Uranium (U) VS Neptunium (Np)
A definitive side-by-side comparison of two essential element profiles.
VS
Main Differences
Uranium (U) is an element in the actinoids category with an atomic number of 92. Neptunium (Np) is an element in the actinoids category with an atomic number of 93.
Neptunium (Np) is 1.1x denser than Uranium (U). Furthermore, Uranium (U) melts at a significantly higher temperature than Neptunium (Np) (a difference of 488.3 Kelvin).
Where do the names come from?
U Uranium (U) Naming History
Uranium was named after the planet Uranus.
Np Neptunium (Np) Naming History
Neptunium was named after the planet Neptune.
Related Comparisons
Compare
Uranium (U)
Neptunium (Np)
Category
Actinoids
Actinoids
Atomic Number
92
93
Symbol
U
Np
Atomic Mass
238.029 u
[237] u
Group
Actinides
Actinides
Period
7
7
Block
f-block
f-block
Standard State (at 20°C)
solid
solid
Density
19.1 g/cm³
20.45 g/cm³
Melting Point (°C)
1135°C
644°C
Melting Point (°F)
2075°F
1191°F
Melting Point (K)
1405.3 K
917 K
Boiling Point (°C)
4131°C
3902°C
Boiling Point (°F)
7468°F
7056°F
Boiling Point (K)
4404 K
4273 K
Year Discovered:
1789
1940
CAS Number
7440-61-1
7439-99-8
Origin of Name:
Uranium was named after the planet Uranus.
Neptunium was named after the planet Neptune.