What Is Praseodymium Definition Electron Configuration Oxidation States and Uses
What is Praseodymium?
Praseodymium is a chemical element which is the 3rd member of the Lanthanide series and is placed in the 6th period. Symbol of the praseodymium element is Pr. It is a metal which is traditionally considered to be one of the rare earth metals. Its atomic number 59. Protactinium which is a member of actinide series is placed below praseodymium in the periodic table. Another metal cerium is found at the left of praseodymium and neodymium is present at the right in the 6th period of the periodic table. Cerium and neodymium metals are also members of the Lanthanide series. Praseodymium is a member of the f – block element. It is the 4th most common rare earth metal. It is found in earth’s crust and forms 9.1 parts per million of the earth’s crust. It is similar to boron in abundance in the earth’s crust.
Praseodymium was discovered by Austrian Chemist Baron Carl Auer von Welsbach in 1885. Swedish chemist Carl Gustav Mosander extracted didymium (a rare earth oxide) from lanthana in 1841. Baron Carl Auer von Welsbach separated didymium into elements and these two elements were different from each other. One was praseodymium and another one was neodymium. Thus, discovery of praseodymium took place. The word praseodymium is derived from the Greek word ‘prasinos’ which means green colored and ‘didymos’ which means twin. Praseodymium is not found in pure elemental form in nature as it is a reactive metal and generally forms a green coating of its oxide when exposed to moist air. It is a soft, ductile, malleable and silvery colored metal.
It is a monoisotopic element as it has only one natural isotope which is 141Pr. It is stable in nature. Although it has other synthetic isotopes. Out of synthetic isotopes of praseodymium 142Pr and 143Pr are most stable isotopes with a half - life period of 19.12 hours and 13.57 days respectively.
Praseodymium Atomic Number and Electronic Configuration
Atomic number of Praseodymium is 59. Its electronic configuration is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f3 5d0 6s2 or it can be written as [Xe] 4f3 6s2. It has 2 electrons in K – shell, 8 electrons in L – shell, 18 electrons in M – shell and 21 electrons in its outermost shell N, 8 electrons in O shell and 2 electrons in P shell.
Properties of Praseodymium
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Physical and Chemical Properties - Physical and chemical properties of Praseodymium are listed below –
Its atomic number is 59. It means it has 59 protons in its nucleus.
Its standard atomic weight is 140.9
It is a rare earth metal and lanthanide as well.
It has a double hexagonal close packed structure.
It is found as solid at STP.
Its oxides are weakly basic in nature.
Melting point of praseodymium is 935 ℃.
Boiling point of praseodymium is 3130 ℃.
Its density is 6.77 g.cm-3.
Like other rare earth metals its +3 oxidation state is most common.
It is soft, malleable and ductile metals.
It shows magnetic, electrical and optical properties as well.
According to the Pauling scale, its electronegativity is 1.13
It is a monoisotopic element. It is composed of only one isotope which is 141Pr.
It has a greyish white appearance. Its ions are found in yellow green color.
It is paramagnetic at room temperature.
Reaction with air – Praseodymium reacts with oxygen when left exposed to air and forms a green layer of its oxide Pr2O3. Reaction is given below –
4Pr + 3O2 🡪 2Pr2O3
Burning of Praseodymium – Pr burns readily at 150 ℃ on giving heat and forms praseodymium oxide. Reaction is given below –
12Pr + 11O2 → 2Pr6O11
Reaction with water – Pr reacts with hot water readily and forms praseodymium hydroxide. Reaction is given below –
2Pr(s) + 6H2O(l) → 2Pr(OH)3(aq) + 3H2(g)
Reaction with Halogens – Pr reacts with all halogens and forms trihalides. Reactions are given below –
2Pr(s) + 3F2(g) → 2PrF3(s)
2Pr(s) + 3Cl2(g) → 2PrCl3(s)
2Pr(s) + 3Br2(g) → 2PrBr3(s)
2Pr(s) + 3I2(g) → 2PrI3(s)
Reaction with acid – Pr reacts readily with dilute sulfuric acid and forms Pr+3 ions in the solution. These ions form [Pr(H2O)9]3+ complexes. Reaction is given below –
2Pr(s) + 3H2SO4(aq) → 2Pr3+(aq) + 3SO4(aq)-2 + 3 H2 (g)
Uses of Praseodymium
Due to its magnetic, electrical and optical properties praseodymium is used in various fields. Few of its main uses are listed below –
It is used in glass coloration. Leo Moser discovered its use in glass coloration in the 1920s.
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Green Praseodymium Glass Bead
Its small amounts are used in formation of alloys such as mischmetal and ferrocerium etc.
In combination with Nd, praseodymium is used to form high power magnets which are highly durable.
Its alloy with Mg is used in aircraft engines.
It is used in carbon arc lights which are commonly used in film studios.
It is used in coloration of ceramics and porcelain enamels as well.
Its magnetic property is used with various other metals such as nickel and silicate crystals etc. for various purposes.
It is used as a single mode fiber optical amplifier.
It is doped in fluoride glass and silicate crystals and then resultant substances are used in many purposes such as to slow a light pulse down to a few hundred meters per second.
It is used as a catalyst with ceria.
Its ions are used as activators in some UV phosphors.
Praseodymium: Summary in Tabular form
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FAQs on Praseodymium and Its Chemical Properties and Applications
1. What is praseodymium?
Praseodymium is a chemical element with the symbol Pr and atomic number 59, belonging to the lanthanide series of rare earth elements. It is a soft, silvery metal that tarnishes in air. Key facts include:
- Group: Lanthanide (f-block)
- Atomic mass: approximately 140.91 g/mol
- Common oxidation state: +3
- Occurs naturally in minerals such as monazite and bastnäsite
Praseodymium is widely studied in inorganic chemistry due to its magnetic and optical properties.
2. What is the electron configuration of praseodymium?
The electron configuration of praseodymium (Pr, Z = 59) is [Xe] 4f3 6s2. This means:
- The core electrons correspond to the noble gas xenon (Xe)
- There are 3 electrons in the 4f subshell
- There are 2 electrons in the 6s subshell
The presence of partially filled 4f orbitals gives praseodymium its characteristic lanthanide chemistry and magnetic behavior.
3. What are the common oxidation states of praseodymium?
The most common oxidation state of praseodymium is +3, although +4 can also occur in certain compounds. In detail:
- Pr3+ is the most stable and prevalent state in aqueous and solid compounds.
- Pr4+ is found in strong oxidizing environments, such as in PrO2.
Like other lanthanides, the +3 oxidation state dominates due to the relative stability of losing the two 6s electrons and one 4f electron.
4. How does praseodymium react with oxygen?
Praseodymium reacts with oxygen to form oxides such as Pr2O3 and PrO2. A typical balanced reaction in air is:
4Pr(s) + 3O2(g) → 2Pr2O3(s)
- The metal tarnishes slowly in air due to oxide formation.
- At higher temperatures, oxidation occurs more rapidly.
This behavior is typical of reactive lanthanide metals.
5. How does praseodymium react with water?
Praseodymium reacts slowly with cold water and more rapidly with hot water to form praseodymium hydroxide and hydrogen gas. The balanced equation is:
2Pr(s) + 6H2O(l) → 2Pr(OH)3(aq) + 3H2(g)
- The product Pr(OH)3 contains praseodymium in the +3 oxidation state.
- Hydrogen gas (H2) is released.
This reaction demonstrates the typical reactivity of lanthanides with water.
6. What are the uses of praseodymium in chemistry and industry?
Praseodymium is used mainly in alloys, magnets, glass coloring, and ceramics due to its unique electronic properties. Important uses include:
- Component of strong permanent magnets (with neodymium)
- Coloring agent producing yellow-green shades in glass and enamel
- Alloying element in aircraft engine metals
- Laboratory research in lanthanide coordination chemistry
Its optical transitions from 4f electrons are responsible for its distinctive coloration effects.
7. Why is praseodymium considered a rare earth element?
Praseodymium is considered a rare earth element because it belongs to the lanthanide series and is found dispersed in low concentrations in minerals. Specifically:
- It is part of the f-block elements (atomic numbers 57–71).
- It occurs mixed with other lanthanides in ores like monazite.
- It is not truly rare but is difficult to separate chemically.
The term "rare earth" refers more to extraction difficulty than actual scarcity.
8. What is the molar mass of praseodymium?
The molar mass of praseodymium is approximately 140.91 g/mol. This value:
- Represents the mass of one mole of Pr atoms.
- Is based on its naturally occurring isotopic composition.
This molar mass is used in stoichiometric calculations involving praseodymium compounds such as PrCl3 or Pr2O3.
9. What type of element is praseodymium in the periodic table?
Praseodymium is a lanthanide metal located in the f-block of period 6 in the periodic table. Its classification includes:
- Category: Inner transition metal
- Block: f-block
- Period: 6
As an inner transition metal, it has partially filled 4f orbitals that influence its chemical and magnetic properties.
10. What are some common compounds of praseodymium?
Common praseodymium compounds include Pr2O3, PrO2, and PrCl3, typically containing Pr in the +3 or +4 oxidation state. Examples:
- Pr2O3: praseodymium(III) oxide
- PrO2: praseodymium(IV) oxide
- PrCl3: praseodymium(III) chloride
These compounds are important in inorganic synthesis, catalysis research, and materials chemistry.
