Anions manganate

Manganates V f), [MnOJ", permanganates. Dark purple tetrahedral anion (electrolyte oxidation of [Mn04]. Powerful oxidizing agent... 

The Stock Oxidation-Number System. Stock sought to correct many nomenclature difficulties by introducing Roman numerals in parentheses to indicate the state(s) of oxidation, eg, titanium(II) chloride for TiCl2, iron(II) oxide for FeO, titanium(III) chloride for TiCl, iron(III) oxide for Fe203, titanium(IV) chloride for TiCl, and iron(II,III) oxide for Fe O. In this system, only the termination -ate is used for anions, followed by Roman numerals in parentheses. Examples are potassium manganate(IV) for K2Mn02, potassium tetrachloroplatinate(II) for K PtCl, and sodium hexacyanoferrate(III) for Na3Fe(CN)3. Thus a set of prefixes and terminations becomes uimecessary. 

Recent data provided by Cocke et a/.174,175 in an RBS study of the distribution of heavy anions (tungstates, molybdates, manganates) yield unusual oscillatory anion profiles. 

Although metal ions do not catalyze the decarboxylation of monocarboxylic acids in solution, a variety of metal ions catalyze the decarboxylation of oxaloacetic acid anion, leading to the formation of pyruvic acid (27). The metal ions involved were cupric, zinc, magnesium, aluminum, ferric, ferrous, manganous, and cadmium, approximately 10-2 to 10-3 M (27). Of these, the aluminum, ferric, ferrous, and cupric ions were the most efficient sodium, potassium, and silver ions were inactive. This process involves the decarboxylation of a / -keto acid, which undergoes a relatively facile uncatalyzed decarboxylation. However, not every decarboxylation of a / -keto acid is catalyzed by metal ions—only those... 

The cyclic manganate(V) diester anion 57 formed in a [3 + 2]-cycloaddition is believed to be the intermediate in the oxidation process434 (Scheme 9.9). This intermediate may be formed through the rearrangement of oxametallacyclobutane 58 resulting from a [2 + 2]-cycloaddition,442,443 Experimental observations indicate that the product 1,2-diol is formed as a result of the gradual reduction of the cyclic... 

We have looked only at acid solutions since relatively few simple cations M +(aq) can exist in appreciable concentrations at alkaline or even neutral pH values. Note that in Fig. 5.4, Mn(IV) is represented by Mn02(s) and not by Mn4+(aq), while the higher oxidation states are represented by anionic species. The relative stabilities of the oxidation states are strongly pH-dependent. Thus Mn2+(aq) is quite difficult to oxidise to Mn3+(aq) in acid solution. When a manganous salt is dissolved in water and the pH adjusted to about 10, Mn(OH)2 is precipitated. If allowed to stand in contact with air, this undergoes oxidation to an Mn(III) hydrated oxide usually (but erroneously) formulated as Mn(OH)3 ... 

A range of salts of the anion has been described and it is known as a ligand—one notable example being (H3 0)2 [Mnlv (Mn04)6] H2 O, which is one of the products of dehydration of HMn04 in water. An X-ray analysis of the potassium and calcium salts has given Mn—O at 1.63 A—somewhat shorter, as expected, than in the manganate(VI) species. 

Manganese(VI) compounds contain the manganate(VI) MnO " anion. This is stable in alkaline solutions, and possesses a green colour. Upon neutralization a disproportionation reaction takes place manganese dioxide precipitate and manganate(VII) (permanganate) ions are formed ... 

Mn XANES K spectra are practically identical and independent of nature of cations in the compounds. Studying the pre-threshold structure of the spectra (Figure 3) shows that the system of non-occupied MO in the Mn clusters does not vary in the series of the manganates. It is evident that any noticeable covalent interaction between the Mn complex anion and its cation environment is absent. 

Based on the spectra studied, it is concluded that the interaction between cation and anion sublattices in the manganates is mainly electrostatic interaction. 

In certain cases both anions and cations of the same metal are concerned for such systems the equilibria, and hence the equations for the electrode potential, involve hydrogen ions. An instance of this kind is the permanganate-manganous ion system, viz.,... 

Korkisch, J., Hiibner, H., Steffen, I., Arrhenius, G., Fisk, M., Frazer, J. Chemical analysis of manganes modules I. Determination of seven main and trace constituents after anion-exchange separation. Anal Chim. Acta 83, 83 (1976)... 

Manganese and cobalt compounds are particularly effective in decomposing hydroperoxides (eqs. (17) and (19)) and hence are frequently used as oxidation catalysts [47]. In spite of their similar abilities in this regard, the results of their use in a given instance can be quite different. Manganous ions are reported to have a pronounced ability to reduce peroxy radicals directly to peroxy anions (eq. (20)) [50] ... 

The cationic iron and manganese complexes 25 and 27 were similarly prepared by the reaction of the chloro- (24) or methoxy-substituted (26) cyclopropenylium ions with anionic carbon-ylferrate and manganate complexes. 

In cases of confusion in the names of acids or anions such as the manganites and manganates and the ferrites and ferrates, the use of the Stock system with an invariable -ic or -ate ending, followed by the Roman numeral, offers a satisfactory solution ... 

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