Pertechnetic acid

Pertechnetic acid

Names
IUPAC name Pertechnetic acid
Identifiers
CAS Number	14332-45-7
3D model (JSmol)	Interactive image
ChemSpider	9979749  Y
PubChem CID	11805084
InChI InChI=1S/H2O.3O.Tc/h1H2;;;;/q;;;;+1/p-1 Y Key: UTQISYNNAQMRBN-UHFFFAOYSA-M Y
SMILES O[Tc](=O)(=O)=O
Properties
Chemical formula	HO4Tc
Molar mass	163 g·mol−1
Conjugate base	Pertechnetate
Related compounds
Other anions	Permanganic acid Perrhenic acid
Other cations	Sodium pertechnetate
Related compounds	Perchloric acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Pertechnetic acid (HTcO₄) is a compound of technetium that is produced by reacting technetium(VII) oxide (Tc₂O₇) with water or reacting Tc metal or TcO2 with strong oxidizing acids, such as nitric acid, mixture of concentrated sulfuric acid with hydrogen peroxide or aqua regia. ^[1] The dark red hygroscopic substance is a strong acid, with a pK_a of 0.32, ^[2] 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 Tc₂₀O4−68, ^[3] while fresh HTcO₄ is white. ^[4]

Use of strong enough acid solution, for example, concentrated sulfuric acid, can generate the protonated form, which then exists as the octahedral TcO₃(OH)(H₂O)₂ dihydrate complex. ^[5]

In aqueous solutions the pertechnic acid is complitely dissociated ^[6] and therefore it is considered as very strong acid its deviation from ideal activity being due to ion pair and triple ion formation with counter-cation of hydronium. ^[7]

Density and activity values of pertechnetic acid aqueous solutions at T = 298.15 K are tabulated in. ^[8]

See also

• Sodium pertechnetate

References

1. Schwochau, Klaus (2000). Technetium : Chemistry and radiopharmaceutical applications. Weinheim [u.a.]: Wiley-VCH. p. 127. ISBN   3-527-29496-1.
2. Omori, T.; Asahina, K.; Suganuma, H. (1995). "Mechanism of the solvent extraction of pertechnetate with tetraphenylarsonium chloride". Journal of Radioanalytical and Nuclear Chemistry. 191 (1): 99–104. doi:10.1007/BF02035989. S2CID   97175462.
3. German, Konstantin E.; Fedoseev, Alexander M.; Grigoriev, Mikhail S.; Kirakosyan, Gayane A.; Dumas, Thomas; Den Auwer, Christophe; Moisy, Philippe; Lawler, Keith V.; Forster, Paul M.; Poineau, Frederic (24 September 2021). "A 70-Year-Old Mystery in Technetium Chemistry Explained by the New Technetium Polyoxometalate [H₇O₃]₄[Tc₂₀O₆₈]⋅4H₂O". Chemistry – A European Journal. 27 (54): 13624–13631. doi:10.1002/chem.202102035.
4. Soderquist, Chuck; Weaver, Jamie; Cho, Herman; McNamara, Bruce; Sinkov, Sergey; McCloy, John (2019-10-21). "Properties of Pertechnic Acid" . Inorganic Chemistry. 58 (20): 14015–14023. doi:10.1021/acs.inorgchem.9b01999. ISSN   0020-1669. OSTI   1749878.
5. Poineau F, Weck PF, German K, Maruk A, Kirakosyan G, Lukens W, Rego DB, Sattelberger AP, Czerwinski KR (2010). "Speciation of heptavalent technetium in sulfuric acid: structural and spectroscopic studies" (PDF). Dalton Transactions. 39 (37): 8616–8619. doi:10.1039/C0DT00695E. PMID   20730190.
6. Ustynyuk, Yuri A.; Gloriozov, Igor P.; Zhokhova, Nelly I.; German, Konstantin E.; Kalmykov, Stepan N. (November 2021). "Hydration of the pertechnetate anion. DFT study" . Journal of Molecular Liquids. 342: 117404. doi:10.1016/j.molliq.2021.117404. ISSN   0167-7322.
7. Volkov, Mikhail A.; Novikov, Anton P.; Grigoriev, Mikhail S.; Kuznetsov, Vitaly V.; Sitanskaia, Anastasiia V.; Belova, Elena V.; Afanasiev, Andrey V.; Nevolin, Iurii M.; German, Konstantin E. (January 2023). "New Preparative Approach to Purer Technetium-99 Samples—Tetramethylammonium Pertechnetate: Deep Understanding and Application of Crystal Structure, Solubility, and Its Conversion to Technetium Zero Valent Matrix". International Journal of Molecular Sciences. 24 (3): 2015. doi: 10.3390/ijms24032015 . ISSN   1422-0067. PMC   9916763 . PMID   36768335.
8. Moeyaert, P.; Abiad, L.; Sorel, C.; Dufrêche, J.-F.; Ruas, A.; Moisy, Ph.; Miguirditchian, M. (December 2015). "Density and activity of pertechnetic acid aqueous solutions at T = 298.15 K" . The Journal of Chemical Thermodynamics. 91: 94–100. doi:10.1016/j.jct.2015.07.006. ISSN   0021-9614.