Xenon tetroxide

Xenontetroxid

As a solid: yellow, slightly exploding crystals

Gaseous

-39.5 ° C

643 kJ / mol

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Xenon (VIII ) oxide is an oxide of the rare gas xenon and thus an inert gas connection. It is a colorless gas under standard conditions.

Production and representation

As a starting material for the production of xenon (VIII ) oxide, solutions of Xenaten in the form HXeO4 -. These can be oxidized by HXeO63 - disproportionation, or by means of ozone to Perxenaten form and precipitated as Bariumperxenat Ba2XeO6. From this one can by means of concentrated sulfuric acid down the unstable intermediate Perxenonsäure H4XeO6 xenon ( VIII ) oxide win:

These reactions are carried out at -5 ° C, whereby the product Xenontetroxid escapes as a gas.

Properties

Xenon ( VIII ) oxide has 643 kJ / mol a positive enthalpy of formation and is thus a highly endothermic compound. This makes it prone to explosive decomposition with formation of elemental xenon and oxygen. In the solid state below -39.5 ° C it exists as a yellowish crystalline mass of much higher stability. Occasionally it may explode even at low temperatures (-40 ° C), which is why the use of Xenontetroxid be done with great caution and must take place at very low temperatures ( liquid nitrogen cooling ). A sudden explosion is triggered when accumulated reaction heat or accumulated (oxygen ) radicals accelerate by gradual disintegration of the further reaction.

Aqueous solution

In aqueous solution, xenon ( VIII ) oxide is in the form of HXeO63 - before ions can be derived from the unstable and not isolable Perxenonsäure H4XeO6. The reason for the instability is the decomposition of Perxenonsäure to xenon acid and oxygen. The decomposition takes place under basic conditions slowly in acids take place very quickly. Stable, however, are a greater number of salts derived from the Perxenonsäure and are called Perxenate. Examples are Ba2XeO6 or Na4XeO6