Praseodymium

Praseodymium is a chemical element; it has symbol Pr and atomic number 59. It is the third member of the lanthanide series and is considered one of the rare-earth metals. It is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.

Praseodymium, ₅₉Pr

Praseodymium
Pronunciation	/ˌpreɪziːəˈdɪmiəm/ ​(PRAY-zee-ə-DIM-ee-əm)
Appearance	grayish white
Standard atomic weight Ar°(Pr)
	140.90766±0.00001 140.91±0.01 (abridged)
Praseodymium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson – ↑ Pr ↓ Pa cerium ← praseodymium → neodymium
Atomic number (Z)	59
Group	f-block groups (no number)
Period	period 6
Block	f-block
Electron configuration	[Xe] 4f^3 6s^2
Electrons per shell	2, 8, 18, 21, 8, 2
Physical properties
Phase at STP	solid
Melting point	1204 K ​(931 °C, ​1708 °F)
Boiling point	3403 K ​(3130 °C, ​5666 °F)
Density (at 20° C)	6.773 g/cm^3
when liquid (at m.p.)	6.50 g/cm^3
Heat of fusion	6.89 kJ/mol
Heat of vaporization	331 kJ/mol
Molar heat capacity	27.20 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1771 1973 (2227) (2571) (3054) (3779)
Atomic properties
Oxidation states	common: +3 0, +1, +2, +4,^? +5
Electronegativity	Pauling scale: 1.13
Ionization energies	1st: 527 kJ/mol 2nd: 1020 kJ/mol 3rd: 2086 kJ/mol
Atomic radius	empirical: 182 pm
Covalent radius	203±7 pm
Spectral lines of praseodymium
Other properties
Natural occurrence	primordial
Crystal structure	​double hexagonal close-packed (dhcp) (hP4)
Lattice constants	a = 0.36723 nm c = 1.18328 nm (at 20 °C)
Thermal expansion	4.5×10^−6/K (at 20 °C)
Thermal conductivity	12.5 W/(m⋅K)
Electrical resistivity	poly: 0.700 µΩ⋅m (at r.t.)
Magnetic ordering	paramagnetic
Molar magnetic susceptibility	+5010.0×10^−6 cm^3/mol (293 K)
Young's modulus	37.3 GPa
Shear modulus	14.8 GPa
Bulk modulus	28.8 GPa
Speed of sound thin rod	2280 m/s (at 20 °C)
Poisson ratio	0.281
Vickers hardness	250–745 MPa
Brinell hardness	250–640 MPa
CAS Number	7440-10-0
History
Naming	after Greek πρασιος, "leek green" (for the color of its salts) and δίδυμος, "twin" (of lanthanum)
Discovery	Carl Auer von Welsbach (1885)
Isotopes of praseodymium v e
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct ^141Pr 100% stable ^142Pr synth 19.12 h β^− ^142Nd ε ^142Ce ^143Pr synth 13.57 d β^− ^143Nd
Category: Praseodymium view talk edit | references

Praseodymium always occurs naturally together with the other rare-earth metals. It is the sixth-most abundant rare-earth element and fourth-most abundant lanthanide, making up 9.1 parts per million of the Earth's crust, an abundance similar to that of boron. In 1841, Swedish chemist Carl Gustav Mosander extracted a rare-earth oxide residue he called didymium from a residue he called "lanthana", in turn separated from cerium salts. In 1885, the Austrian chemist Carl Auer von Welsbach separated didymium into two elements that gave salts of different colours, which he named praseodymium and neodymium. The name praseodymium comes from the Ancient Greek πράσινος (prasinos), meaning 'leek-green', and δίδυμος (didymos) 'twin'.

Like most rare-earth elements, praseodymium most readily forms the +3 oxidation state, which is the only stable state in aqueous solution, although the +4 oxidation state is known in some solid compounds and, uniquely among the lanthanides, the +5 oxidation state is attainable at low temperatures. The 0, +1, and +2 oxidation states are rarely found. Aqueous praseodymium ions are yellowish-green, and similarly, praseodymium results in various shades of yellow-green when incorporated into glasses. Many of praseodymium's industrial uses involve its ability to filter yellow light from light sources.

Physical properties

Praseodymium is the third member of the lanthanide series, and a member of the rare-earth metals. In the periodic table, it appears between the lanthanides cerium to its left and neodymium to its right, and above the actinide protactinium. It is a ductile metal with a hardness comparable to that of silver. Praseodymium is calculated to have a very large atomic radius; with a radius of 247 pm, barium, rubidium and caesium are larger. However, observationally, it is usually 185 pm.

Neutral praseodymium's 59 electrons are arranged in the configuration [Xe]4f³6s². Like most other lanthanides, praseodymium usually uses only three electrons as valence electrons, as the remaining 4f electrons are too strongly bound to engage in bonding: this is because the 4f orbitals penetrate the most through the inert xenon core of electrons to the nucleus, followed by 5d and 6s, and this penetration increases with higher ionic charge. Even so, praseodymium can in some compounds lose a fourth valence electron because it is early in the lanthanide series, where the nuclear charge is still low enough and the 4f subshell energy high enough to allow the removal of further valence electrons.

Similarly to the other early lanthanides, praseodymium has a double hexagonal close-packed crystal structure at room temperature, called the alpha phase (α-Pr). At 795 °C (1,068 K) it transforms to a different allotrope that has a body-centered cubic structure (β-Pr), and it melts at 931 °C (1,204 K).

Praseodymium, like all of the lanthanides, is paramagnetic at room temperature. Unlike some other rare-earth metals, which show antiferromagnetic or ferromagnetic ordering at low temperatures, praseodymium is paramagnetic at all temperatures above 1 K.

Chemical properties

Praseodymium(III) hydroxide

Praseodymium metal tarnishes slowly in air, forming a spalling green oxide layer like iron rust; a centimetre-sized sample of praseodymium metal corrodes completely in about a year. It burns readily at 150 °C to form praseodymium(III,IV) oxide, a nonstoichiometric compound approximating to Pr₆O₁₁:

12 Pr + 11 O₂ → 2 Pr₆O₁₁

This may be reduced to praseodymium(III) oxide (Pr₂O₃) with hydrogen gas.Praseodymium(IV) oxide, PrO₂, is the most oxidised product of the combustion of praseodymium and can be obtained by either reaction of praseodymium metal with pure oxygen at 400 °C and 282 bar or by disproportionation of Pr₆O₁₁ in boiling acetic acid. The reactivity of praseodymium conforms to periodic trends, as it is one of the first and thus one of the largest lanthanides. At 1000 °C, many praseodymium oxides with composition PrO_2−x exist as disordered, nonstoichiometric phases with 0 < x < 0.25, but at 400–700 °C the oxide defects are instead ordered, creating phases of the general formula Pr_nO_2n−2 with n = 4, 7, 9, 10, 11, 12, and ∞. These phases PrO_y are sometimes labelled α and β′ (nonstoichiometric), β (y = 1.833), δ (1.818), ε (1.8), ζ (1.778), ι (1.714), θ, and σ.

Praseodymium is an electropositive element and reacts slowly with cold water and quite quickly with hot water to form praseodymium(III) hydroxide:

2 Pr (s) + 6 H₂O (l) → 2 Pr(OH)₃ (aq) + 3 H₂ (g)

Praseodymium metal reacts with all the stable halogens to form trihalides:

2 Pr (s) + 3 F₂ (g) → 2 PrF₃ (s) [green]

2 Pr (s) + 3 Cl₂ (g) → 2 PrCl₃ (s) [green]

2 Pr (s) + 3 Br₂ (g) → 2 PrBr₃ (s) [green]

2 Pr (s) + 3 I₂ (g) → 2 PrI₃ (s)

The tetrafluoride, PrF₄, is also known, and is produced by reacting a mixture of sodium fluoride and praseodymium(III) fluoride with fluorine gas, producing Na₂PrF₆, following which sodium fluoride is removed from the reaction mixture with liquid hydrogen fluoride. Additionally, praseodymium forms a bronze diiodide; like the diiodides of lanthanum, cerium, and gadolinium, it is a praseodymium(III) electride compound.

Praseodymium dissolves readily in dilute sulfuric acid to form solutions containing the chartreuse Pr³⁺ ions, which exist as [Pr(H₂O)₉]³⁺ complexes:

2 Pr (s) + 3 H₂SO₄ (aq) → 2 Pr³⁺ (aq) + 3 SO²⁻
₄ (aq) + 3 H₂ (g)

Dissolving praseodymium(IV) compounds in water does not result in solutions containing the yellow Pr⁴⁺ ions; because of the high positive standard reduction potential of the Pr⁴⁺/Pr³⁺ couple at +3.2 V, these ions are unstable in aqueous solution, oxidising water and being reduced to Pr³⁺. The value for the Pr³⁺/Pr couple is −2.35 V. However, in highly basic aqueous media, Pr⁴⁺ ions can be generated by oxidation with ozone.

Praseodymium(V) has been observed by matrix isolation (in 2016) and in the bulk state (in 2025). The existence of praseodymium in its +5 oxidation state (with the stable electron configuration of the preceding noble gas xenon) under noble-gas matrix isolation conditions was reported in 2016. The species assigned to the +5 state were identified as [PrO₂]⁺, its O₂ and Ar adducts, and PrO₂(η²-O₂). Further, in 2025, a neutral compound [Pr(NP^tBu₃)₄]⁺[PF₆]^–, formally Pr(V) but with an inverted ligand field, was isolated and characterized crystallographically at low temperatures.

Organopraseodymium compounds

Organopraseodymium compounds are very similar to those of the other lanthanides, as they all share an inability to undergo π backbonding. They are thus mostly restricted to the mostly ionic cyclopentadienides (isostructural with those of lanthanum) and the σ-bonded simple alkyls and aryls, some of which may be polymeric. The coordination chemistry of praseodymium is largely that of the large, electropositive Pr³⁺ ion, and is thus largely similar to those of the other early lanthanides La³⁺, Ce³⁺, and Nd³⁺. For instance, like lanthanum, cerium, and neodymium, praseodymium nitrates form both 4:3 and 1:1 complexes with 18-crown-6, whereas the middle lanthanides from promethium to gadolinium can only form the 4:3 complex and the later lanthanides from terbium to lutetium cannot successfully coordinate to all the ligands. Such praseodymium complexes have high but uncertain coordination numbers and poorly defined stereochemistry, with exceptions resulting from exceptionally bulky ligands such as the tricoordinate [Pr{N(SiMe₃)₂}₃]. There are also a few mixed oxides and fluorides involving praseodymium(IV), but it does not have an appreciable coordination chemistry in this oxidation state like its neighbour cerium. However, the first example of a molecular complex of praseodymium(IV) has recently been reported.

Isotopes

Praseodymium has only one stable and naturally occurring isotope, ¹⁴¹Pr. It is thus a mononuclidic and monoisotopic element, and its standard atomic weight can be determined with high precision as it is a constant of nature. This isotope has 82 neutrons, which is a magic number that confers additional stability. This isotope is produced in stars through the s- and r-processes (slow and rapid neutron capture, respectively). Thirty-eight other radioisotopes have been synthesized. All of these isotopes have half-lives under a day (and most under a minute), with the single exception of ¹⁴³Pr with a half-life of 13.6 days. Both ¹⁴³Pr and ¹⁴¹Pr occur as fission products of uranium. The primary decay mode of isotopes lighter than ¹⁴¹Pr is positron emission or electron capture to isotopes of cerium, while that of heavier isotopes is beta decay to isotopes of neodymium.

History

Carl Auer von Welsbach (1858–1929), discoverer of praseodymium in 1885.

In 1751, the Swedish mineralogist Axel Fredrik Cronstedt discovered a heavy mineral from the mine at Bastnäs, later named cerite. Thirty years later, the fifteen-year-old Wilhelm Hisinger, from the family owning the mine, sent a sample of it to Carl Scheele, who did not find any new elements within. In 1803, after Hisinger had become an ironmaster, he returned to the mineral with Jöns Jacob Berzelius and isolated a new oxide, which they named ceria after the dwarf planet Ceres, which had been discovered two years earlier. Ceria was simultaneously and independently isolated in Germany by Martin Heinrich Klaproth. Between 1839 and 1843, ceria was shown to be a mixture of oxides by the Swedish surgeon and chemist Carl Gustaf Mosander, who lived in the same house as Berzelius; he separated out two other oxides, which he named lanthana and didymia. He partially decomposed a sample of cerium nitrate by roasting it in air and then treating the resulting oxide with dilute nitric acid. The metals that formed these oxides were thus named lanthanum and didymium.

While lanthanum turned out to be a pure element, didymium was not and turned out to be only a mixture of all the stable early lanthanides from praseodymium to europium, as had been suspected by Marc Delafontaine after spectroscopic analysis, though he lacked the time to pursue its separation into its constituents. The heavy pair of samarium and europium were only removed in 1879 by Paul-Émile Lecoq de Boisbaudran and it was not until 1885 that Carl Auer von Welsbach separated didymium into praseodymium and neodymium. Von Welsbach confirmed the separation by spectroscopic analysis, but the products were of relatively low purity. Since neodymium was a larger constituent of didymium than praseodymium, it kept the old name with disambiguation, while praseodymium was distinguished by the leek-green colour of its salts (Greek πρασιος, "leek green"). The composite nature of didymium had previously been suggested in 1882 by Bohuslav Brauner, who did not experimentally pursue its separation.

Occurrence and production

Praseodymium is not particularly rare, despite it being in the rare-earth metals, making up 9.2 mg/kg of the Earth's crust. Praseodymium's classification as a rare-earth metal comes from its rarity relative to "common earths" such as lime and magnesia, the few known minerals containing it for which extraction is commercially viable, as well as the length and complexity of extraction. Although not particularly rare, praseodymium is never found as a dominant rare earth in praseodymium-bearing minerals. It is always preceded by cerium and lanthanum and usually also by neodymium.

The Pr³⁺ ion is similar in size to the early lanthanides of the cerium group (those from lanthanum up to samarium and europium) that immediately follow in the periodic table, and hence it tends to occur along with them in phosphate, silicate and carbonate minerals, such as monazite (M^IIIPO₄) and bastnäsite (M^IIICO₃F), where M refers to all the rare-earth metals except scandium and the radioactive promethium (mostly Ce, La, and Y, with somewhat less Nd and Pr). Bastnäsite is usually lacking in thorium and the heavy lanthanides, and the purification of the light lanthanides from it is less involved. The ore, after being crushed and ground, is first treated with hot concentrated sulfuric acid, evolving carbon dioxide, hydrogen fluoride, and silicon tetrafluoride. The product is then dried and leached with water, leaving the early lanthanide ions, including lanthanum, in solution.

The procedure for monazite, which usually contains all the rare earth, as well as thorium, is more involved. Monazite, because of its magnetic properties, can be separated by repeated electromagnetic separation. After separation, it is treated with hot concentrated sulfuric acid to produce water-soluble sulfates of rare earth. The acidic filtrates are partially neutralized with sodium hydroxide to pH 3–4, during which thorium precipitates as hydroxide and is removed. The solution is treated with ammonium oxalate to convert rare earth to their insoluble oxalates, the oxalates are converted to oxides by annealing, and the oxides are dissolved in nitric acid. This last step excludes one of the main components, cerium, whose oxide is insoluble in HNO₃. Care must be taken when handling some of the residues as they contain ²²⁸Ra, the daughter of ²³²Th, which is a strong gamma emitter.

Praseodymium may then be separated from the other lanthanides via ion-exchange chromatography, or by using a solvent such as tributyl phosphate where the solubility of Ln³⁺ increases as the atomic number increases. If ion-exchange chromatography is used, the mixture of lanthanides is loaded into one column of cation-exchange resin and Cu²⁺ or Zn²⁺ or Fe³⁺ is loaded into the other. An aqueous solution of a complexing agent, known as the eluant (usually triammonium edtate), is passed through the columns, and Ln³⁺ is displaced from the first column and redeposited in a compact band at the top of the column before being re-displaced by NH⁺
₄. The Gibbs free energy of formation for Ln(edta·H) complexes increases along with the lanthanides by about one quarter from Ce³⁺ to Lu³⁺, so that the Ln³⁺ cations descend the development column in a band and are fractionated repeatedly, eluting from heaviest to lightest. They are then precipitated as their insoluble oxalates, burned to form the oxides, and then reduced to metals.

Applications

Leo Moser (not to be confused with the mathematician of the same name), son of Ludwig Moser, founder of the Moser Glassworks in what is now Karlovy Vary in the Czech Republic, investigated the use of praseodymium in glass coloration in the late 1920s, yielding a yellow-green glass given the name "Prasemit". However, at that time far cheaper colorants could give a similar color, so Prasemit was not popular, few pieces were made, and examples are now extremely rare. Moser also blended praseodymium with neodymium to produce "Heliolite" glass ("Heliolit" in German), which was more widely accepted. The first enduring commercial use of purified praseodymium, which continues today, is in the form of a yellow-orange "Praseodymium Yellow" stain for ceramics, which is a solid solution in the zircon lattice. This stain has no hint of green in it; by contrast, at sufficiently high loadings, praseodymium glass is distinctly green rather than pure yellow.

Like many other lanthanides, praseodymium's shielded f-orbitals allow for long excited state lifetimes and high luminescence yields. Pr³⁺ as a dopant ion therefore sees many applications in optics and photonics. These include DPSS-lasers, single-mode fiber optical amplifiers, fiber lasers,upconverting nanoparticles as well as activators in red, green, blue, and ultraviolet phosphors. Silicate crystals doped with praseodymium ions have also been used to slow a light pulse down to a few hundred meters per second.

As the lanthanides are so similar, praseodymium can substitute for most other lanthanides without significant loss of function, and indeed many applications such as mischmetal and ferrocerium alloys involve variable mixes of several lanthanides, including small quantities of praseodymium. The following more modern applications involve praseodymium specifically or at least praseodymium in a small subset of the lanthanides:

• In combination with neodymium, another rare-earth element, praseodymium is used to create high-power magnets notable for their strength and durability. In general, most alloys of the cerium-group rare earths (lanthanum through samarium) with 3d transition metals give extremely stable magnets that are often used in small equipment, such as motors, printers, watches, headphones, loudspeakers, and magnetic storage.
• Praseodymium–nickel intermetallic (PrNi₅) has such a strong magnetocaloric effect that it has allowed scientists to approach within one thousandth of a degree of absolute zero.
• As an alloying agent with magnesium to create high-strength metals that are used in aircraft engines; yttrium and neodymium are suitable substitutes.
• Praseodymium is present in the rare-earth mixture whose fluoride forms the core of carbon arc lights, which are used in the motion picture industry for studio lighting and projector lights.
• Praseodymium compounds give glasses, enamels and ceramics a yellow color.
• Praseodymium is a component of didymium glass, which is used to make certain types of welder's and glass blower's goggles.
• Praseodymium oxide in solid solution with ceria or ceria-zirconia has been used as an oxidation catalyst.

Due to its role in permanent magnets used for wind turbines, it has been argued that praseodymium will be one of the main objects of geopolitical competition in a world running on renewable energy. However, this perspective has been criticized for failing to recognize that most wind turbines do not use permanent magnets and for underestimating the power of economic incentives for expanded production.

Praseodymium

Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H250
Precautionary statements	P222, P231, P422
NFPA 704 (fire diamond)	0 4 4

Biological role and precautions

The early lanthanides have been found to be essential to some methanotrophic bacteria living in volcanic mudpots, such as Methylacidiphilum fumariolicum: lanthanum, cerium, praseodymium, and neodymium are about equally effective. Praseodymium is otherwise not known to have a biological role in any other organisms, but it is not very toxic either. Intravenous injection of rare earths into animals has been known to impair liver function, but the main side effects from inhalation of rare-earth oxides in humans come from radioactive thorium and uranium impurities.

Notes

1. The thermal expansion is highly anisotropic: the parameters (at 20 °C) for each crystal axis are α_a = 1.4×10⁻⁶/K, α_c = 10.8×10⁻⁶/K, and α_average = α_V/3 = 4.5×10⁻⁶/K.

References

1. "praseodymium". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
2. "Standard Atomic Weights: Praseodymium". CIAAW. 2017.
3. Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (4 May 2022). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
4. Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
5. Yttrium and all lanthanides except Ce and Pm have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev. 22: 17–24. doi:10.1039/CS9932200017. and Arnold, Polly L.; Petrukhina, Marina A.; Bochenkov, Vladimir E.; Shabatina, Tatyana I.; Zagorskii, Vyacheslav V.; Cloke (15 December 2003). "Arene complexation of Sm, Eu, Tm and Yb atoms: a variable temperature spectroscopic investigation". Journal of Organometallic Chemistry. 688 (1–2): 49–55. doi:10.1016/j.jorganchem.2003.08.028.
6. Chen, Xin; et al. (13 December 2019). "Lanthanides with Unusually Low Oxidation States in the PrB₃^– and PrB₄^– Boride Clusters". Inorganic Chemistry. 58 (1): 411–418. doi:10.1021/acs.inorgchem.8b02572. PMID 30543295. S2CID 56148031.
7. All the lanthanides, except Pm, in the +2 oxidation state have been observed in organometallic molecular complexes, see Lanthanides Topple Assumptions and Meyer, G. (2014). "All the Lanthanides Do It and Even Uranium Does Oxidation State +2". Angewandte Chemie International Edition. 53 (14): 3550–51. doi:10.1002/anie.201311325. PMID 24616202.. Additionally, all the lanthanides (La–Lu) form dihydrides (LnH₂), dicarbides (LnC₂), monosulfides (LnS), monoselenides (LnSe), and monotellurides (LnTe), but for most elements these compounds have Ln³⁺ ions with electrons delocalized into conduction bands, e. g. Ln³⁺(H⁻)₂(e⁻).
8. Jackson, M. (2000). "Magnetism of Rare Earth" (PDF). The IRM quarterly. 10 (3): 1.
9. Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
10. Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
11. Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton, Florida: CRC Press. ISBN 0-8493-0486-5.
12. Clementi, E.; Raimond, D. L.; Reinhardt, W. P. (1967). "Atomic Screening Constants from SCF Functions. II. Atoms with 37 to 86 Electrons". Journal of Chemical Physics. 47 (4): 1300–1307. Bibcode:1967JChPh..47.1300C. doi:10.1063/1.1712084.
13. Slater, J. C. (1964). "Atomic Radii in Crystals". Journal of Chemical Physics. 41 (10): 3199–3205. Bibcode:1964JChPh..41.3199S. doi:10.1063/1.1725697.
14. Greenwood and Earnshaw, pp. 1232–8
15. Cullity, B. D.; Graham, C. D. (2011). Introduction to Magnetic Materials. John Wiley & Sons. ISBN 978-1-118-21149-6.
16. "Rare-Earth Metal Long Term Air Exposure Test". Retrieved 8 August 2009.
17. "Chemical reactions of Praseodymium". Webelements. Retrieved 9 July 2016.
18. Greenwood and Earnshaw, pp. 1238–9
19. Brauer, G.; Pfeiffer, B. (1963). "Hydrolytische spaltung von höheren oxiden des Praseodyms und des terbiums". Journal of the Less Common Metals. 5 (2): 171–176. doi:10.1016/0022-5088(63)90010-9.
20. Minasian, S.G.; Batista, E.R.; Booth, C.H.; Clark, D.L.; Keith, J.M.; Kozimor, S.A.; Lukens, W.W.; Martin, R.L.; Shuh, D.K.; Stieber, C.E.; Tylisczcak, T.; Wen, Xiao-dong (2017). "Quantitative Evidence for Lanthanide-Oxygen Orbital Mixing in CeO2, PrO2, and TbO2" (PDF). Journal of the American Chemical Society. 139 (49): 18052–18064. Bibcode:2017JAChS.13918052M. doi:10.1021/jacs.7b10361. OSTI 1485070. PMID 29182343. S2CID 5382130.
21. Greenwood and Earnshaw, pp. 643–4
22. Greenwood and Earnshaw, p. 1240–2
23. Greenwood and Earnshaw, pp. 1242–4
24. Sroor, Farid M.A.; Edelmann, Frank T. (2012). "Lanthanides: Tetravalent Inorganic". Encyclopedia of Inorganic and Bioinorganic Chemistry. doi:10.1002/9781119951438.eibc2033. ISBN 978-1-119-95143-8.
25. Greenwood and Earnshaw, pp. 1232–5
26. Hobart, D.E.; Samhoun, K.; Young, J.P.; Norvell, V.E.; Mamantov, G.; Peterson, J. R. (1980). "Stabilization of Praseodymium(IV) and Terbium(IV) in Aqueous Carbonate Solution". Inorganic and Nuclear Chemistry Letters. 16 (5): 321–328. doi:10.1016/0020-1650(80)80069-9.
27. Zhang, Qingnan; Hu, Shu-Xian; Qu, Hui; Su, Jing; Wang, Guanjun; Lu, Jun-Bo; Chen, Mohua; Zhou, Mingfei; Li, Jun (6 June 2016). "Pentavalent Lanthanide Compounds: Formation and Characterization of Praseodymium(V) Oxides". Angewandte Chemie International Edition. 55 (24): 6896–6900. doi:10.1002/anie.201602196. ISSN 1521-3773. PMID 27100273.
28. Andrew C. Boggiano; Chad M. Studvick; Sabyasachi Roy Chowdhury; Julie E. Niklas; Haruko Tateyama; Hongwei Wu; Johannes E. Leisen; Florian Kleemiss; Bess Vlaisavljevich; Ivan A. Popov; Henry S. La Pierre (2025). "Praseodymium in the formal +5 oxidation state". Nature Chemistry. doi:10.1038/s41557-025-01797-w.
29. Greenwood and Earnshaw, pp. 1248–9
30. Greenwood and Earnshaw, pp. 1244–8
31. Willauer, A.R.; Palumbo, C.T.; Fadaei-Tirani, F.; Zivkovic, I.; Douair, I.; Maron, L.; Mazzanti, M. (2020). "Accessing the +IV Oxidation State in Molecular Complexes of Praseodymium". Journal of the American Chemical Society. 142 (12): 489–493. Bibcode:2020JAChS.142.5538W. doi:10.1021/jacs.0c01204. PMID 32134644. S2CID 212564931.
32. Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
33. Cameron, A. G. W. (1973). "Abundance of the Elements in the Solar System" (PDF). Space Science Reviews. 15 (1): 121–146. Bibcode:1973SSRv...15..121C. doi:10.1007/BF00172440. S2CID 120201972. Archived from the original (PDF) on 21 October 2011.
34. Emsley, pp. 120–5
35. Greenwood and Earnshaw, p. 1424
36. Weeks, Mary Elvira (1932). "The Discovery of the Elements: XI. Some Elements Isolated with the Aid of Potassium and Sodium:Zirconium, Titanium, Cerium and Thorium". The Journal of Chemical Education. 9 (7): 1231–1243. Bibcode:1932JChEd...9.1231W. doi:10.1021/ed009p1231.
37. Weeks, Mary Elvira (1956). The discovery of the elements (6th ed.). Easton, PA: Journal of Chemical Education.
38. Marshall, James L.; Marshall, Virginia R. (Winter 2015). "Rediscovery of the elements: The Rare Earths – The Confusing Years" (PDF). The Hexagon: 72–77.
39. (Berzelius) (1839) "Nouveau métal" (New metal), Comptes rendus, 8 : 356–357. From p. 356: "L'oxide de cérium, extrait de la cérite par la procédé ordinaire, contient à peu près les deux cinquièmes de son poids de l'oxide du nouveau métal qui ne change que peu les propriétés du cérium, et qui s'y tient pour ainsi dire caché. Cette raison a engagé M. Mosander à donner au nouveau métal le nom de Lantane." (The oxide of cerium, extracted from cerite by the usual procedure, contains almost two fifths of its weight in the oxide of the new metal, which differs only slightly from the properties of cerium, and which is held in it so to speak "hidden". This reason motivated Mr. Mosander to give to the new metal the name Lantane.)
40. (Berzelius) (1839) "Latanium — a new metal," Philosophical Magazine, new series, 14 : 390–391.
41. Fontani, Marco; Costa, Mariagrazia; Orna, Virginia (2014). The Lost Elements: The Periodic Table's Shadow Side. Oxford University Press. pp. 122–123. ISBN 978-0-19-938334-4.
42. Greenwood and Earnshaw, p. 1229–32
43. Fontani, Marco; Costa, Mariagrazia; Orna, Virginia (2014). The Lost Elements: The Periodic Table's Shadow Side. Oxford University Press. p. 40. ISBN 978-0-19-938334-4.
44. Abundance of Elements in the Earth's Crust and in the Sea, CRC Handbook of Chemistry and Physics, 97th edition (2016–2017), p. 14-17
45. Patnaik, Pradyot (2003). Handbook of Inorganic Chemical Compounds. McGraw-Hill. pp. 444–446. ISBN 978-0-07-049439-8. Retrieved 6 June 2009.
46. Hudson Institute of Mineralogy (1993–2018). "Mindat.org". www.mindat.org. Retrieved 14 January 2018.
47. Patnaik 2007, pp. 478–479 harvnb error: no target: CITEREFPatnaik2007 (help).
48. Kreidl, Norbert J. (1942). "RARE EARTHS*". Journal of the American Ceramic Society. 25 (5): 141–143. doi:10.1111/j.1151-2916.1942.tb14363.x.
49. Jha, A.; Naftaly, M.; Jordery, S.; Samson, B. N.; et al. (1995). "Design and fabrication of Pr3+-doped fluoride glass optical fibres for efficient 1.3 mu m amplifiers" (PDF). Pure and Applied Optics: Journal of the European Optical Society Part A. 4 (4): 417. Bibcode:1995PApOp...4..417J. doi:10.1088/0963-9659/4/4/019.
50. Smart, R.G.; Hanna, D.C.; Tropper, A.C.; Davey, S.T.; Carter, S.F.; Szebesta, D. (1991). "Cw room temperature upconversion lasing at blue, green and red wavelengths in infrared-pumped Pr3+-doped fluoride fibre". Electronics Letters. 27 (14): 1307. Bibcode:1991ElL....27.1307S. doi:10.1049/el:19910817.
51. de Prinse, Thomas J.; Karami, Afshin; Moffatt, Jillian E.; Payten, Thomas B.; Tsiminis, Georgios; Teixeira, Lewis Da Silva; Bi, Jingxiu; Kee, Tak W.; Klantsataya, Elizaveta; Sumby, Christopher J.; Spooner, Nigel A. (2021). "Dual Laser Study of Non-Degenerate Two Wavelength Upconversion Demonstrated in Sensitizer-Free NaYF 4 :Pr Nanoparticles". Advanced Optical Materials. 9 (7): 2001903. doi:10.1002/adom.202001903. hdl:2440/139814. ISSN 2195-1071. S2CID 234059121.
52. Kolesov, Roman; Reuter, Rolf; Xia, Kangwei; Stöhr, Rainer; Zappe, Andrea; Wrachtrup, Jörg (31 October 2011). "Super-resolution upconversion microscopy of praseodymium-doped yttrium aluminum garnet nanoparticles". Physical Review B. 84 (15): 153413. Bibcode:2011PhRvB..84o3413K. doi:10.1103/PhysRevB.84.153413. ISSN 1098-0121.
53. McGill, Ian. "Rare Earth Elements". Ullmann's Encyclopedia of Industrial Chemistry. Vol. 31. Weinheim: Wiley-VCH. p. 183–227. doi:10.1002/14356007.a22_607. ISBN 978-3-527-30673-2.
54. "ANU team stops light in quantum leap". Retrieved 18 May 2009.
55. Rare Earth Elements 101 Archived 2013-11-22 at the Wayback Machine, IAMGOLD Corporation, April 2012, pp. 5, 7.
56. Emsley, pp. 423–5
57. Rokhlin, L. L. (2003). Magnesium alloys containing rare earth metals: structure and properties. CRC Press. ISBN 978-0-415-28414-1.
58. Suseelan Nair, K.; Mittal, M. C. (1988). "Rare Earths in Magnesium Alloys". Materials Science Forum. 30: 89–104. doi:10.4028/www.scientific.net/MSF.30.89. S2CID 136992837.
59. Borchert, Y.; Sonstrom, P.; Wilhelm, M.; Borchert, H.; et al. (2008). "Nanostructured Praseodymium Oxide: Preparation, Structure, and Catalytic Properties". Journal of Physical Chemistry C. 112 (8): 3054. doi:10.1021/jp0768524.
60. Overland, Indra (1 March 2019). "The geopolitics of renewable energy: Debunking four emerging myths". Energy Research & Social Science. 49: 36–40. Bibcode:2019ERSS...49...36O. doi:10.1016/j.erss.2018.10.018. hdl:11250/2579292. ISSN 2214-6296.
61. Klinger, Julie Michelle (2017). Rare earth frontiers : from terrestrial subsoils to lunar landscapes. Ithaca, NY: Cornell University Press. ISBN 978-1501714603. JSTOR 10.7591/j.ctt1w0dd6d.
62. "Praseodymium 261173".
63. Pol, Arjan; Barends, Thomas R. M.; Dietl, Andreas; Khadem, Ahmad F.; Eygensteyn, Jelle; Jetten, Mike S. M.; Op Den Camp, Huub J. M. (2013). "Rare earth metals are essential for methanotrophic life in volcanic mudpots" (PDF). Environmental Microbiology. 16 (1): 255–64. Bibcode:2014EnvMi..16..255P. doi:10.1111/1462-2920.12249. PMID 24034209.
64. Kang, L.; Shen, Z.; Jin, C. (2000). "Neodymium cations Nd³⁺ were transported to the interior of Euglena gracilis". Chin. Sci. Bull. 45 (277): 585–592. Bibcode:2000ChSBu..45..585K. doi:10.1007/BF02886032. S2CID 95983365.

Bibliography

• Emsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements. Oxford University Press. ISBN 978-0-19-960563-7.
• Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.

Further reading

• R. J. Callow, The Industrial Chemistry of the Lanthanons, Yttrium, Thorium, and Uranium, Pergamon Press, 1967.
• Bouhani, H.; Endichi, A.; Kumar, D.; Copie, O.; Zaari, H.; David, A.; Fouchet, A.; Prellier, W.; Mounkachi, O.; Balli, M.; Benyoussef, A.; El Kenz, A.; Mangin, S. (17 August 2020). "Engineering the magnetocaloric properties of PrVO3 epitaxial oxide thin films by strain effects". Applied Physics Letters. 117 (7). arXiv:2008.09193. doi:10.1063/5.0021031.

External links

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Look up praseodymium in Wiktionary, the free dictionary.

• WebElements.com—Praseodymium
• It's Elemental—The Element Praseodymium