Title: Neodymium
CAS Registry Number: 7440-00-8
Literature References: Nd; at. wt 144.242; at. no. 60; valences 2, 3, 4. A lanthanide; belongs to the cerium group of rare earth metals. Naturally occurring isotopes (mass numbers): 142 (27.13%); 143 (12.18%); 144 (23.80%), radioactive, T½ 2.1 ´ 1015 years, a-emitter; 145 (8.30%); 146 (17.19%); 148 (5.76%); 150 (5.64%). Known artificial radioactive isotopes: 127-141; 147; 149; 151; 152. Abundance in earth's crust: 24-40 ppm. Commercially important sources are the rare earth minerals monazite and bastnaesite; also found in cerite and gadolinite. Discovered by von Welsbach in 1885. Sepn from Pr: F. H. Spedding et al., J. Am. Chem. Soc. 69, 2786 (1947); 76, 2557 (1954); Kauffman, Blank, J. Chem. Educ. 37, 156 (1960); from other rare earths: Spedding et al., J. Am. Chem. Soc. 69, 2812 (1947). Metal prepd by electrolysis of the chloride: Matignon, Compt. Rend. 131, 891 (1900); Sieverts, Roell, Z. Anorg. Chem. 150, 261 (1926); by reduction of the chloride: Bommer, Hohmann, ibid. 248, 357 (1941). Spectrum: Alberston et al., Phys. Rev. 61, 167 (1942). 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. Review of toxicology: T. J. Haley, J. Pharm. Sci. 54, 663-670 (1965). Brief review of properties: G. T. Seaborg, Radiochim. Acta 61, 115-122 (1993).
Properties: Silver-white metal, becomes yellowish on exposure to air. Crystalline forms: hexagonal a-form, d 7.003, transforms to b-form at 868°; body-centered cubic b-form, d 6.80, exists at >868°. mp 1021°. bp 3074°. Heat of fusion: 7.134 kJ/mol. Heat of sublimation (25°): 327.6 kJ/mol. E°(aq) Nd3+/Nd -2.44 V (calc). Experimental reduction potentials (referred to a normal calomel electrode): -1.870, -1.960 V: Noddack, Brukl, Angew. Chem. 50, 362 (1937). Reacts slowly with cold water; rapidly on heating.
Melting point: mp 1021°
Boiling point: bp 3074°
Density: d 7.003; d 6.80
Derivative Type: Oxide
Molecular Formula: Nd2O3
Molecular Weight: 336.48
Percent Composition: Nd 85.74%, O 14.26%
Literature References: Commercial uses: Pings, Colo. Sch. Mines, Miner. Ind. Bull. 12, no. 2 (1969) 19 pp.
Properties: Blue powder, hexagonal structure, exhibits a slightly red fluorescence. Prepd by heating the hydroxide, carbonate, nitrate or oxalate. Very stable. Sol in dil acids; soly in water: 5.7´10-6 g-mol/l at 29°.
Derivative Type: Hydroxide
Molecular Formula: Nd(OH)3
Molecular Weight: 195.26
Percent Composition: Nd 73.87%, O 24.58%, H 1.55%
Properties: Bluish or pink precipitate; on heating at 300-350° is converted into 2Nd2O3.3H2O, grayish-brown; on further increase in temp is converted into Nd2O3.H2O.
Derivative Type: Chloride
Molecular Formula: NdCl3
Molecular Weight: 250.60
Percent Composition: Nd 57.56%, Cl 42.44%
Properties: Large purple prisms. Sol in water, in alcohol. Forms addition compds with ammonia. A hexahydrate is obtained from the aq soln; the hydrate is very sol in water (2.46 parts per 1 part of water); mp 124°. LD50 in mice (mg/kg): 4000 s.c., 348.3 i.p.; in male mice (mg/kg): 600 i.p., 5250 orally; in rats (mg/kg): 150-250 i.p.; in guinea pigs (mg/kg): 70 i.v., 139.6 i.p.; in rabbits (mg/kg): 200-250 i.v. (Haley).
Melting point: mp 124°
Toxicity data: LD50 in mice (mg/kg): 4000 s.c., 348.3 i.p.; in male mice (mg/kg): 600 i.p., 5250 orally; in rats (mg/kg): 150-250 i.p.; in guinea pigs (mg/kg): 70 i.v., 139.6 i.p.; in rabbits (mg/kg): 200-250 i.v. (Haley)
Derivative Type: Sulfate
Molecular Formula: Nd2(SO4)3
Molecular Weight: 576.67
Percent Composition: Nd 50.03%, S 16.68%, O 33.29%
Properties: Pinkish needles; prepd by heating the oxide with concd sulfuric acid. Heat of formation 57.2 kcal. Sol in water; heat of soln 36.5 kcal. Is dec at 700-800°. Forms several double salts. A penta-, an octa-, and a pentadecahydrate have been prepared.
Derivative Type: Nitrate
Molecular Formula: Nd(NO3)3
Molecular Weight: 330.26
Percent Composition: Nd 43.68%, N 12.72%, O 43.60%
Properties: Penta- and hexahydrates; prepd by adding the oxide to nitric acid. LD50 (hexahydrate) in female mice (mg/kg): 270 i.p.; in female rats (mg/kg): 270 i.p., 2750 orally, 6.4 i.v.; in male rats (mg/kg): 66.8 i.v. (Haley).
Toxicity data: LD50 (hexahydrate) in female mice (mg/kg): 270 i.p.; in female rats (mg/kg): 270 i.p., 2750 orally, 6.4 i.v.; in male rats (mg/kg): 66.8 i.v. (Haley)
Use: Oxide as glass coloring agent; in glass filter plate laminated on color TV tubes to improve contrast and brightness; in lasers. Alloyed with iron and boron to produce powerful permanent magnets. |