Group 7 technetium and rhenium

The heavier group 7 metals, Tc and Re, are less reactive than Mn. Technetium does not occur naturally (see Section 22.2). The bulk metals tarnish slowly in air, but more finely divided Tc and Re burn in O2 (equation 22.61) and react with the halogens (see below). Reactions with sulfur give TCS2 and ReS2. 

The metals dissolve in oxidizing acids (e.g. cone HNO3) to give HTCO4 (pertechnetic acid) and HRe04 (perrhenic acid), but are insoluble in HF or HCl. 

Technetium and rhenium exhibit oxidation states from 0 to +7 Table 19.3), although M(II) and lower states are stabilized by 7r-acceptor ligands such as CO and will not be 

Technetium and rhenium exhibit oxidation states from 0 to +7 (Table 19.3), although M(II) and lower states are stabilized by 7r-acceptor ligands such as CO (see Box 22.7) and will not be considered further in this section. The chemistry of Re is better developed than that of Tc, but interest in the latter has expanded with the current use of its compounds in nuclear medicine. There are significant differences between the chemistries of Mn and the heavier group 7 metals  

Rationalize why the Mo—Mo bond length increases ( 7pm) when M02(p.-O2CR)4 (R = 2,4,6-Pr3C6H2 undergoes a 1-electron oxidation. 

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

Manganese is a reactive metal that has several oxidation states (2, 3, 4, 6, and 7) that are responsible for its varied chemical compounds. The chemical and physical properties of manganese are similar to the properties of its companions in group 7—technetium ( jTc) and rhenium ( jRe). 

As the central member of the triad of metals in group 7, technetium (period 5) has similar physical and chemical properties as its partners manganese (period 4) above it and rhenium (period 6) below it. The sizes of their atomic radii do not vary greatly Mn = 127, Tc = 136, and Re = 137. Neither does their level of electronegativity vary significantly Mn = 1.5, Tc =... 

Electrochemistry of the Group 7 Elements Manganese, Technetium, and Rhenium... 

Group 7- In order of increasing alomie number. Ihese are manganese, technetium, and rhenium. Manganese and rhenium have two electrons in their ouler shells technetium lias one electron in its outer shell. Although... 

The Group 7 metals technetium and rhenium have not been applied to the problem of oxidation chemistry to the level of their Group 6 and Group 8 counterparts. This is understandable in light of their relative scarcity. Technetium is a synthetic element, recovered as a fission by-product from uranium.3 "Tc is radioactive (/3 decay, 0.3 MeV, tv2 = 2.14 X 10s years) and its use even in the laboratory requires the appropriate safety precautions. Rhenium is not plagued by either issue, yet it is still a relatively rare element, present at only an estimated 0.001 ppm in the Earth s crust. It is... 

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