Perxenates reactions

Oxides. Two oxides of xenon are known xenon trioxide [13776-58-4], XeO, and xenon tetroxide [12340-14-6], XeO (Table 1). Xenon trioxide is most efftcientiy prepared by the hydrolysis of XeE (47) or by the reaction of XeE with HOPOE2 (48). The XeO molecule has a trigonal pyramidal shape Xe—O, 176(3) pm (49), and XeO is tetrahedral with Xe—O, 173.6(2) pm (50). Xenon tetroxide is prepared by the interaction of concentrated sulfuric acid with sodium or barium perxenate, Na XeO, Ba2XeO ( )- Both oxides are thermodynamically unstable, explosive soHds which must be... 

Solid perxenate (Xe064-) salts can be obtained that contain cations of Group IA and IIA metals. The Xe064- ion has a very weak conjugate acid (HXeOe3-) so the hydrolysis reactions... 

Xe03p2 was the first oxyfluoride of octavalent xenon to be prepared. It was made by reaction of XeFe with sodium perxenate solid at room temperature. Xe03p2 is, like Xe04, sufficiently volatile to distil at 195 K. The much greater volatihty of Xe03p2 as compared to Xe02p2 indicates that the molecule of Xe03p2 is more symmetrical and probably nonpolar (Z>3/,). 

CsHXe04 has been prepared by the reaction of xenon trioxide with aqueous cesium hydroxide in the presence of fluoride ion. The role of the fluoride ion in the preparation of CsHXe04 is not clear, but it seems that it prevents the formation of perxenate. In the absence of the fluoride ion, xenon trioxide and cesium hydroxide form a mixed perxenate and xenate salt. CsHXe04 is stable in air. 

Solutions of sodium perxenate are very powerful oxidants, and accidental contact with reducing substances should be avoided. A frequent reaction product is xenon trioxide, the hazards of which are detailed in the preceding s Oithesis. ... 

Determination of the total oxidizing power gives the amount of Xe(VIII) and may best be effected by dissolving the perxenate in a sodium iodide solution, acidifying with dilute perchloric or sulfuric acid, and titrating the liberated triiodide with thiosulfate. The reaction proceeds according to the overall stoichiometry ... 

The amount of base present in the salt (the Na20 content) may be determined by dissolving the perxenate in a measured excess of dilute perchloric or sulfuric acid and back-titrating wdth standard base. The net reaction is ... 

Since the products are perxenate (an Xe(VIII) species) and elemental xenon, this reaction is a disproportionation of the Xe(VI) species HXe04 . Oxygen is produced from a thermodynamically unstable intermediate with Xe(IV), possibly as follows ... 

We will discuss the mechanism of this reaction in the next section. An alternative way of obtaining perxenate involves the oxidation of xenate by ozone in alkaline solution ... 

It is prepared from barium perxenate or sodium perxenate by reaction with anhydrous sulphuric acid. 

XeO is an unstable gas, exploding even at a low temperature. It is prepared by reaction of anhydrous HjSO with barium perxenate or sodium perxenate. 

Identify the reducing and oxidizing agents in the reaction of xenon trioxide with ozone and aqueous sodium hydroxide to produce sodium perxenate as shown in Equation (19.20), repeated below. 

The perxenate-to-xenon standard reduction potential in acid solution is 2.18 V. Write a balanced equation for the oxidation of Cr(III) to dichromate by perxenate in acid solution. Calculate the of this reaction. 

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