Transition elements iron triad

The transition elements iron, cobalt, and nickel comprise the iron triad. Iron, with an annual worldwide production of more than 1.1 billion metric tons, is the most important metal in modern civilization. It is widely distributed in Earth s crust at an abundance of 4.7%. The major commercial use of iron is to make steel (see Section 23-3). 

Most of the transition elements do not react with strong acids, such as HCl and H2SO4. Some do have negative standard reduction potentials for the reaction M"+ -I- ne - M, and liberate hydrogen from hydrochloric acid. These include Mn, Cr, and the iron triad. Silver, gold, the palladium triad, and the platinum triad, the so-called noble metals, are especially inert to acids, both to the nonoxidizing species, such as hydrochloric and hydrofluoric acids, and to the oxidizing acids, such as nitric acid. 

Kuz ma, Yu.B., Ya.F. Lomnitskaya and S.V. Oryshchyn, 1986a, The interaction of phosphorus with transition metals of IVa-Vla group elements and iron triad metals, in Stable and Metastable Phase Equilibria in Metallic Systems, ed. M.E. Drits (Nauka, Moscow) p. 12-18. In Russian. 

General Properties 23-2 Principles of Extractive Metallurgy 23-3 Metallurgy of Iron and Steel 23-4 First-Row Transition Elements Scandium to Manganese 23-5 The Iron Triad Iron, Cobalt, and Nickel... 

The iron triad elements (Fe, Co, and Ni) exhibit a variability in oxidation state with +2 the most common. Like other transition elements these metals form compounds with carbon monoxide called metal carbonyls. 

Symbol Ni atomic number 28 atomic weight 58.693 a transition metal element in the first triad of Group VIll(Group 10) after iron and cobalt electron configuration [Ar]3d 4s2 valence states 0, -i-l, +2, and -f-3 most common oxidation state +2 the standard electrode potential, NF+ -1- 2e Ni -0.237 V atomic radius 1.24A ionic radius (NF+) 0.70A five natural isotopes Ni-58 (68.08%), Ni-60 (26.22%), Ni-61 (1.14%), Ni-62 (3.63%), Ni-64 (0.93%) nineteen radioactive isotopes are known in the mass range 51-57, 59, 63, 65-74 the longest-lived radioisotope Ni-59 has a half-life 7.6x10 years. 

Cobalt. The speciation of radiocobalt has been selected for discussion in this chapter because it exemplifies an element for which much information already exists regarding its stable chemical speciation, yet there are additional species which have become environmentally important as a result of the activities of the nuclear industry Cobalt, the middle member of the first triad of group VIII transition metals in the Periodic Table (iron, cobalt, nickel), is most stable in the divalent state when in simple compounds. Studies of radionuclide releases from nuclear power plants under tropical conditions in India seem to indicate that... 

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