|
Pronunciation | (ASS-tə-teen, -tin) |
---|
Appearance | unknown, probably metallic |
---|
Mass number | [210] |
---|
|
|
Group | group 17 (halogens) |
---|
Period | period 6 |
---|
Block | p-block |
---|
Electron configuration | [Xe] 4f14 5d10 6s2 6p5 |
---|
Electrons per shell | 2, 8, 18, 32, 18, 7 |
---|
|
Phase at STP | solid |
---|
Melting point | 575 K (302 °C, 576 °F) |
---|
Boiling point | 610 K (337 °C, 639 °F) |
---|
Density (near r.t.) | (At2) 6.2–6.5 g/cm3 (predicted)[1] |
---|
Heat of fusion | ca. 6 kJ/mol |
---|
Heat of vaporization | (At2) 54.39 kJ/mol |
---|
Vapor pressure
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
361 |
392 |
429 |
475 |
531 |
607 |
|
|
Oxidation states | −1, +1, +3, +5, +7[2] |
---|
Electronegativity | Pauling scale: 2.2 |
---|
Ionization energies | |
---|
Covalent radius | 150 pm |
---|
Van der Waals radius | 202 pm |
---|
|
Natural occurrence | from decay |
---|
Crystal structure | face-centered cubic (fcc) (predicted)[4] |
---|
Thermal conductivity | 1.7 W/(m⋅K) |
---|
CAS Number | 7440-68-8 |
---|
|
Naming | after Greek: αστατος (astatos), meaning "unstable" |
---|
Discovery | Dale R. Corson, Kenneth Ross MacKenzie, Emilio Segrè (1940) |
---|
|
|
|
|
Category: Astatine | references |