Technetium® and

R. Colton, The Chemisty ofThenium and Technetium Wiley-Interscience, New York, 1965, pp. 20—26 R. D. Peacock, The Chemisty of Technetium and Thenium Elsevier, Amsterdam, the Netherlands, 1966, pp. 122—125. 

R. D. Peacock, The Chemisty of Technetium and Thenium Elsevier, Amsterdam, the Netherlands, 1966. 

Polynuclear Carbonyls. Several stmctures consist of dinuclear metal carbonyls as shown in stmctures (4)—(6). The metal atoms in Mn2(CO) Q, as also for technetium and rhenium, are held together by a metal—metal bond and the compound contains 10 terminal CO ligands, five coordinated to each atom. The CO ligands of Mn2(00) 0 adopt a staggered configuration as illustrated in stmcture... 

This book presents a unified treatment of the chemistry of the elements. At present 112 elements are known, though not all occur in nature of the 92 elements from hydrogen to uranium all except technetium and promethium are found on earth and technetium has been detected in some stars. To these elements a further 20 have been added by artificial nuclear syntheses in the laboratory. Why are there only 90 elements in nature Why do they have their observed abundances and why do their individual isotopes occur with the particular relative abundances observed Indeed, we must also ask to what extent these isotopic abundances commonly vary in nature, thus causing variability in atomic weights and possibly jeopardizing the classical means of determining chemical composition and structure by chemical analysis. 

In the solid state all three elements have typically metallic structures. Technetium and Re are isostructural with hep lattices, but there are 4 allotropes of Mn of which the o-fomi is the one stable at room temperature. This has a bcc structure in which, for reasons which are not clear, there are 4 distinct types of Mn atom. It is hard and brittle, and noticeably less refractory than its predecessors in the first transition series. 

E° for some manganese, technetium and rhenium couples in acid solution at 25°C... 

Table 24.3 Oxidation states and stereochemistries of manganese, technetium and rhenium...

Manganese, Technetium and Rhenium Table 24.6 Oxohalides of Group 7... 

Prior to 1940 only the naturally occurring actinides (thorium, protactinium and uranium) were known the remainder have been produced artificially since then. The transactinides are still being synthesized and so far the nine elements with atomic numbers 104-112 have been reliably established. Indeed, the 20 manmade transuranium elements together with technetium and promethium now constitute one-fifth of all the known chemical elements. 

Nucleosynthesis is the formation of elements. Hydrogen and helium were produced in the Big Bang all other elements are descended from these two, as a result of nuclear reactions taking place either in stars or in space. Some elements—among them technetium and promethium—are found in only trace amounts on Earth. Although these elements were made in stars, their short lifetimes did not allow them to survive long enough to contribute to the formation of our planet. However, nuclides that are too unstable to be found on Earth can be made by artificial techniques, and scientists have added about 2200 different nuclides to the 300 or so that occur naturally. 

Istok JD, JM Senko, LR Krumholz, D Watson, MA Bogle, A Peacock, Y-J Chang, DC White (2004) In situ bioremediation of technetium and uranium in a nitrate-contaminated aquifer. Environ Sci Technol 38 468-475. 

Nuclear medicine scans Method of body imaging that uses a radioactive tracer material (e.g., technetium and gallium) to produce body images. For example, bone scans detect uptake and cellular activity in areas of inflammation. 

Durand JP, Milcent MC, Goudard F, et al. 1994. Chemical behavior of three radionuclides (cesium, americium and technetium) and their uptake at the cystosolic level in aquatic organisms. Biochem Mol Biol Int 33(3) 521-534. 

Bearing this situation in mind we wished to describe the present status of studies on chemistry and its applications of technetium and rhenium. A part of this book was planned before the "Topical Symposium on the Behavior and Utilization of Technetium 93" was held in Sendai, Japan in March 1993, but the planning of the book in this style was accelerated after the symposium by suggestions from our friends. The editors are grateful for the cooperation from the contributes and the publisher. 

Nicolini M, Bandoli G, Mazzi U (eds) (1990) Technetium and rhenium in chemistry and nuclear medicine 3, Cortina International, Verona/Raven, New York... 

The better known rhenium(V) chemistry is of great interest, not only because it resembles the second-row congener technetium and easily permits non-radio-active model studies for technetium. 186Re and 188Re are attractive isotopes for therapeutic radiopharmaceuticals. 99mTc and 186Re can be considered to be a matched pair for diagnostics and therapy. 

---