Group 7 element

Group 7 of the periodic table, as defined by IUPAC, includes the elements manganese, technetium, rhenium, and bohrium. These elements are all located in the d-block, classifying them as transition metals, and the group is occasionally referred to as the manganese family due to its lightest member. Unlike some other groups, it lacks a widely recognized trivial name.

The elements exhibit a general tendency toward a +7 oxidation state, though this pattern is less consistent than in earlier groups. Their electron configurations, particularly in the outermost shells, influence their chemical behavior and show periodic trends. In terms of natural abundance, manganese is relatively common, while rhenium is scarce; technetium is found only in trace amounts, and bohrium does not occur naturally, being produced synthetically.

Physically, the group 7 elements generally crystallize in a hexagonal close-packed structure, with manganese being the exception as it adopts a body-centered cubic arrangement. Bohrium is predicted to share the hcp structure. Chemically, all members readily display the +7 oxidation state, which becomes more stable as the group is descended. Technetium also exhibits a stable +4 state, and rhenium shows stable +4 and +3 states; bohrium may similarly manifest lower oxidation states.

The +7 state is often expressed in oxyanions like permanganate, pertechnetate, and perrhenate, with a corresponding perbohrate ion possible, though bohrium(VII) is likely unstable in water and prone to reduction to bohrium(IV). Manganese forms several oxides, including MnO, Mn3O4, Mn2O3, MnO2, and Mn2O7, with MnO2 being a key ore and battery component. Technetium’s main oxides are TcO2 and Tc2O7, the latter a rare molecular binary metal oxide. Rhenium oxides include ReO2, Re2O7, and a trioxide, with Re2O7 serving as the precursor for most rhenium compounds.