Sodium pertechnetate
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| Names | |
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IUPAC name
Sodium technetate(VII)
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| Other names
sodium tetraoxotechnetate (VII)
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| Identifiers | |
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3D model (Jmol)
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| ECHA InfoCard | 100.033.870 |
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| Properties | |
| NaTcO4 | |
| Molar mass | 169.89 g/mol |
| Appearance | White or pale pink solid |
| Soluble | |
| Related compounds | |
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Other anions
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Sodium permanganate; sodium perrhenate |
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Other cations
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Ammonium pertechnetate |
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Related compounds
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Technetium heptoxide |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is   ?) |
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| Infobox references | |
Sodium pertechnetate is the inorganic compound with the formula NaTcO4. This colourless salt consists of the anion [TcO4]−. The radioactive 99mTcO4− anion is an important radiopharmaceutical for diagnostic use. The advantages to 99mTc include its short half-life of 6 hours and the low radiation exposure to the patient, which allow a patient to be injected with activities of more than 30 millicuries. Na[99mTcO4] is a precursor to a variety of derivatives that are used to image different parts of the body.
[TcO4]− is the starting material for most of the chemistry of technetium. Pertechnetate salts are usually colorless. [TcO4]− is produced by oxidizing technetium with nitric acid or with hydrogen peroxide. The pertechnetate anion is similar to the permanganate anion but is a weaker oxidizing agent. It is tetrahedral and diamagnetic. The standard electrode potential for TcO4−/TcO2 is only +0.738 V in acidic solution, as compared to +1.695 V for MnO4−/MnO2. Because of its diminished oxidizing power, [TcO4]− is stable in alkaline solution. [TcO4]− is more similar to ReO4−. Depending of the reducing agent, [TcO4]− can be converted to derivatives containing Tc(VI), Tc(V), and Tc(IV). In the absence of strong complexing ligands, TcO4− is reduced to a +4 oxidation state via the formation of TcO2 hydrate.
The half-life of 99mTc is long enough that labelling synthesis of the radiopharmaceutical and scintigraphic measurements can be performed without significant loss of radioactivity. The energy emitted from 99mTc is 140 keV, which allows for the study of deep body organs. Radiopharmaceuticals have no intended pharmacologic effect and are used in very low concentrations. Radiopharmaceuticals containing 99mTc are currently being applied in the determining morphology of organs, testing of organ function, and scintigraphic and emission tomographic imaging. The gamma radiation emitted by the radionuclide allows organs to be imaged in vivo tomographically. Currently, over 80% of radiopharmaceuticals used clinically are labelled with 99mTc. A majority of radiopharmaceuticals labelled with 99mTc are synthesized by the reduction of the pertechnetate ion in the presence of ligands chosen to confer organ specificity of the drug. The resulting 99mTc compound is then injected into the body and a "gamma camera" is focused on sections or planes in order to image the spatial distribution of the 99mTc.
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