Nomenclature
CAS number: 7440-67-7
Description and references
Zr; at. wt 91.224; at. no. 40; valence 4; also
3. Group IVB (4). Five naturally occurring isotopes: 90 (51.46%);
91 (11.23%); 92 (17.11%); 94 (17.40%); 96 (2.80%); artificial radioactive
isotopes: 81-89, 93, 95, 97-99. Occurrence in earth's crust: 0.023%.
Occurs in the minerals zircon, malacon, baddeleyite, zirkelite, eudialyte;
frequently found in the rare-earth minerals; in monazite sand. Discovered
by Klaproth in 1789; prepd by Berzelius in 1824. Prepn: Fast, Z. Anorg. Chem. 239, 145 (1938);
purification of zirconium by ion exchange columns: Ayres, J. Am. Chem. Soc. 69, 1879 (1947).
Sepn of zirconium and hafnium: Fischer et al., Angew. Chem. Int. Ed. 5, 15 (1966).
Reviews of zirconium and its compds: W. B. Blumenthal, The Chemical Behavior of Zirconium (Van Nostrand,
Princeton, 1958); Gmelins, Zirconium (8th ed.) 42, (1958) 448 pp; Larsen, “Zirconium and Hafnium
Chemistry” in Adv. Inorg. Chem. Radiochem. 13, 1-333 (1970); Bradley, Thornton, “Zirconium and Hafnium”
in Comprehensive Inorganic Chemistry vol. 3, J. C. Bailar, Jr. et al., Eds. (Pergamon
Press, Oxford, 1973) pp 419-490.
Properties
Bluish-black, amorphous powder or grayish-white
lustrous metal (platelets or flakes) of hexagonal lattice below 865°,
body-centered cubic above 865°, mp 1857°; bp 3577°. d 6.5. Brinnell
hardness: 85. Can absorb up to 10 atoms per cent of oxygen or nitrogen.
Flammable; spontaneously combustible. Reacts with hydrofluoric acid, aqua regia, hot phosphoric acid.
Not attacked by cold, very slightly attacked by hot, concd sulfuric
or hydrochloric acid; not attacked by nitric acid. Attacked by fused
potassium hydroxide or nitrate. On prolonged heating the compact
form combines with oxygen, nitrogen, carbon, and the halogens. The
powder form has a very low ignition temp and is very explosive when
mixed with oxidizing agents.Caution
Zirconium and its salts generally
have low systemic toxicity. A granulomatous disease of the skin,
particularly in the axilla, has been reported in users of a deodorant
contg sodium zirconium lactate: see E. Browning, Toxicity of Industrial Metals (Appleton-Century-Crofts,
New York, 2nd ed., 1969) pp 356-360. Consult latest Government regulations
on use in aerosol antiperspirants.Use
Pure zirconium (hafnium-free) is a valuable structural
material for atomic reactors because of its low nuclear cross-section
and high corrosion and heat resistance. Because of hafnium's high
neutron absorption characteristics, it must be removed from zirconium
which is to be used in nuclear reactors; removal unnecessary for other
commercial purposes. As an ingredient of priming or explosive mixtures;
flashlight powders; as deoxidizer in metallurgy; as “getter” in vacuum
tubes; in constructing rayon spinnerets in lamp filaments, flash bulbs.