Praseodymium
lanthanide · period 6 · group 3 · f-block
Praseodymium is a chemical element with the symbol Pr and atomic number 59. It is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals.
What the numbers say
At standard temperature and pressure Praseodymium is a solid, sitting in period 6, group 3 of the f-block.
Its melting point of 1208 K (935 °C) is the 53rd highest of the 110 elements with a measured value — mid-range among the elements.
At 6.64 g/cm³ it is the 53rd densest of 96 elements with a quoted density.
Pauling electronegativity is 1.13. Paired with oxygen (3.44) that is a difference of 2.31, which puts the bond predominantly ionic — expect a stable oxide ceramic.
In the solid state it takes a simple hexagonal structure — hexagonal packing offers few easy slip systems, so properties are anisotropic and formability is limited.
It is reported in 3 oxidation states (2, 3, 4), which sets how many distinct compounds and phases it can form.
First identified in 1885.
Crystal structure
Solid Praseodymium adopts a Simple Hexagonal arrangement, in the Hexagonal system — axes a = b ≠ c, angles α = β = 90°, γ = 120°. Symmetry controls the anisotropy of stiffness and thermal expansion, and the available slip systems set how far the metal deforms before it fractures.
Check it against computed structures
The structure search queries the Materials Project, OQMD and the Open Materials Database for computed crystal structures containing Pr — with DFT formation energy, hull stability and band gap where the provider publishes them.
K 2 · L 8 · M 18 · N 21 · O 8 · P 2
Properties
| Atomic number | 59 |
|---|---|
| Atomic mass | 140.907662 u |
| Series | lanthanide |
| Group | 3 |
| Period | 6 |
| Block | f-block |
| Phase at STP | Solid |
| Density | 6.64 g/cm³ |
| Melting point | 1208 K (935 °C) |
| Boiling point | 3403 K (3130 °C) |
| Electronegativity (Pauling) | 1.13 |
| Electron configuration | [Xe] 4f³ 6s² |
| Crystal structure | Simple Hexagonal |
| Oxidation states | 2,3,4 |
| Discovered | 1885 |
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See Pr in context with all 118 elements.
Working with praseodymium in a real design?
Ask the materials chat how Pr behaves in your alloy system, what it does to weldability, and which grades to look at — with the source of every number named.