Pertechnetic acid (HTcO
4) is a
compound of
technetium that is produced by reacting
technetium(VII) oxide
Technetium(VII) oxide is the chemical compound with the formula Tc2O7. This yellow volatile solid is a rare example of a molecular binary metal oxide, the other examples being RuO4, OsO4, and the unstable Mn2O7. It adopts a centrosymmetric c ...
(Tc
2O
7) with water or strong
oxidizing acids, such as
nitric acid, concentrated
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
or
aqua regia. The dark red
hygroscopic substance is a strong acid, with a
p''K''a of 0.32, as such it exists almost entirely as the
pertechnetate ion in aqueous solution. The red color in solution is thought to be due to the formation of the
polyoxometallate .
Use of strong enough acid solution, for example, concentrated sulfuric acid, can generate the protonated form, which then exists as the octahedral TcO
3(OH)(H
2O)
2 di
hydrate
In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understo ...
complex.
See also
*
Sodium pertechnetate
References
{{Technetium compounds
Pertechnetates
Mineral acids
Transition metal oxoacids