Ozonide ion

Oxygen Compounds. Although hydrogen peroxide is unreactive toward ozone at room temperature, hydroperoxyl ion reacts rapidly (39). The ozonide ion, after protonation, decomposes to hydroxyl radicals and oxygen. Hydroxyl ions react at a moderate rate with ozone (k = 70). 

The ozonides are characterized by the presence of the ozonide ion, O - They are generally produced by the reaction of the inorganic oxide and ozone (qv). Two reviews of ozonide chemistry are available (1,117). Sodium ozonide [12058-54-7] NaO potassium ozonide [12030-89-6] 35 rubidium ozonide [12060-04-7] RbO and cesium ozonide [12053-67-7] CsO, have all been reported (1). Ammonium ozonide [12161 -20-5] NH O, and tetramethylammonium ozonide [78657-29-1/, (CH ) NO, have been prepared at low temperatures (118). 

The ozonide ion has widely spaced energy levels, and to first order the g values are not influenced by the host lattice or the surface. Thus, the absolute values of the g values are useful in the identification of the ion. These g values, along with the hyperfine coupling constants, are given in Table I. The three sets of hyperfine constants indicate that the oxygen atoms are not equivalent, at least when the ozonide ion is formed according to reaction 2. The geometry of the ion on MgO is believed to be... 

Reactions of 07 with Alkanes and Alkenes. Ozonide ions are intermediate in reactivity between 0 and 01 (20,21). On MgO they re-... 

The formation of similar reaction products when alkanes react with either 0 or 07 suggests that the ozonide ion may first dissociate according to the reverse of reaction 2, and the alkane would then react with the 0 ion. However, the lifetime for the 07 ion under vacuum is considerably longer than the lifetime for the reaction of 07 with an alkane. In addition, each alkane reacts with 07 at a characteristic rate therefore, it seems likely that the alkane reacts directly with 07> rather than indirectly with 0 . 

Alkanes—Continued reactions—Continued with ozonide ions, 135 with superoxide ions, 134-35 role of oxygen ions in oxidation. 138-41 Alkenes, reactions with oxygen ions, 134 with ozonide ions, 135 with superoxide ions, 134-35 Aluminosilicate gels, alkali cations, 241... 

The O3 (ozonide) ion is the only well-established species containing more than two oxygen nuclei. Two types of Oj have been reported and have been characterized mainly by EPR. The evidence for other species is weak and their existence has not been substantiated by direct observation. 

Studies of the thermal stability (334) indicate that OJ ions prepared from 170 and natural oxygen decompose to form OJ, which does not contain 170. On the other hand, most of the OJ ions prepared from, 60 and 170-enriched oxygen decompose to form 02 with significant amounts of 170 with two equivalent oxygen and a hyperfine splitting of 77 G. This evidence indicates that in the Oj ozonide ion, the three oxygen atoms are in different environments as shown by the following model ... 

However, it must be borne in mind that in previous work, H2 did not react with a triangular array of O ions to form OH" ions (354). If such a reaction with H2 occurred, then the O" ions would no longer be available for Oj formation. Moreover, the reaction of pairs of O ions with oxygen should lead to pairs of O J ions which would have an abnormal EPR spectrum if they can be seen at all. In fact, the g tensor is as expected for isolated OJ ions. The CoO-MgO system behaves as CaO for the formation of Oj, i.e., via invisible O ions. The ozonide ions characterized by a three-g-value EPR signal (2.0025, 2.012, 2.017) do not exhibit any superhyperfine interaction with cobalt nuclei, suggesting that they are adsorbed on Mg2+ ions (110). Depending on the system (MgO, CaO, CoO-MgO) and the experimental conditions, the ozonide ion Oj disappears irreversibly between 25° and 130°C. In the case of MgO (333,334), OJ ions are formed when O J ions are destroyed, whereas for CaO (158) and CoO-MgO (110) the evidence is not clear. 

The values of the g tensor for the ozonide ion stabilized on some surfaces are given in Table XII. The consistency of these values for the various systems shows that the g tensor may be used with some confidence to identify the OJ ions. There are, however, a few unusual cases where three oxygen atoms may be involved, but the normal properties of the ozonide ion are not observed. These so-called O3 ions are considered in the next section. 

The ozonide ion O3 has been clearly characterized by EPR and reflectance spectroscopy. Labeling experiments with 170 indicate that the O3 species contains three inequivalent oxygens forming a bond angle of about 110° and that it decomposes slowly at room temperature to form O ". A second type of species has been reported as O3 but has very different characteristics, since it is stable only at low temperatures and labeling experiments with 170, which indicate two equivalent nuclei, are difficult to interpret the balance of the evidence points toward a more complex polyoxygen species (see Section V,A). The data for O4 indicates that it is likely to exist on the surface under special conditions and we expect to see this confirmed by further studies. 

The Ozonide Ion.—The red crystalline substance potassium ozonide, KO3, is obtained by recrystallizing from liquid ammonia the product of reaction of ozone and potassium hydroxide.47 The corresponding ozonides NaO and CsO hasre been shown48 to have magnetic susceptibility corresponding to the presence of the OjT ion with one odd electron. The electronic structure of the ozonide ion is... 

The deep red ozonide ion has a bent structure, and sodium ozonide is isostructural with sodium nitrite (NaNC>2). The X-ray structural data of the alkali metal ozonides show that an increase in cationic size corresponds to a decrease in 0-0 bond length and an increase in 0-0-0 angle, as summarized in the following table ... 

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