Alkali metals oxidation numbers

Alkali metals Oxidation number always = +1 Li in LiCI, LijO, LiH KinKOH, K3CO3, KNO3... 

When the positions of cations and anions are interchanged, the same structure types result for the CsCl, NaCl and zinc blende type. In the case of the fluorite type the interchange also involves an interchange of the coordination numbers, i.e. the anions obtain coordination number 8 and the cations 4. This structure type sometimes is called anti-fluorite type it is known for the alkali metal oxides (Li20,..., Rb20). 

Boghosian et al. (1991) studied the solubility of earth alkali metal oxides in alkali metal-earth alkali metal chlorides and NaCl-MeCl2 melts. They found that the oxide solubility is in general very low and increases markedly with the MeCl2 concentration and with increasing atomic number of the earth alkali metal atom. The very low oxide solubility in earth alkali metal chlorides can be explained by the reaction (e.g. for the MgCl2 melts)... 

In the binary glass-forming systems of alkali metal borates, it is possible to observe change in the trend of a number of physico-chemical properties in the concentration range of approximately 20 mole % of alkali metal oxide. This phenomenon is known in the literature as boric acid anomaly , and it is due to the change in the structure of the B2O3 melt caused by the alkali metal oxide addition and is related to the ability of boron to change its coordination number. 

Krogh-Moe (1958, 1960) concluded that the change in the coordination number of boron from 3 to 4 takes place up to a content of 33 mole % of alkali metal oxide, which corresponds to the maximum concentration of 50% of four-coordinated boron. This assumption has been explicitly experimentally confirmed using the measurements of nuclear magnetic resonance carried out by Silver and Bray (1958) and Bray and O Keefe (1963). These authors found out that within the concentration range of x = 0-30 mole % of alkali metal oxide the concentration of four-coordinated boron, N, may be quite accurately expressed by the relation... 

The above-described trend is maintained up to approximately 30 mole % of alkali metal oxide. Above this concentration, non-bridging oxygen atoms arise as the result of the reverse transition of some boron atoms from the tetrahedral into the triangular coordination. The number of boron atoms in the tetrahedral coordination decreases, approaching zero at 70 mole % of the alkali metal oxide. It should be, however, noted that the picture of the structure of the melt is only approximate and differences between the liquid and crystalline phase may occur. 

Figure 15.8 shows the formulas of a number of oxides of the representative elements in their highest oxidation states. Note that all alkali metal oxides and all alkaline earth metal oxides except BeO are basic. Beryllium oxide and several metallic oxides in Groups 3A and 4A are amphoteric. Nonmetallic oxides in which the oxidation number of the representative element is high are acidic (for example, N2O5, SO3, and CI2O7), but those in which the oxidation number of the representative element is low (for example, CO and NO) show no measurable acidic properties. No nonmetallic oxides are known to have basic properties. 

Fuel cells are electrochemical devices in which fuels (e.g., hydrogen, carbon monoxide, hydrocarbons, and alkali metals), oxidants, and reaction products move into and out of a system of electrodes separated by an electrolyte. The reduction-oxidation reactions that take place generate a direct current while the materials are supplied to the cell. A number of transportation and other applications for this technology are being explored, partly because of the environmental benefits the reaction products have over those of fossil fuels. M86 fuel, a mixture of anhydrous and methyl hydrazines, is used in fuel cells including those used to generate electricity for some aircraft hydraulics systems. These fuel tanks are leak-tight, double-walled aluminium pressure vessels that contain up to 42 litres of M86. 

Cobalt has an odd number of electrons, and does not form a simple carbonyl in oxidation state 0. However, carbonyls of formulae Co2(CO)g, Co4(CO)i2 and CoJCO),6 are known reduction of these by an alkali metal dissolved in liquid ammonia (p. 126) gives the ion [Co(CO)4] ". Both Co2(CO)g and [Co(CO)4]" are important as catalysts for organic syntheses. In the so-called oxo reaction, where an alkene reacts with carbon monoxide and hydrogen, under pressure, to give an aldehyde, dicobalt octacarbonyl is used as catalyst ... 

By heating the metal with appropriate oxides or carbonates of alkali or alkaline earth metals, a number of mixed oxides of Ru and Os have been made. They include NasOs Og, LifiOs Og and the ruthenites , M Ru 03, in all of which the metal is situated in octahedral sites of an oxide lattice. Ru (octahedral) has now also been established by Ru Mdssbauer spectroscopy as a common stable oxidation state in mixed oxides such as Na3Ru 04, Na4Ru2 07, and the ordered perovskite-type phases M Ln Ru Og. 

Interaction between niobium oxide and fluorides, chlorides or carbonates of alkali metals in an ammonium hydrofluoride melt, yielded monooxyfluoroniobates with different compositions, MxNbOF3+x, where they were subsequently investigated [123-127]. According to DTA patterns of the Nb205 - 6NFL HF2 - 2MF system, (Fig. 18) a rich variety of endothermic effects result from the formation of ammonium monooxyfluoroniobate, its thermal decomposition and its interaction with alkali metal fluorides. The number of effects decreases and separation of ammonium ceases at lower temperatures and when going from lithium to cesium in the sequence of alkali metal fluorides. 

A slight but systematic decrease in the wave number of the complexes bond vibrations, observed when moving from sodium to cesium, corresponds to the increase in the covalency of the inner-sphere bonds. Taking into account that the ionic radii of rubidium and cesium are greater than that of fluorine, it can be assumed that the covalent bond share results not only from the polarization of the complex ion but from that of the outer-sphere cation as well. This mechanism could explain the main differences between fluoride ions and oxides. For instance, melts of alkali metal nitrates display a similar influence of the alkali metal on the vibration frequency, but covalent interactions are affected mostly by the polarization of nitrate ions in the field of the outer-sphere alkali metal cations [359]. 

Mendeleev, Dimitri, 104,107 Mendelevium, oxidation number, 414 Mercuric perchlorate, 237 Mercurous perchlorate, 237 Mercury, oxidation numbers, 414 Mercury (planet), data on, 444 Metabolism, oxidative, 429 Metallic alloys, 309 bond, 303 elements. 303 radius, 380 substances, 81 Metals alkali, 94... 

---