3646. Erbium

Nomenclature

CAS number: 7440-52-0

Description and 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. Naturf"or. F"orh. 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).

Derivative

Oxide.

Nomenclature

Erbia.
Er2O3; mol wt 382.52.
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°.

Derivative

Hydroxide.
Er(OH)3; mol wt 218.28.
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

Chloride.
ErCl3; mol wt 273.62.
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).

Derivative

Bromide.
ErBr3; mol wt 406.97.
Er 41.10%, Br 58.90%.

Properties

Nonahydrate, deliquesc rose crystals.

Derivative

Nitrate.
Er(NO3)3; mol wt 353.27.
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).