Praseodymium (Pr)
lanthanideSolid
Standard Atomic Weight
140.90766 uElectron configuration
[Xe] 6s2 4f3Melting point
930.85 °C (1204 K)Boiling point
3519.85 °C (3793 K)Density
6770 kg/m³Oxidation states
0, +1, +2, +3, +4, +5Electronegativity (Pauling)
1.13Ionization energy (1st)
Discovery year
1885Atomic radius
185 pmDetails
Praseodymium is a light lanthanide and one of the rare-earth elements. In nature it occurs with other lanthanides, chiefly in minerals such as monazite and bastnäsite, and only in the +3 oxidation state under normal geochemical conditions. Its chemistry is dominated by Pr³⁺ salts and oxides, but the element is more readily oxidized to Pr⁴⁺ than most neighboring lanthanides. Praseodymium is technologically important in permanent magnets, optical materials, ceramics, and specialized alloys.
Praseodymium is soft, silvery, malleable, and ductile. It is somewhat more resistant to corrosion in air than europium, lanthanum, cerium, or neodymium, but it does develop a green oxide coating that falls off when exposed to air. As with other rare-earth metals, it should be kept under a light mineral oil or sealed in plastic.
The name derives from the Greek prasios for "green" and didymos for "twin" because of the pale green salts it forms. Praseodymium was discovered by the Austrian chemist Carl Auer (Baron von Welsbach) in 1885, who separated it and the element neodymium from a didymium sample (didymium had previously been thought to be a separate element).
Praseodymium was discovered by Carl F. Auer von Welsbach, an Austrian chemist, in 1885. He separated praseodymium, as well as the element neodymium, from a material known as didymium. Today, praseodymium is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements.
From the Greek word prasios, green, and didymos, twin. In 1841 Mosander extracted the rare earth didymia from lanthana; in 1879, Lecoq de Boisbaudran isolated a new earth, samaria, from didymia obtained from the mineral samarskite. Six years later, in 1885, von Welsbach separated didymia into two others, praseodymia and neodymia, which gave salts of different colors. As with other rare earths, compounds of these elements in solution have distinctive sharp spectral absorption bands or lines, some of which are only a few Angstroms wide.
Images
Properties
Physical
Chemical
Thermodynamic
Nuclear
Abundance
Reactivity
N/A
Crystal Structure
Electronic Structure
Identifiers
Electron Configuration Measured
Pr: 4f³ 6s²[Xe] 4f³ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f³ 6s²Atomic model
Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.
Schematic atomic model, not to scale.
Atomic Fingerprint
Emission / Absorption Spectrum
Isotope Distribution
| Mass number | Atomic mass (u) | Natural abundance | Half-life |
|---|---|---|---|
| 141 Stable | 140.9076576 ± 0.0000023 | 100.0000% | Stable |
Phase / State
Reason: 905.9 °C below melting point (930.85 °C)
Schematic, not to scale
Phase transition points
Transition energies
Energy required to melt 1 mol at melting point
Energy required to vaporize 1 mol at boiling point
Energy required to sublime 1 mol at sublimation point
Density
At standard conditions
At standard conditions
Atomic Spectra
Showing 10 of 59 Atomic Spectra. Sorted by ion charge (ascending).
Lines Holdings ?
| Ion | Charge | Total lines | Transition probabilities | Level designations |
|---|---|---|---|---|
| Pr I | 0 | 182 | 0 | 0 |
| Pr II | +1 | 548 | 172 | 356 |
| Pr III | +2 | 372 | 0 | 0 |
| Pr IV | +3 | 135 | 0 | 0 |
| Pr V | +4 | 12 | 0 | 0 |
Levels Holdings ?
| Ion | Charge | Levels |
|---|---|---|
| Pr I | 0 | 430 |
| Pr II | +1 | 201 |
| Pr III | +2 | 430 |
| Pr IV | +3 | 104 |
| Pr V | +4 | 9 |
| Pr VI | +5 | 2 |
| Pr VII | +6 | 2 |
| Pr VIII | +7 | 2 |
| Pr IX | +8 | 2 |
| Pr X | +9 | 2 |
Ionic Radii
| Charge | Coordination | Spin | Radius |
|---|---|---|---|
| +3 | 6 | N/A | 99 pm |
| +3 | 8 | N/A | 112.6 pm |
| +3 | 9 | N/A | 117.9 pm |
| +4 | 6 | N/A | 85 pm |
| +4 | 8 | N/A | 96 pm |
Compounds
Isotopes (1)
| Mass number | Atomic mass (u) | Natural abundance | Half-life | Decay mode | |
|---|---|---|---|---|---|
| 141 Stable | 140.9076576 ± 0.0000023 | 100.0000% | Stable | stable |
Extended Properties
Covalent Radii (Extended)
Van der Waals Radii
Atomic & Metallic Radii
Numbering Scales
Electronegativity Scales
Polarizability & Dispersion
Miedema Parameters
Supply Risk & Economics
Phase Transitions & Allotropes
| Melting point | 1204.15 K |
| Boiling point | 3793.15 K |
Oxidation State Categories
Advanced Reference Data
Screening Constants (13)
| n | Orbital | σ |
|---|---|---|
| 1 | s | 1.1694 |
| 2 | p | 4.2306 |
| 2 | s | 15.538 |
| 3 | d | 13.8476 |
| 3 | p | 19.1756 |
| 3 | s | 19.499 |
| 4 | d | 32.7028 |
| 4 | f | 37.8992 |
| 4 | p | 29.9432 |
| 4 | s | 28.6668 |
Crystal Radii Detail (5)
| Charge | CN | Spin | rcrystal (pm) | Origin |
|---|---|---|---|---|
| 3 | VI | 113 | from r^3 vs V plots, | |
| 3 | VIII | 126.6 | from r^3 vs V plots, | |
| 3 | IX | 131.9 | from r^3 vs V plots, | |
| 4 | VI | 99 | from r^3 vs V plots, | |
| 4 | VIII | 110 | from r^3 vs V plots, |
Isotope Decay Modes (58)
| Isotope | Mode | Intensity |
|---|---|---|
| 121 | p | 100% |
| 122 | B+ | — |
| 122 | B+p | — |
| 123 | B+ | — |
| 123 | B+p | — |
| 124 | B+ | 100% |
| 124 | B+p | — |
| 125 | B+ | 100% |
| 125 | B+p | — |
| 126 | B+ | 100% |
X‑ray Scattering Factors (508)
| Energy (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 1.26325 |
| 10.1617 | — | 1.25455 |
| 10.3261 | — | 1.24591 |
| 10.4931 | — | 1.23732 |
| 10.6628 | — | 1.22879 |
| 10.8353 | — | 1.22033 |
| 11.0106 | — | 1.21192 |
| 11.1886 | — | 1.20357 |
| 11.3696 | — | 1.19528 |
| 11.5535 | — | 1.18704 |
Additional Data
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
9.2 milligrams per kilogram
References (1)
- [5] Praseodymium https://education.jlab.org/itselemental/ele059.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
6.4×10-7 milligrams per liter
References (1)
- [5] Praseodymium https://education.jlab.org/itselemental/ele059.html
Sources
Sources of this element.
The element occurs along with other rare-earth elements in a variety of minerals. Monazite and bastnasite are the two principal commercial sources of the rare-earth metals. It was prepared in relatively pure form in 1931.
References (1)
- [6] Praseodymium https://periodic.lanl.gov/59.shtml
Production
Production of this element (from raw materials or other compounds containing the element).
Ion-exchange and solvent extraction techniques have led to much easier isolation of the rare earths and the cost has dropped greatly in the past few years. Praseodymium can be prepared by several methods, such as by calcium reduction of the anhydrous chloride of fluoride.
References (1)
- [6] Praseodymium https://periodic.lanl.gov/59.shtml
References
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
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This section provides all form of data related to element Praseodymium.
The element property data was retrieved from publications.