Neptunium (Np) VS Plutonium (Pu)
A definitive side-by-side comparison of two essential element profiles.
VS
Main Differences
Neptunium (Np) is an element in the actinoids category with an atomic number of 93. Plutonium (Pu) is an element in the actinoids category with an atomic number of 94.
Neptunium (Np) is 1.0x denser than Plutonium (Pu). Furthermore, Neptunium (Np) melts at a significantly higher temperature than Plutonium (Pu) (a difference of 4.5 Kelvin).
Where do the names come from?
Np Neptunium (Np) Naming History
Neptunium was named after the planet Neptune.
Pu Plutonium (Pu) Naming History
Plutonium, is named after the then planet Pluto, following from the two previous elements uranium and neptunium.
Related Comparisons
Compare
Neptunium (Np)
Plutonium (Pu)
Category
Actinoids
Actinoids
Atomic Number
93
94
Symbol
Np
Pu
Atomic Mass
[237] u
[244] u
Group
Actinides
Actinides
Period
7
7
Block
f-block
f-block
Standard State (at 20°C)
solid
solid
Density
20.45 g/cm³
19.816 g/cm³
Melting Point (°C)
644°C
640°C
Melting Point (°F)
1191°F
1184°F
Melting Point (K)
917 K
912.5 K
Boiling Point (°C)
3902°C
3228°C
Boiling Point (°F)
7056°F
5842°F
Boiling Point (K)
4273 K
3501 K
Year Discovered:
1940
1940
CAS Number
7439-99-8
05/07/7440
Origin of Name:
Neptunium was named after the planet Neptune.
Plutonium, is named after the then planet Pluto, following from the two previous elements uranium and neptunium.