Astatine (pronounced as AS-teh-teen) is a non-metal represented by the chemical symbol At, and belongs to the family of halogens . It is not diatomic as it contains only one atom. Among all the members of the halogen group, At shows least reactivity . It has 30 isotopes out of which astatine-210 is the most stable one with a half-life of 8.1 hours .
| Color/appearance | Grayish black |
| Luster | Metallic |
| Odor | Unknown |
| Melting point/freezing point | 300°C (572°F) |
| Boiling point | 350°C (662°F) |
| Density | Unknown |
| State at room temperature (25°C) (solid/liquid/gas) | Solid |
| Hardness | Unknown |
| Electrical conductivity | Unknown |
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