Astatiini

Kemiallinen merkki: At
Järjestysluku: 85
Kategoria: halogeenit
Ryhmä: 17
Jakso: 6
Lohko: p
Moolimassa: (210) g/mol
Elektronia kuorilla: 2, 8, 18, 32, 18, 7
CAS-numero: 7440-68-8
Olomuoto: kiinteä
Tiheys: 4,933 kg/l (lähellä huoneenlämpöä)
Sulamispiste: 575 K (302 °C, 576 °F)
Kiehumispiste: 610 K (337 °C, 639 °F)
Kiderakenne: unknown
Hapetusluvut: 1, 3, 5, 7
Elektronegatiivisuus: 2,2 (Pauling-asteikko)
Nimen alkuperä: astatos
Nimen tarkoitus: a Greek word which means 'unstable' due to its relatively short half-life of about 8 hours
Faktoja:
- is a radioactive element with 33 known isotopes with mass numbers between 191 and 223
- the longest-lived isotope is astatine-210, which has half-life of 8,1 hours; the shortest-lived known isotope is astatine-213, which has a half- life of
- is produced by radioactive decay in nature, due to its short half life it is found only in minute amounts
- the alpha-emitting properties of some astatine isotopes are used for science applications, and also medical applications for astatin
- would be expected to be a nearly black solid, which, when heated, sublimes into a dark, purplish vapor (darker than iodine)
- is the least reactive of the halogens, being less reactive than iodine
- has been proposed with names dakin and helvetium