nuclear reactor control rods (in the form of an Ag-In-Cd alloy).
