Title: Erbium
CAS Registry Number: 7440-52-0
Literature References: Er; at. wt 167.26; at. no. 68; valence 3. Rare earth metal of the yttrium group; member of the lanthanide series. Naturally occurring isotopes (mass numbers): 162 (0.14%); 164 (1.61%); 166 (33.6%); 167 (22.95%); 168 (26.8%); 170 (14.9%). Known artificial radioactive isotopes: 147; 148; 150-161; 163; 165; 169; 171-173. Abundance in earth's crust: 2.47-3.5 ppm. Occurs in small quantities in all the rare earth minerals; main sources: xenotime, fergusonite, gadolinite, euxenite, polycrase, blomstrandine. Discovery: Mosander, Skand. Naturför. Förh. 3, 387 (1842); Philos. Mag. [3] 23, 241 (1843). Separation of oxide: James, J. Am. Chem. Soc. 32, 517 (1910); 34, 757 (1912); Hofmann, Burger, Ber. 41, 308 (1908); Prandtl, Z. Anorg. Chem. 198, 157 (1931). Sepn by ion-exchange: Spedding et al., J. Am. Chem. Soc. 69, 2812 (1947); 76, 2557 (1954). Prepn of the metal: Klemm, Bommer, Z. Anorg. Chem. 213, 138 (1937). Prepn of chloride, bromide: Jantsch et al., Z. Anorg. Chem. 207, 353 (1932). Radioactivity induced by neutron bombardment: Sugden, Nature 135, 469 (1935); McLennan, Rann, ibid. 136, 831 (1935). Spectrum: Eder, Ber. Wien. Akad. [2a] 124, 790 (1915); deGramont, Compt. Rend. 171, 1106 (1920); Mott, McDonald, Trans. R. Soc. Can. Sect. 3 21, 230 (1927). Natural isotopic composition: Hayden et al., Phys. Rev. 77, 299 (1950). Toxicity study: Haley, J. Pharm. Sci. 54, 663 (1965). Reviews 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: Dark-gray metallic powder; hexagonal close-packed crystal lattice. d 9.066. mp 1529°. bp 2868°. Heat of fusion: 19.90 kJ/mol. Heat of sublimation (25°): 317.10 kJ/mol. E°(aq) Er3+/Er -230 V (calc). Similar to the other rare earth metals, possesses two reduction potentials 1.770 and 1.875 volts (ref to the normal calomel electrode), Noddack, Brukl, Angew. Chem. 50, 362 (1937).
Melting point: mp 1529°
Boiling point: bp 2868°
Density: d 9.066
Derivative Type: Oxide
Additional Names: Erbia
Molecular Formula: Er2O3
Molecular Weight: 382.52
Percent Composition: Er 87.45%, O 12.55%
Properties: Pinkish powder changing into cubic crystals on heating at 1300°; d 8.64; sp heat 0.065; prepd by igniting the oxalate or basic nitrate. Readily sol in acids. Soly in water: 1.28´10-5 g-mol/l at 29°.
Density: d 8.64
Derivative Type: Hydroxide
Molecular Formula: Er(OH)3
Molecular Weight: 218.28
Percent Composition: Er 76.63%, O 21.99%, H 1.39%
Properties: Pale pink gelatinous ppt. Prepd by action of alkali hydroxide on a soln of erbium nitrate.
Derivative Type: Chloride
Molecular Formula: ErCl3
Molecular Weight: 273.62
Percent Composition: Er 61.13%, Cl 38.87%
Properties: Hexahydrate, deliquesc crystals. Sol in water; slightly sol in alcohol. Dehydrated by heating in a stream of hydrogen chloride. Anhydr form is pinkish powder, d 4.1. LD50 in mice (mg/kg): 535 i.p.; 6.2 orally (Haley).
Density: d 4.1
Toxicity data: LD50 in mice (mg/kg): 535 i.p.; 6.2 orally (Haley)
Derivative Type: Bromide
Molecular Formula: ErBr3
Molecular Weight: 406.97
Percent Composition: Er 41.10%, Br 58.90%
Properties: Nonahydrate, deliquesc rose crystals.
Derivative Type: Nitrate
Molecular Formula: Er(NO3)3
Molecular Weight: 353.27
Percent Composition: Er 47.35%, N 11.89%, O 40.76%
Properties: Pentahydrate, reddish, deliquesc crystalline solid. Loses 4 mols of water on heating to 130°. LD50 of hexahydrate in female rats (mg/kg): 230 i.p.; 35.8 i.v. (Haley).
Toxicity data: LD50 of hexahydrate in female rats (mg/kg): 230 i.p.; 35.8 i.v. (Haley)
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