Technetium - Tc
| Atomic number | 43 |
|---|---|
| Group / period / block | 7 / 5 / d |
| Relative atomic mass | No standard atomic weight (all isotopes are radioactive) |
| Density at 20 °C | 11 g/cm3 |
| Melting point | 2157 °C |
| Boiling point | 4262 °C |
| Electron configuration | [Kr] 4d5 5s2 |
Technetium
Technetium is a radioactive, silvery metal. Because all its isotopes are unstable, no standard atomic weight is assigned. Technetium-99 is a long-lived fission product; technetium-99m is widely used for medical diagnostic imaging.
Its form in water depends strongly on redox conditions. In oxidizing water, technetium commonly occurs as soluble pertechnetate (TcO4−), which can move readily with groundwater. Under reducing conditions, technetium(IV) can form poorly soluble technetium dioxide (TcO2). This matters for nuclear-fuel-cycle and radioactive-waste monitoring, rather than routine process-water treatment.
Technetium in water treatment
Water-treatment context: Suspected technetium contamination requires radiological characterization and specialist handling. Speciation, redox conditions and co-contaminants affect mobility and separation; ordinary dissolved-metal assumptions do not necessarily apply.
Elemental metals and dissolved metal species behave differently in water. Water chemistry and the exact compound or complex must be considered when assessing treatment.
Back to the periodic table of elements
Sources and further reading
Technetium page last reviewed: by Lenntech.