Title: Gallium
CAS Registry Number: 7440-55-3
Literature References: Ga; at. wt 69.723; at. no. 31; valences 3, 2, 1. Group IIIA (13). Natural isotopes: 69 (60.2%); 71 (39.8%); artificial radioactive isotopes: 63-68; 70; 72-76. Best source is the mineral germanite, a copper sulfide ore; occurs in very small quantities in zinc blendes, in aluminum clays, found in ores of iron, chromium, manganese; constitutes 5 ´ 10-4% of the crust of the earth. Discovered by L. Boisbaudran, Compt. Rend. 81, 493, 1100 (1875); 82, 163, 1036 (1876); isolated pure by L. Boisbaudran and E. Jungfleisch, Bull. Soc. Chim. [2] 31, 50 (1879). Isoln from rhenium-rich copper schist: Feit, Angew. Chem. 46, 216 (1933). From bauxite: Chem. Eng. News 34, 4300 (1956). Purification by zone melting: Chem. Ztg. 80, 787 (1956). Alternate methods of purification: Gebauhr, US 2928731; Merkel, US 2927853 (both 1960 to Siemens-Schuckert). Spectra: L. Boisbaudran et al., cited in Mellor's vol. 5, 378 (1929). Reviews: Wagner, Gitzen, J. Chem. Educ. 29, 162 (1952); Greenwood, Inorg. Chem. Radiochem. 5, 91-134 (1963); Wade, Banister, Comprehensive Inorganic Chemistry vol. 1, J. C. Bailar, Jr. et al., Eds. (Pergamon Press, Oxford, 1973) pp 997-1000, 1069-1117; P. de la Bretèque in Kirk-Othmer Encyclopedia of Chemical Technology vol. 11 (Wiley-Interscience, New York, 3rd ed., 1980) pp 604-620. Review of antineoplastic properties and clinical applications of gallium salts: P. Collery et al., Crit. Rev. Oncol. Hematol. 42, 283-296 (2002).
Properties: Grayish metal; possesses a greenish-blue reflection; tin- or silver-like when molten; has a crystalline orthorhombic texture. mp 29.78°. bp approx 2400°: Cochran, Foster, J. Electrochem. Soc. 109, 144 (1962). Shows a tendency to remain in supercooled state. Contracts on melting; d29.65 (solid) 5.9037; d29.8 (liq) 6.0947: Richards, Boyer, J. Am. Chem. Soc. 43, 274 (1921). Heat capacity: 0.09 cal/g/°C (0-24°, solid). Latent heat of fusion 19.16 cal/g. Stable in dry air; tarnishes in moist air or oxygen. Reacts with alkalies with evolution of hydrogen; attacked by cold concd hydrochloric acid; rendered passive by hot nitric acid; readily attacked by halogens.
Melting point: mp 29.78°
Boiling point: bp approx 2400°: Cochran, Foster, J. Electrochem. Soc. 109, 144 (1962)
Density: d29.65 (solid) 5.9037; d29.8 (liq) 6.0947: Richards, Boyer, J. Am. Chem. Soc. 43, 274 (1921)
Derivative Type: Suboxide
CAS Registry Number: 12024-20-3
Molecular Formula: Ga2O
Molecular Weight: 155.45
Percent Composition: Ga 89.70%, O 10.29%
Properties: Brown powder; obtained by heating the sesquioxide and the metal at 700°; stable in dry air; dec above 800°; converted to the trivalent state by nitric acid or bromine.
Derivative Type: Hydroxide
CAS Registry Number: 12023-99-3
Molecular Formula: Ga(OH)3
Molecular Weight: 120.75
Percent Composition: Ga 57.74%, O 39.75%, H 2.50%
Properties: A gelatinous precipitate; obtained by the action of ammonia or alkali hydroxide on a soln of a gallic salt.
CAUTION: Administration to humans has caused metallic taste, skin rashes, bone marrow depression: H. E. Stokinger in Patty's Industrial Hygiene and Toxicology vol. 2A, G. D. Clayton, F. E. Clayton, Eds. (Wiley-Interscience, New York, 3rd ed., 1981) pp 1630-1637. |