Polonium (Po) VS Astatine (At)
A definitive side-by-side comparison of two essential element profiles.
VS
Main Differences
Polonium (Po) is an element in the post-transition metals category with an atomic number of 84. Astatine (At) is an element in the halogens category with an atomic number of 85.
Polonium (Po) is 1.3x denser than Astatine (At). However, Astatine (At) melts at a higher temperature than Polonium (Po) (a difference of 48.0 Kelvin).
Where do the names come from?
Po Polonium (Po) Naming History
Polonium is named after Poland, the native country of Marie Curie, who first isolated the element.
At Astatine (At) Naming History
The name Astatine comes from the Greek ''astatos'', meaning unstable.
Related Comparisons
Compare
Polonium (Po)
Astatine (At)
Category
Post-transition Metals
Halogens
Atomic Number
84
85
Symbol
Po
At
Atomic Mass
[209] u
[210] u
Group
16
17
Period
6
6
Block
p-block
p-block
Standard State (at 20°C)
solid
solid
Density
9.2 g/cm³
7.0* g/cm³
Melting Point (°C)
254°C
300°C
Melting Point (°F)
489°F
572°F
Melting Point (K)
527 K
575 K
Boiling Point (°C)
962°C
350°C
Boiling Point (°F)
1764°F
662°F
Boiling Point (K)
1235 K
610 K
Year Discovered:
1898
1940
CAS Number
06/08/7440
7440-68-8
Origin of Name:
Polonium is named after Poland, the native country of Marie Curie, who first isolated the element.
The name comes from the Greek ''astatos'', meaning unstable.