Title: Thulium
CAS Registry Number: 7440-30-4
Literature References: Tm; at. wt 168.93421; at. no. 69; valences 2, 3. A rare earth metal of the yttrium group; member of the lanthanide series. Naturally occurring isotope (mass number): 169; known artificial radioactive isotopes: 147; 148; 150-168; 170-176. Estimated abundance in earth's crust: 0.2-0.5 ppm. Found in small quantities in euxenite, ytterspar, sipylite, gadolinite, and other rare earth minerals. Discovered in crude erbium oxide: Cleve,
Compt. Rend. 89, 478, 521, 708 (1879). Obtained in a state of high purity by fractional crystn of its bromide: James,
J. Am. Chem. Soc. 32, 517 (1910);
33, 1332 (1911). Sepn from other rare earths by ion exchange: Spedding
et al., ibid. 76, 2557 (1954). Toxicity study: Haley,
J. Pharm. Sci. 54, 663 (1965). Review of prepn, properties and compds:
The Rare Earths, F. H. Spedding, A. H. Daane, Eds. (Krieger, Huntington, N.Y., 1971, reprint of 1961 ed.) 641 pp; Hulet, Bode, "Separation Chemistry of the Lanthanides and Transplutonium Actinides" in
MTP Int. Rev. Sci.: Inorg. Chem., Ser. One vol. 7, K. W. Bagnall, Ed. (University Park Press, Baltimore, 1972) pp 1-45; Moeller, "The Lanthanides" in
Comprehensive Inorganic Chemistry vol. 4, J. C. Bailar, Jr.
et al., Eds. (Pergamon Press, Oxford, 1973) pp 1-101; F. H. Spedding in
Kirk-Othmer Encyclopedia of Chemical Technology vol. 19 (John Wiley & Sons, New York, 3rd ed., 1982) pp 833-854;
Chemistry of the Elements, N. N. Greenwood, A. Earnshaw, Eds. (Pergamon Press, New York, 1984) pp 1423-1449. Brief review of properties: G. T. Seaborg,
Radiochim. Acta 61, 115-122 (1993).
Properties: Silvery-white, easily worked metal. Hexagonal close-packed crystals, d 9.3208. mp 1545°. bp 1725°; also reported as bp 1950° (Spedding, 1982). Heat of fusion: 16.84 kJ/mol. Heat of sublimation (25°): 232.2 kJ/mol. Solns of thulium salts show a characteristic absorption spectrum: Exner, Haschek, cited in
Mellor's vol. V, 698 (1929).
Melting point: mp 1545°
Boiling point: bp 1725°; bp 1950° (Spedding, 1982)
Density: d 9.3208
Derivative Type: Oxide
Synonyms: Thulia
Molecular Formula: O3Tm2
Molecular Weight: 385.87
Percent Composition: O 12.44%, Tm 87.56%
Properties: Dense powder of greenish-white color. Prepd by igniting the oxalate; dissolves slowly in strong acids; exhibits a reddish glow on gentle heating.
Derivative Type: Hydroxide
Molecular Formula: Tm(OH)3
Molecular Weight: 219.96
Percent Composition: Tm 76.80%, O 21.82%, H 1.37%
Properties: White precipitate.
Derivative Type: Chloride heptahydrate
Molecular Formula: TmCl3.7H2O
Molecular Weight: 401.40
Percent Composition: Tm 42.09%, Cl 26.50%, H 3.52%, O 27.90%
Properties: Deliquesc crystals. Sol in water, in alcohol. LD50 in mice: 485 mg/kg i.p.; 6.25 g/kg orally (Haley).
Toxicity data: LD50 in mice: 485 mg/kg i.p.; 6.25 g/kg orally (Haley)
Derivative Type: Sulfate octahydrate
Molecular Formula: Tm2(SO4)3.8H2O
Molecular Weight: 770.18
Percent Composition: Tm 43.87%, S 12.49%, O 41.55%, H 2.09%
Properties: Obtained by ppting an aq soln of thulium chloride and sulfuric acid with alc.
Derivative Type: Oxalate hexahydrate
Molecular Formula: Tm2(C2O4)3.6H2O
Molecular Weight: 710.02
Percent Composition: Tm 47.59%, C 10.15%, O 40.56%, H 1.70%
Properties: Greenish-white precipitate. Sol in aq alkali oxalates with formation of double oxalates.
