Reduction potentials beryllium

The standard reduction potential for Be2+ is the least negative of the elements in the group and by the same token beryllium is the least electropositive and has the greatest tendency to form covalent bonds. The bulk metal is relatively inert at room temperature and is not attacked by air or water at high temperatures. Beryllium powder is somewhat more reactive. The metal is passivated by cold concentrated nitric acid but dissolves in both dilute acid and alkaline solutions with the evolution of dihydrogen. The metal reacts with halogens at 600°C to form the corresponding dihalides. 

Although the entire discussion of electrochemistry thus far has been in terms of aqueous solutions, the same principles apply equaly well to nonaqueous solvents. As a result of differences in solvation energies, electrode potentials may vary considerably from those found in aqueous solution. In addition the oxidation and reduction potentials characteristic of the solvent vary with the chemical behavior of the solvent. as a result of these two effects, it is often possible to carry out reactions in a nonaqueous solvent that would be impossible in water. For example, both sodium and beryllium are too reactive to be electroplated from aqueous solution, but beryllium can be electroplated from liquid ammonia and sodium from solutions in pyridine. 0 Unfortunately, the thermodynamic data necessary to construct complete tables of standard potential values are lacking for most solvents other than water. Jolly 1 has compiled such a table for liquid ammonia. The hydrogen electrode is used as the reference point to establish the scale as in water ... 

Why are the standard reduction potentials of lithium and beryllium out of line with respect to group trends ... 

Water contains hydrogen in oxidation state +1 and oxygen in oxidation state -2. Because of that, water oxidizes chemicals with reduction potential below the potential of H /H2, such as hydrides, alkali and alkaline earth metals (except for beryllium), etc. Some other reactive metals, such as aluminum, are oxidized by water as well, but their oxides are not... 

In a retrospective study of the beryllium-processing industry, Seiler et al. (179,180) reviewed beryllium exposure measurements collected from 1950 through 1978 at five different facilities. More than 35 job titles were identified, with beryllium exposure concentration estimates based on job titles ranging from 0.12 pg/m for nurses at one facility to 22 pg/m for leach mill operators at another facility (compared with the 8-hr TWA exposure limit of 2 pg/m ). However, the authors noted that only 58% of the plant-specific job titles had at least two exposure measurements. In addition, sufficient information on individual plant processes was not available to fully characterize the potential reductions in exposure by engineering controls over time. In their analysis of 643 individual daily weighted average exposure values from 1972 to 1975, 67% of the mean breathing zone values exceeded 2 pg/m and 73% of the maximum exposures... 

---