Cobalt ionization energy

Identify the element with the higher first ionization energy in each of the following pairs (a) manganese and cobalt ... 

C08-0023. Iron and cobalt form compounds that can be viewed as containing cations, but nickel does not. Use the ionization energies in Appendix C to predict which other transition metal elements are unlikely to form stable cations with charges greater than +2. 

The crystal held model can also be used to account For the stability of particular oxidation states. In aqueous solution Co(lll) is unstable with respect to reduction by water to form Co(Il)- Although there are several energy terms involved, this may be viewed as a reflection of the high third ionization energy of cobalt. If various moderate-to-strong field ligands are present in the solution, however. theCo(IIl)ion is perfectly stable. In fact, m some cases it is difficult or impossible to prevent the oxidation of Co(ll) to Coflll). 

T n 1962 the U. S. Army opened at its Natick Laboratories in Natick, Mass., the world s largest irradiation laboratory (2) for preserving foods by ionizing energy (Figure 1). This laboratory is unique in that, in addition to having two radiation sources, a 24-m.e.v., 18-kw. electron linear accelerator and a 1,250,000-curie cobalt-60 isotope source, it includes a food development-preparation laboratory and an experimental development kitchen (Figure 2). 

The increased ionization energies of the heavier transition metals should not be unexpected by anyone who has had a modicum of laboratory experience with any of these elements. Although none of the coinage metals is very reactive, gold has a well-deserved reputation for being less reactive than copper or silver iron, cobalt, and nickel rust and corrode, but osmium, indium, and platinum are noble and unreaclive and therefore are used in jewelry platinum wires are the material of choice fior flame tests without contamination and one generates hydrogen with zinc and simple adds, not with mercury. 

In the rhodium case, considerable back donation appears to occur from the metal aj + a2 (e2) levels to the CO ligands as these orbitals show a greater ionization energy than the cpej orbitals. In the cobalt compound the I.E. ordering is the more conventional e2 < e t. 

Which has the largest ionization energy, platinum, an element sometimes used in dental crowns, or cobalt, an element that provides a bright blue color to pottery ... 

For example, the sum of the first three ionization energies for copper is 6258 kJ mol and the sum of the first three ionization energies for cobalt is 5640kJ moT. Therefore cobalt(iii) compounds may be more thermodynamically stable than copper(iii) compounds. This prediction is confirmed, with stable cobalt(iii) compounds being common and copper(iii) ions being rare and only found in a small number of copper-containing compounds (see Chapter 22 on the accompanying website) and some proteins. 

The first ionization energies of iron, cobalt, nickel, and the first three platinum metals are all about the same, but the first ionization energies of osmium, iridimn, and platinum are substantially greater. Suggest an explanation for this observation. 

For cobalt ferrite, CoFe204, the energy effect in the valency reaction Co(II) + Fe(III) —> Co(III) -H Fe(II) has been calculated to be 1.35 eV from the ionization potentials and crystal-field stabilization effects. The combination Co(II) + Fe(III) is the ground state. For titanium in Fe203 the following reaction is of importance... 

The application of electrospray ionization (ESI) to macromolecules was first described by Yamashita and Fenn in 1984, and he later applied this technique to the study of proteins in 1988. In ESI, charged droplets of protein were produced and the solvent was stripped away, leaving only the free protein ion. In 1987, Tanaka demonstrated that laser pnlses from a low-energy nitrogen laser could be used to ionize proteins from a surface. As described in a paper presented during the Second Japan-China Joint Symposium on Mass Spectrometry, proteins are desorbed from a glycerol matrix containing cobalt powder. The cobalt powder was necessary to increase absorption of the laser photons. ... 

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