Astatine - At

Astatine — chemical properties and water context

Astatine is an extremely rare, radioactive halogen. Only tiny amounts have ever been produced, and its short-lived isotopes mean that many physical properties are estimates rather than routine measured values.

Atomic number	85
Representative isotope mass number	[210] g/mol
Density	Unknown
Melting point	~300 °C (estimated)
Boiling point	~350 °C (estimated)
Electron configuration	[Xe] 4f14 5d10 6s2 6p5

Chemical properties

Astatine is in Group 17 and Period 6. The representative mass number is for astatine-210; it is not a standard atomic weight. Astatine's chemistry resembles that of other halogens, especially iodine, but experiments are constrained by its radioactivity and short half-lives. The RSC lists estimated melting and boiling points and no established density.

Uses and applications

Astatine has no established commercial uses outside research. Some isotopes are studied for targeted radiopharmaceutical research, but their production and handling require specialized radiochemistry and radiation controls.

Astatine and water treatment

Astatine is not a routine water-quality parameter or water-treatment target. There is no general treatment recommendation for astatine in ordinary water systems. Any work involving astatine belongs in a licensed radiochemistry setting with isotope-specific monitoring, containment and waste procedures.

Environmental and health context

Astatine is radioactive and highly scarce; its naturally occurring isotopes are short-lived. Environmental concentrations are not generally managed as routine contaminants. If a specific isotope is involved, use its activity, half-life and radiochemical form in the assessment.

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