Potassium hydroxide, valence

Now in the foregoing reactions the osmium is used in the form of its tetroxide, in which its valency is 8. The first action is that of the reducing agent, which lowers its valency to six. Then comes the formation of the osmyl derivative. For example, the preparation of potassium osmyl oxalate takes place in two stages, namely, (1) the reduction of 0s04 to OsOs, which, in the presence of the potassium hydroxide, yields potassium osmate, K20s04 and (2) interaction of the last named with 2 molecules of oxalic acid to form the osmyl derivative. These stages may be expressed as follows ... 

This paper presented evidence for the existence, in potassium hydroxide melts (0.85 w KOH) between 498 and 523 K, of reversible homogeneous nickel redox couples in which nickel exhibits valencies greater than two. The data can be interpreted by the following two simultaneous redox reactions ... 

Penta- and Hexa-aza-compounds. 3,6-Dibenzyl-l,2,4,5-tetrazine (811) undergoes a complex reaction with methanolic potassium hydroxide, giving 3-benzyl-7-methoxy-6-phenylimidazo[l,2-6][l,2,4,5]tetrazine (812), whose structure has been elucidated by X-ray analysis.Carbon-13 n.m.r. spectroscopy has been used to investigate azido-tetrazole valence tautomerism for the systems (813) and (814)" and for (815) (816) (817)." ... 

During charge the nickel hydroxide in the positive electrode is oxidized to nickel oxy-hydroxide (NiOOH) and higher valence states of nickel. Potassium and water are also incorporated into the active material as potassium hydroxide according to the following equation ... 

It is a brownish-yellow friable unstable powder, diphenyl being easily eliminated, and may be converted to the hydroxide by the action of alcohol and water. Since the production of the hydroxide takes place with ease, it is assumed that the metal is not normally tervalent, but that the operative valency electrons are derived from groups other than the usual and that the 4U electron ( potassium electron95) is not involved, thus causing the similarity of chromium triphenyl to the alkali metals, as shown by its ready conversion into the base. 

Barium reacts with metal oxides and hydroxides in soil and is subsequently adsorbed onto soil particulates (Hem 1959 Rai et al. 1984). Adsorption onto metal oxides in soils and sediments probably acts as a control over the concentration of barium in natural waters (Bodek et al. 1988). Under typical environmental conditions, barium displaces other adsorbed alkaline earth metals from MnO2, SiO2, and TiO2 (Rai et al. 1984). However, barium is displaced from Al203 by other alkaline earth metals (Rai et al. 1984). The ionic radius of the barium ion in its typical valence state (Ba+) makes isomorphous substitution possible only with strontium and generally not with the other members of the alkaline earth elements (Kirkpatrick 1978). Among the other elements that occur with barium in nature, substitution is common only with potassium but not with the smaller ions of sodium, iron, manganese, aluminum, and silicon (Kirkpatrick 1978). 

Much less work has been reported for the 6-valent elements as compared with the volume of literature for the actinides in lower valence states. Hydrated neptunium and plutonium trioxides are now known, Np03 H2O and PUO3 (0.8)H2O being readily obtained by the action of ozone on an aqueous suspension of neptunium (V) or plutonium (IV) hydroxides at 90°C. (23) Np03 2H2O is obtained in a similar manner at 18°C. (23) or by ozone oxidation of neptunium (V) in a molten lithium-potassium nitrate eutectic at 150°C. (42). 

---