PALLADIUM (Palladium, Pd) — chemical element VIII of group of a periodic system of D. Mendeleyev, belongs to platinum metals, in medicine is used generally in stomatology. The item serves as the catalyst of many chemical reactions; this its property is used in organicheskokhm synthesis pharm, the industries, in synthetic rubber production. The item is applied also in electrical equipment, to production of jewelry. Radioisotope 103 Pd (half-life of 17 days).
Connections P. are characterized relatively by a hypotoxicity, however, as well as connections of others platinum metals (see), can cause an occupational disease — platinoz.
The hypotoxicity of compounds of palladium for an organism is explained by strong binding of this metal proteins through nitrogen and sulfur the initial stages of engagement with fabrics. Unlike complex compounds of platinum complex connections P. have no carcinostatic activity. The item causes hydrolysis of phosphodiester bonds and a denaturation of molecules DNA.
Crust contains 1•10 — 6 weight. % of the Item. Minerals, P. is a part to-rykh, represent its connections with lead, tin, arsenic, sulfur, bismuth, tellurium. Extract palladium from native platinum, waste products of nickel and copper, etc.
Sequence number 46, atomic weight (weight) 106,44. The item has 6 stable and 18 artificial radioisotopes. It represents silvery white metal with a density of 12,02 g/cm 3 (t°20 °); t ° pl 1552 °; t ° kip 3980 °.
The item is chemically resistant. Is oxidized concentrated nitric and sulfuric to-tami during the heating. In connections P. usually happens bivalent (+2), but can show valencies +3 and +4. The item forms a large number complex connections (see), has high affinity to hydrogen (1 volume of P. connects up to 900 volumes of hydrogen); this property P. is used for industrial receiving hydrogen.
Bibliography: 3akharova I. A., etc. Anti-phage activity of complex compounds of platinum and palladium, Coordination chemistry, t. 2, No. 12, page 1642, 1976; Village of Livingston. Chemistry of ruthenium, rhodium, palladium, osmium, iridium, platinum, the lane with English, M., 1978; Nekrasov B. V. Fundamentals of the general chemistry, t. 3, M., 1970. See also bibliogr, to St. Platinum metals .
A. V. Babkov.