Binary compounds with halogens (known as halides), oxygen (known as oxides), hydrogen (known as hydrides), and other compounds of astatine where known.
Isolation: astatine is radioactive and essentially unavailable in nature. It is not possible to make other than in a nuclear reactor. Bombardment of the bismuth isotope20983Bi with α-particles (helium nuclei,42He) results in formation of shortlived astatine and neutrons. The bismuth target is cooled during irradiation to prevent the volatile astatine disappearing.
20983Bi +42He →21185At + 210n
The211At isotope has a half life of just over 7 hours so it is necessary to work quickly with it! Available quantities are of the order of 0.001 mg.
Heating the bismuth target to 300-600°C under N2 results in a stream of the elemental astatine that can be collected on a cold glass finger.
Density of solid: 6400 (estimated) kg m-3
Molar volume: 33 (rough estimate based upon density estimate) cm3
Thermal conductivity: 1.7 (estimate) W m‑1 K‑1
Melting point: 575 [302 °C (576 °F)] K
Boiling point: 503 [230 °C (446 °F)] K
Enthalpy of fusion: 20.5 kJ mol-1
Atomic radius (empirical): (no data) pm
Molecular single bond covalent radius: 147 (coordination number 1) ppm
van der Waals radius: [ 288 ] ppm
Pauling electronegativity: 2.2 (Pauling units)
Allred Rochow electronegativity: 1.90 (Pauling units)
Mulliken-Jaffe electronegativity: 2.85 (14.3% s orbital)
First ionisation energy: 899.00 kJ mol‑1
Second ionisation energy: 1725 kJ mol‑1
Third ionisation energy: 2565 kJ mol‑1
Universe: (no data) ppb by weight
Crustal rocks: (no data) ppb by weight
Human: (no data) ppb by weight
