Praseodymium (Pr)
Element 59 · Lanthanide · atomic mass 140.91 u · f-block, period 6
Electron shells: 2, 8, 18, 21, 8, 2
Praseodymium turns glass a deep yellow-green and blocks infrared glare, which is why glassblowers wear it in their goggles. Alloyed with neodymium it strengthens magnets.
Glassblowers' didymium goggles filter out the blinding sodium flare so they can see the glass.
- Atomic number
- 59
- Atomic mass
- 140.91 u
- Electron configuration
- [Xe] 6s² 4f³
- Group · period · block
- f-block · 6 · f
- Oxidation states
- +3
- Electronegativity
- 1.13 (Pauling)
- Melting point
- 931 °C
- Boiling point
- 3,520 °C
- Density
- 6.77 g/cm³
- State at 20 °C
- Solid
- Appearance
- Soft, silvery metal
- Discovered
- Carl Auer von Welsbach, 1885
59 protons, and 59 electrons when neutral
IUPAC standard atomic weight
Shown in the strip below the table
What Praseodymium is used for
- Welding and glassblowing goggles
- High-strength permanent magnets
- Yellow glass and ceramic pigments
- Aircraft engine alloys
Atomic structure of Praseodymium
A neutral praseodymium atom has 59 protons and 59 electrons. Its most common isotope carries about 82 neutrons, which is where the mass number 141 comes from. Change the neutron count and you have a different isotope of praseodymium; change the proton count and you have a different element entirely.
Those electrons fill shells from the inside out: 2, 8, 18, 21, 8, 2. In orbital notation that is [Xe] 6s² 4f³. As a f-block element its valence count is variable, which is why it can form compounds in several oxidation states.
3D electron orbitals
See where Praseodymium's electrons actually are — a cloud of 26,000 points sampled from the probability density |ψ|², not a cartoon of a lobe.
Where Praseodymium sits in the periodic table
Discovery and naming
Praseodymium was discovered by Carl Auer von Welsbach in 1885. Its name comes from Greek prasios didymos, "green twin".
Keep exploring
Atomic weight from IUPAC/CIAAW; physical properties from PubChem (US National Library of Medicine). Values that have never been measured are shown as “not measured” rather than estimated.
Related Calculators
Frequently Asked Questions
What is the atomic mass of Praseodymium?
The standard atomic weight of Praseodymium is 140.91 u, as published by IUPAC's Commission on Isotopic Abundances and Atomic Weights.
How many protons, neutrons and electrons does Praseodymium have?
Praseodymium has 59 protons, because the atomic number is the proton count and that is what makes an atom Praseodymium at all. A neutral Praseodymium atom has the same number of electrons, 59. The neutron count varies by isotope; the most common one has about 82, since 141 − 59 = 82.
What is the electron configuration of Praseodymium?
The electron configuration of Praseodymium is [Xe] 6s² 4f³. Its electrons are arranged 2, 8, 18, 21, 8, 2 across 6 shells.
Is Praseodymium a metal?
Yes. Praseodymium is classified as a lanthanide, on the metallic side of the table.
What group and period is Praseodymium in?
Praseodymium sits in the f-block strip below the main table, in period 6, among the lanthanides. Elements in that strip are not given a group number in the standard 18-column layout.
What is the charge of Praseodymium?
Praseodymium most commonly forms a 3+ ion. Like most transition metals it has several accessible oxidation states, so the charge depends on the compound.
What is the melting point of Praseodymium?
Praseodymium melts at 931 °C and boils at 3,520 °C. That puts it in the solids at everyday temperatures.
What is Praseodymium used for?
Welding and glassblowing goggles, High-strength permanent magnets, Yellow glass and ceramic pigments, Aircraft engine alloys. Praseodymium turns glass a deep yellow-green and blocks infrared glare, which is why glassblowers wear it in their goggles.
Who discovered Praseodymium, and where does its name come from?
Praseodymium (Pr) was discovered by Carl Auer von Welsbach in 1885. The name comes from Greek prasios didymos, "green twin".