Other Transition-metal Elements

A Mdssbauer resonance is known in at least one isotope of fourteen tran sition metals in addition to iron. However, none has been extensively used up to the present time. Several of them present extreme difficulties in measurement, but as this chapter will show, sufficient background information has been collected to assess the feasibility of chemical application. 

The elements will be discussed in the order of increasing atomic number in the Periodic Table, i.e. nickel, zinc, technetium, ruthenium, silver, hafnium, tantalum, tungsten, rhem um, osmium, iridium, platinum, gold, and mercury. Full numerical data of the relevant nuclear properties are summarized, as for other elements, in Appendix 1. 

The 67-4-keV resonance of iNi was first reported in 1961 by Obenshain and Wegener [1], who used the /3-decay of 99-minute Co to populate the excited level (see Fig. 16.1). The source in these initial experiments at 80 K was a 

Very similar results were obtained using Coulomb excitation of a nickel foil target by 25-MeV oxygen ions [3], and the Coulomb-recoil implantation technique has also been demonstrated [4]. 

A second Co preparation is Ni(y,p) Co, and this gives good results [4, 5], A 15% chromium-nickel alloy is cubic, non-magnetic at 80 K, and 

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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. 

Technetium is one of the few artificially produced elements that has practical industrial applications. One is that a very small amount (55-ppm) added to iron creates a corrosion-resistant alloy metal. This property is shared with many of the other transition metallic elements, but not with other artificially produced elements that have higher atomic numbers and are radioactive. 

Zeolites and zeotypes can be defined as microporous crystalline structures (Figure 1 and Table 1) in which the framework is formed by tetrahedral of silica, in which there is isomorphic substitution with trivalent or tetravalent elements such as for instance Al, Ge, B, Fe, Cr, Ge, Ti, etc. [1]. Similar types of structure can also be achieved with the framework formed by Al and P, with or without other transition metal elements [2]. These types of structure are denoted as AlPOs, SAPOs, and MEAPOs, depending on the composition of the framework [3]. 

So far, only the hexanuclear clusters have been studied. What about different nuclearity clusters of other transition metal elements In other words, is it possible that a new chemistry within transition metal clusters has just started ... 

The hole-doped perovskite manganese oxides with general formula Lni.xAxMnOs (Ln= La, Pr, Nd A= Ca, Sr, Ba, Pb x<0.5) draw considerable attention in the late 1990 s due to their colossal magneto-resistance (CMR) effect at low temperatures (Rao, 1998). In the search for new CMR materials it was observed that doping on Mn site by other transition metal elements, such as Cr, Fe, Co and Ni, was an effective way to obtain new materials, which... 

In the preceding subsection, we discussed the phase relationships in the system M = M = Fe. In the present section, we describe the systems where M or M is substituted by other transition metal elements. Since thermogravimetric methods can not be applied to such systems, the phase relationships shown here were determined by the quenching method. We also refer to the systems including Iu203 instead of rare earth oxides. 

Since this work was carried ont, further recent progress has been made using PM6 to extend this work to comparative studies of other transition metal elements typically used in the CCVD processes described earlier [52]. The results from PM6 are broadly consistent with AMI in the case of molybdenum, but cover a wider range of transition metals including iron, nickel, and cobalt. 

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