Xenic acid

The HP may then be removed by adding MgO to precipitate MgF2 and the colourless deliquescent solid Xe03 obtained by evaporation. The aqueous solution known as xenic acid is quite stable if all oxidizable material is excluded, but the solid is a most dangerous explosive (reported to be comparable to TNT) which is easily detonated. The X-ray analysis, made even more difficult by the tendency of the crystals to disintegrate in an X-ray beam, shows the solid to consist of trigonal pyramidal Xe03 units, with the xenon atom at the apex (cf. the isoelectronic iodate ion 103 p. 863). 

As mentioned above, xenon trioxide is an endothermic compound which explodes violently at the slightest provocation. Aqueous solutions are stable but powerfully oxidizing. These solutions are weakly acidic ( xenic acid ) and contain molecular XeOj When these solutions are made basic. HXeO ions are formed and alkali hydrogen xenates, MHXe04, may be isolated from them. Hydrogen xenale ions disproportionate in alkaline solution to yield perxenates ... 

In a prophetic article written some 30 years ago < > Pauling suggested the existence of XeF, and a less stable XeFg. He also postulated the existence of xenic acid HjXeO, and salts (e.g. Ag XeO,) derivable from this. It was found, at the Atgonne Laboratory that hydrolysis of... 

Preparation by hydrolysis of either xenon tetrafluoride or xenon hexafluoride. Oxidizing action,2 Xenic acid reacts readily with u/c-diols in neutral or alkaline solution the products are xenon (gas) and carboxylic acids. 

Hence, the aqueous hydrolysis of both XeF4 and XeFe results in the formation of the trigonal pyramidal trioxide, XeO-i, in solution. Aqueous solutions of the trioxide, known as xenic acid, are fairly stable and can be used as powerful but kinetically slow oxidizing agents. These might have found wide application were it not for the fact that solid XeOs, which is readily obtained from these solutions on evaporation, is a violent and sensitive explosive. 

Xe03 is typically obtained by hydrolysis of XeFg (as described above) it s soluble in water to quite high concentrations but does at one point crystallize out as colorless, dangerously explosive crystals. In alkaline solution, Xe03 forms the anion of xenic acid ... 

Any remaining perxenic acid decomposes slowly to xenic acid and oxygen ... 

Tellurium-oxygen compounds 66Luzl, 89San Xenic acid 63Reu... 

XeOj dissolves in water to form a weak acid, xenic acid. 

Aqueous solutions of Xe03 are often referred to as ozenic acid. Xenic acid can be oxidized by ozone, for example, to the perxenates as represented in Equation (19.20) ... 

Other xenon halides include the dichloride, the tetrachloride, and the dibromide, but these are not particularly stable. Solutions of xenon trioxide, called xenic acid, are excellent oxidizing agents, as is the octahedral perxenate anion, XeOg. Krypton difluoride, a few nitrogen compounds of both xenon and krypton, and radon difluoride have also been prepared but are not well-characterized. 

The trioxide is the anhydride of xenic acid, H2Xe04. In aqueous basic solution, the acid forms the hydrogen xenate ion, HXe04 , which further disproportionates to the perxenate ion, XeOe", in which xenon attains its highest oxidation number of 4-8. 

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