From Big Medical Encyclopedia

RUTHENIUM (Ruthenium, Ru) — metal from the second triad of the VIII group of a periodic system of elements of D. I. Mendeleyev.

At. number 44, at. weight (weight) 101,07. Exists in all valent forms from I to VIII and has nulvatency in carbonyls. The most stable valence states of III and IV. Density 12,2; t°pl 2250 °; t°kip ok - 4900 °, is resistant to effect of acids. R.'s maintenance in crust is estimated in 5*10 - 7  %. Isotopes P. are known from 92 Ru to 112 Ru; from them 7 stable (with mass numbers 96,98 — 102,104) and 14 radioactive. In scientific research as a tag use radioisotopes 97 Ru with half-life (T1/2) of 2,88 days, 103Ru (T1/2 = 40 days) and 106Ru (T1/2 = 367 days). At disintegration 103Ru it is formed affiliated radioactive 103MRh, and at disintegration 106R and — affiliated radioisotope 106Rh. From cleavage products uranium (see) it is possible to allocate 103Ru and 106Ru. 103Ru receive also in the nuclear reactor (see. nuclear reactors ). 97Ru it is formed or at radiation of molybdenum and - particles on a cyclotron or on reaction 96Ru (n, scale) 97Ru in the nuclear reactor. In medicine consider perspective use 97Ru, to-ry breaks up by electron capture. Disintegration 97 R is also followed by emission at - quanta with energy 0,216 Mei (86% for the act of disintegration), 0,325 Mev (10,2%), 0,461 Mev (0,12%), 0,569 Mev (0,86%).

According to physical characteristics 97Ru it is convenient for inclusion in structure radio pharmaceuticals (see) in this connection searches of the connections 97Ru suitable for use as such drugs are conducted. At the same time the stablest complex connections form two - and trivalent Ruble. Applicators with radionuclides 106Ru + 106Rh apply for radiation therapy (see) malignant tumors of an eye.

According to standards of radiation safety (NRB-76) on radio toxicity 97Ru and 103Ru carry to group of radiation hazard In, and long-living isotope 106Ru — to group B, i.e. open drugs with these radioisotopes activity 10 and 1 mkkyur (370 and 37 kBq) respectively can be in a workplace without the permission of bodies of State sanitary inspection. Radioactive R. comes to the atmosphere at nuclear explosions and operation of nuclear power stations. An admissible limit of annual intake of various radioisotopes P. through a respiratory organs from 1,4 to 21 mkkyur (see. Marginal dose of radiation , Radiation safety ). Critical body for soluble compounds of radioisotopes P. is went. - kish. the path, and for insoluble compounds — in some cases went. - kish. path and lungs.

See also Isotopes .

Bibliography: Materials on toxicology of radioactive materials, under the editorship of. A. A. Le-taveta and E. B. Kurlyandskoy, M., 1957.

A. B. Malinin, V. V. Sedov.