Editing Technetium (section)

===Pertechnetate and other derivatives===
{{main|Pertechnetate}}
[[File:Pertechnetate1.svg|thumb|left|upright|Pertechnetate is one of the most available forms of technetium. It is structurally related to [[permanganate]].]]
The most prevalent form of technetium that is easily accessible is [[sodium pertechnetate]], Na[TcO<sub>4</sub>]. The majority of this material is produced by radioactive decay from [<sup>99</sup>MoO<sub>4</sub>]<sup>2−</sup>:{{sfn|Schwochau|2000|pp=127–136}}<ref name="nuclmed" />

{{block indent|[<sup>99</sup>MoO<sub>4</sub>]<sup>2−</sup>  →   [<sup>99m</sup>TcO<sub>4</sub>]<sup>−</sup>  + e<sup>−</sup>}}

[[Pertechnetate]] ({{chem|TcO|4|-}}) is only weakly hydrated in aqueous solutions,<ref>{{cite journal |last1=Ustynyuk |first1=Yuri A. |last2=Gloriozov |first2=Igor P. |last3=Zhokhova |first3=Nelly I. |last4=German |first4=Konstantin E. |last5=Kalmykov |first5=Stepan N. |date=2021-11-15 |title=Hydration of the pertechnetate anion. DFT study |journal=Journal of Molecular Liquids |volume=342 |page=117404 |doi=10.1016/j.molliq.2021.117404 |issn=0167-7322 |url=https://www.sciencedirect.com/science/article/pii/S0167732221021280 }}</ref> and it behaves analogously to perchlorate anion, both of which are [[tetrahedral molecular geometry|tetrahedral]]. Unlike [[permanganate]] ({{chem|MnO|4|-}}), it is only a weak [[oxidizing agent]].

Related to pertechnetate is [[Technetium(VII) oxide|technetium heptoxide]]. This pale-yellow, volatile solid is produced by oxidation of Tc metal and related precursors:

{{block indent|4 Tc + 7 O<sub>2</sub> → 2 Tc<sub>2</sub>O<sub>7</sub>}}

It is a molecular metal oxide, analogous to [[manganese heptoxide]]. It adopts a [[Centrosymmetry|centrosymmetric]] structure with two types of Tc−O bonds with 167 and 184&nbsp;pm bond lengths.<ref>{{cite journal |last = Krebs |first = B. |date = 1969 |title = Technetium(VII)-oxid: Ein Übergangsmetalloxid mit Molekülstruktur im festen Zustand |language=de |trans-title=Technetium(VII) oxide, a transition metal oxide with a molecular structure in the solid tate |journal = Angewandte Chemie |volume = 81 |issue = 9 |pages = 328–329 |doi = 10.1002/ange.19690810905 | bibcode=1969AngCh..81..328K }}</ref>

Technetium heptoxide hydrolyzes to pertechnetate and [[pertechnetic acid]], depending on the pH:{{sfn|Schwochau|2000|p=127}}<ref>{{cite book |last1=Herrell |first1=A.Y. |last2=Busey |first2=R.H. |last3=Gayer |first3=K.H. |date=1977 |title=Technetium(VII) Oxide, in Inorganic Syntheses |volume=XVII |pages=155–158|isbn=978-0-07-044327-3 }}</ref>

{{block indent|Tc<sub>2</sub>O<sub>7</sub> + 2 OH<sup>−</sup> → 2 TcO<sub>4</sub><sup>−</sup> + H<sub>2</sub>O}}
{{block indent|Tc<sub>2</sub>O<sub>7</sub> + H<sub>2</sub>O  → 2 HTcO<sub>4</sub>}}

HTcO<sub>4</sub> is a strong acid. In concentrated [[sulfuric acid]], [TcO<sub>4</sub>]<sup>−</sup> converts to the octahedral form TcO<sub>3</sub>(OH)(H<sub>2</sub>O)<sub>2</sub>, the conjugate base of the hypothetical tri[[aquo complex]] [TcO<sub>3</sub>(H<sub>2</sub>O)<sub>3</sub>]<sup>+</sup>.<ref>{{cite journal |display-authors=6 |vauthors=Poineau F, Weck PF, German K, Maruk A, Kirakosyan G, Lukens W, Rego DB, Sattelberger AP, KR |name-list-style=vanc |date=2010 |title=Speciation of heptavalent technetium in sulfuric acid: Structural and spectroscopic studies |journal=Dalton Transactions |volume=39 |issue=37 |pmid=20730190 |s2cid=9419843 |pages=8616–8619|doi=10.1039/C0DT00695E |url=http://radchem.nevada.edu/docs/pub/tc%20in%20h2so4%20%28dalton%29%202010-08-23.pdf |access-date=2011-11-14 |url-status=dead |archive-url=https://web.archive.org/web/20170305152213/http://radchem.nevada.edu/docs/pub/tc%20in%20h2so4%20%28dalton%29%202010-08-23.pdf |archive-date=2017-03-05 }}</ref>