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About Praseodymium

Praseodymium Bohr

In 1841, Carl Gustav Mosander obtained a novel oxide from his experiments with rare-earth containing minerals. He believed this compound to be an oxide of a new rare earth element that he called didymium, and this element was included on an early version of Dmitri Mendeleev’s periodic table. Later experiments by Austrian chemist Carl Auer Welsbach in 1885 showed that this oxide was actually a mixture of salts of two new elements, which were subsequently named praseodymium and neodymium. Praseodymium salts are yellow-green in solution, leading to the naming of the compound from the Greek word prasinos, meaning green, and the previously chosen root didymos, meaning twin.

Like many of the rare earth elements, praseodymium is used primarily in small amounts to “dope” other materials, as its presence even in small concentrations imparts useful properties. In many cases, praseodymium is used to alter optical properties or in light production or detection applications. Praseodymium is one of the rare earth elements found in didymium glass, which is used in safety goggles that block potentially harmful intense ultraviolet, infrared, and yellow light produced by during some types of welding and glassworking. Fluoride glass doped with praseodymium can be used as a fiber optical amplifier for use with light around a wavelength of 1300nm. Praseodymium-doped crystals are used as gain media in solid-state lasers. Praseodymium is one of several rare earths used to produce extremely bright carbon arc lights, though these are becoming much more rarely used in their primary application in the motion picture industry. Praseodymium compounds can be used yield either a yellow or yellow-green coloring, depending on the application; in glass and enamel, praseodymium is used for yellow coloring. Adding praseodymium to cubic zirconia produces a yellow-green stone which mimics the mineral peridot. Modern medical computed tomography (CT) scanners often use praseodymium-doped scintillator crystals in their X-ray detecting sensors.

Additionally, praseodymium is used as a dopant in alloying applications, catalysts, and other novel materials. Small amounts of praseodymium alloyed with magnesium produce high-strength metals used in demanding applications such as jet engines. Praseodymium-nickel alloys exhibit an extremely strong magnetocaloric effect and have been used in refrigeration devices to attain extremely low temperatures. Praseodymium is used in small amounts in neodymium magnets, which are the strongest permanent magnets commercially available. Praseodymium-doped ceria can be used to catalyze a variety of reactions. Praseodymium-doped thin films are being investigated due to a variety of potentially useful properties including photoluminescence. Praseodymium-doped yttrium silicate crystals are used in quantum computing research.

Praseodymium nickelates, praseodymium doped ceria, and praseodymium barium copper oxide are all being researched as cathode materials for solid oxide fuel cells. Historically, the rare-earth alloy mischmetal was used in lighter flints, and modern flints still contain small amounts of praseodymium along with other rare earths. Finally, praseodymium oxide thin-film surface coatings provide antireflective properties and durability.

Praseodymium is one of the light rare earths and is typically sourced, along with other elements from that group, from the minerals monazite and bastnasite.


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High Purity (99.999%) Praseodymium Oxide (Pr2O3) Powder Praseodymium is highly valued in glass and ceramic production as a bright yellow pigment. Much research is being done on its optical properties for use in amplification of telecommunication systems, including as a doping agent in fluoride fibers. High Purity (99.999%) Praseodymium (Pr) Sputtering TargetPraseodymium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Metallic forms include pellets, rod, wire, and granules for evaporation source material purposes. Praseodymium oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Praseodymium is also available in soluble forms including praseodymium chloride, praseodymium nitrate, and praseodymium acetate. These compounds can be manufactured as solutions at specified stoichiometries.

Praseodymium Properties

Praseodymium (Pr) atomic and molecular weight, atomic number and elemental symbol Praseodymium is a Block F, Group 3, Period 6 element. The number of electrons in each of praseodymium's shells is 2, 8, 18, 21, 8, 2 and its electronic configuration is [Xe]4f3 6s2. Praseodymium Bohr ModelIt resembles the typical trivalent rare earths, however, it will exhibit a +4 state when stabilized in a zirconia host. Unlike other rare earth metals, which show antiferromagnetic and / or ferromagnetic ordering at low temperatures, praseodymium is paramagnetic at any temperature above 1 K. Praseodymium is found in the minerals monazite and bastnasite. Praseodymium was discovered by Carl Auer von Welsbach in 1885. The origin of the element name comes from the Greek words 'prasios didymos' meaning green twin.

Symbol: Pr
Atomic Number: 59
Atomic Weight: 140.9077
Element Category: Lanthanide
Group, Period, Block: n/a, 6, f
Color: silvery white, yellowish tinge
Other Names: Praseodym, Praséodyme
Melting Point: 931°C, 1707.8°F, 1204.15 K
Boiling Point: 3520°C, 6368°F, 3793.15 K
Density: 6779  kg·m3
Liquid Density @ Melting Point: 6.50 g·cm3
Density @ 20°C: 6.77 g/cm3
Density of Solid: 6640 kg·m3
Specific Heat: 0.046 Cal/g/K @ 25°C
Superconductivity Temperature: N/A
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 11.3
Heat of Vaporization (kJ·mol-1): 357
Heat of Atomization (kJ·mol-1): 356.69
Thermal Conductivity: 0.125 W/cm/K @ 298.2 K
Thermal Expansion: (r.t.) (poly) 6.7 µm/(m·K)
Electrical Resistivity: 68 nΩ-cm @ 25°C
Tensile Strength: N/A
Molar Heat Capacity: 27.20 J·mol-1·K-1
Young's Modulus: ( form) 37.3 GPa
Shear Modulus: ( form) 14.8 GPa
Bulk Modulus: ( form) 28.8 GPa
Poisson Ratio: ( form) 0.281
Mohs Hardness: N/A
Vickers Hardness: 400 MPa
Brinell Hardness: 481 MPa
Speed of Sound: (20 °C) 2280 m·s-1
Pauling Electronegativity: 1.13
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.07
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 2.87
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 59
Protons: 59
Neutrons: 82
Electron Configuration: [Xe]4f3 6s2
Atomic Radius: 182 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 203±7 pm
Covalent Radius (Å): 1.9
Van der Waals Radius: 239 pm
Oxidation States: 4, 3, 2 (mildly basic oxide)
Phase: Solid
Crystal Structure: Hexagonal
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) 92.786
1st Ionization Energy: 527 kJ·mol-1
2nd Ionization Energy: 1020 kJ·mol-1
3rd Ionization Energy: 2086 kJ·mol-1
CAS Number: 7440-10-0
EC Number: 231-120-3
MDL Number: MFCD00011174
Beilstein Number: N/A
SMILES Identifier: [Pr]
InChI Identifier: InChI=1S/Pr
PubChem CID: 23942
ChemSpider ID: 22384
Earth - Total: 129 ppb
Mercury - Total: 99 ppb
Venus - Total: 135 ppb
Earth - Seawater (Oceans), ppb by weight: 0.0006
Earth - Seawater (Oceans), ppb by atoms: 0.000026
Earth - Crust (Crustal Rocks), ppb by weight: 8700
Earth - Crust (Crustal Rocks), ppb by atoms: 1300
Sun - Total, ppb by weight: 1
Sun - Total, ppb by atoms: 0.005
Stream, ppb by weight: 0.03
Stream, ppb by atoms: 0.0002
Meterorite (Carbonaceous), ppb by weight: 100
Meterorite (Carbonaceous), ppb by atoms: 10
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: 2
Universe, ppb by atom: 0.02
Discovered By: Carl Auer von Welsbach
Discovery Date: 1885
First Isolation: N/A

Health, Safety & Transportation Information for Praseodymium

Praseodymium is somewhat toxic. Safety data for Praseodymium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) praseodymium.

Safety Data
Signal Word Warning
Hazard Statements H250
Hazard Codes F
Risk Codes 17
Safety Precautions N/A
RTECS Number N/A
Transport Information UN 3208 4.3/PG 1
WGK Germany 3
Globally Harmonized System of
Classification and Labelling (GHS)
Review and Print SDS for Praseodymium Metal


Date Created: 05/15/2015
Date Revised: 05/15/2015


Product Name: Praseodymium Metal

Product Number: All applicable American Elements product codes, e.g. PR-M-02, PR-M-03, PR-M-04, PR-M-05

CAS #: 7440-10-0

Relevant identified uses of the substance: Scientific research and development

Supplier details:
American Elements
1093 Broxton Ave. Suite 2000
Los Angeles, CA 90024
Tel: +1 310-208-0551
Fax: +1 310-208-0351

Emergency telephone number:
Domestic, North America +1 800-424-9300
International +1 703-527-3887


Classification of the substance or mixture
Classification according to Regulation (EC) No 1272/2008
The substance is not classified as hazardous to health or the environment according to the CLP regulation.
Classification according to Directive 67/548/EEC or Directive 1999/45/EC
Not applicable
Information concerning particular hazards for human and environment:
No information known.
Hazards not otherwise classified
No information known.
Label elements
Labelling according to Regulation (EC) No 1272/2008
Not applicable
Hazard pictograms
Not applicable
Signal word
Not applicable
Hazard statements
Not applicable
WHMIS classification
Not controlled
Classification system
HMIS ratings (scale 0-4)
(Hazardous Materials Identification System)

Health (acute effects) = 1
Flammability = 0
Physical Hazard = 0
Other hazards
Results of PBT and vPvB assessment
PBT: Not applicable.
vPvB: Not applicable.


Chemical characterization: Substances
CAS# Description:
7440-10-0 Praseodymium
Identification number(s):
EC number: 231-120-3


Description of first aid measures
After inhalation
Supply fresh air. If required, provide artificial respiration. Keep patient warm.
Seek immediate medical advice.
After skin contact
Immediately wash with water and soap and rinse thoroughly.
Seek immediate medical advice.
After eye contact
Rinse opened eye for several minutes under running water. Then consult a doctor.
After swallowing
Seek medical treatment.
Information for doctor
Most important symptoms and effects, both acute and delayed
No further relevant information available.
Indication of any immediate medical attention and special treatment needed
No further relevant information available.


Extinguishing media
Suitable extinguishing agents
Special powder for metal fires. Do not use water.
For safety reasons unsuitable extinguishing agents
Special hazards arising from the substance or mixture
If this product is involved in a fire, the following can be released:
Advice for firefighters
Protective equipment:
Wear self-contained respirator.
Wear fully protective impervious suit.


Personal precautions, protective equipment and emergency procedures
Wear protective equipment. Keep unprotected persons away.
Ensure adequate ventilation
Environmental precautions:
Do not allow material to be released to the environment without proper governmental permits.
Do not allow product to reach sewage system or any water course.
Do not allow to penetrate the ground/soil.
Methods and material for containment and cleaning up:
Pick up mechanically.
Prevention of secondary hazards:
No special measures required.
Reference to other sections
See Section 7 for information on safe handling
See Section 8 for information on personal protection equipment.
See Section 13 for disposal information.


Precautions for safe handling
Keep container tightly sealed.
Store in cool, dry place in tightly closed containers.
Information about protection against explosions and fires:
No information known.
Conditions for safe storage, including any incompatibilities
Requirements to be met by storerooms and receptacles:
No special requirements.
Information about storage in one common storage facility:
Store away from halogens.
Further information about storage conditions:
Keep container tightly sealed.
Store in cool, dry conditions in well sealed containers.
Specific end use(s)
No further relevant information available.


Additional information about design of technical systems:
Properly operating chemical fume hood designed for hazardous chemicals and having an average face velocity of at least 100 feet per minute.
Control parameters
Components with limit values that require monitoring at the workplace:
Not required.
Additional information:
No data
Exposure controls
Personal protective equipment
General protective and hygienic measures
The usual precautionary measures for handling chemicals should be followed.
Keep away from foodstuffs, beverages and feed.
Remove all soiled and contaminated clothing immediately.
Wash hands before breaks and at the end of work.
Maintain an ergonomically appropriate working environment.
Breathing equipment:
Use suitable respirator when high concentrations are present.
Protection of hands:
Impervious gloves
Check protective gloves prior to each use for their proper condition.
The selection of suitable gloves not only depends on the material, but also on quality. Quality will vary from manufacturer to manufacturer.
Eye protection: Safety glasses
Body protection: Protective work clothing.


Information on basic physical and chemical properties
General Information
Form: Solid
Color: Silver-colored
Odor: Odorless
Odor threshold: Not determined.
pH-value: Not applicable.
Change in condition
Melting point/Melting range: 931 °C (1708 °F)
Boiling point/Boiling range: 3127 °C (5661 °F)
Sublimation temperature / start: Not determined
Flash point: Not applicable
Flammability (solid, gaseous): Product is not flammable.
Powder: highly flammable
Ignition temperature: Not determined
Decomposition temperature: Not determined
Auto igniting: Not determined.
Danger of explosion: Product does not present an explosion hazard.
Explosion limits:
Lower: Not determined
Upper: Not determined
Vapor pressure: Not applicable.
Density at 20 °C (68 °F): 6.773 g/cm³ (56.521 lbs/gal)
Relative density: Not determined.
Vapor density: Not applicable.
Evaporation rate: Not applicable.
Solubility in / Miscibility with Water: Not determined
Partition coefficient (n-octanol/water): Not determined.
dynamic: Not applicable.
kinematic: Not applicable.
Other information
No further relevant information available.


No information known.
Chemical stability
Stable under recommended storage conditions.
Thermal decomposition / conditions to be avoided:
Decomposition will not occur if used and stored according to specifications.
Possibility of hazardous reactions
Powder: contact with water liberates extremely flammable gases.
Conditions to avoid
No further relevant information available.
Incompatible materials:
Oxidizing agents
Hazardous decomposition products:
Metal oxide fum


Information on toxicological effects
Acute toxicity: No effects known.
LD/LC50 values that are relevant for classification: No data
Skin irritation or corrosion: May cause irritation
Eye irritation or corrosion: May cause irritation
Sensitization: No sensitizing effects known.
Germ cell mutagenicity: No effects known.
No classification data on carcinogenic properties of this material is available from the EPA, IARC, NTP, OSHA or ACGIH.
Reproductive toxicity: No effects known.
Specific target organ system toxicity - repeated exposure: No effects known.
Specific target organ system toxicity - single exposure: No effects known.
Aspiration hazard: No effects known.
Subacute to chronic toxicity:
Lanthanons can cause delayed blood clotting leading to hemorrhages.
Exposure may also lead to sensitivity to heat, itching, increased awareness of odor and taste, and liver damage.
Subacute to chronic toxicity: No effects known.
Additional toxicological information:
To the best of our knowledge the acute and chronic toxicity of this substance is not fully known.


Aquatic toxicity:
No further relevant information available.
Persistence and degradability
No further relevant information available.
Bioaccumulative potential
No further relevant information available.
Mobility in soil
No further relevant information available.
Additional ecological information:
General notes:
Do not allow material to be released to the environment without proper governmental permits.
Do not allow undiluted product or large quantities to reach ground water, water course or sewage system.
Avoid transfer into the environment.
Results of PBT and vPvB assessment
PBT: Not applicable.
vPvB: Not applicable.
Other adverse effects
No further relevant information available.


Waste treatment methods
Consult state, local or national regulations to ensure proper disposal.
Uncleaned packagings:
Disposal must be made according to official regulations.


Not a hazardous material for transportation.
UN proper shipping name
Transport hazard class(es)
Packing group
Environmental hazards:
Not applicable.
Special precautions for user
Not applicable.
Transport in bulk according to Annex II of MARPOL73/78 and the IBC Code
Not applicable.
Transport/Additional information:
Not dangerous according to the above specifications.
Marine Pollutant (DOT):


Safety, health and environmental regulations/legislation specific for the substance or mixture
National regulations
All components of this product are listed in the U.S. Environmental Protection Agency Toxic Substances Control Act Chemical substance Inventory.
SARA Section 313 (specific toxic chemical listings)
Substance is not listed.
California Proposition 65
Prop 65 - Chemicals known to cause cancer
Substance is not listed.
Prop 65 - Developmental toxicity
Substance is not listed.
Prop 65 - Developmental toxicity, female
Substance is not listed.
Prop 65 - Developmental toxicity, male
Substance is not listed.
Information about limitation of use:
For use only by technically qualified individuals.
Other regulations, limitations and prohibitive regulations
Substance of Very High Concern (SVHC) according to the REACH Regulations (EC) No. 1907/2006.
Substance is not listed.
The conditions of restrictions according to Article 67 and Annex XVII of the Regulation (EC) No. 1907/2006 (REACH) for the manufacturing, placing on the market and use must be observed.
Substance is not listed.
Annex XIV of the REACH Regulations (requiring Authorisation for use)
Substance is not listed.
REACH - Pre-registered substances
Substance is not listed.
Chemical safety assessment:
A Chemical Safety Assessment has not been carried out.


Safety Data Sheet according to Regulation (EC) No. 1907/2006 (REACH). The above information is believed to be correct but does not purport to be all inclusive and shall be used only as a guide. The information in this document is based on the present state of our knowledge and is applicable to the product with regard to appropriate safety precautions. It does not represent any guarantee of the properties of the product. American Elements shall not be held liable for any damage resulting from handling or from contact with the above product. See reverse side of invoice or packing slip for additional terms and conditions of sale. COPYRIGHT 1997-2016 AMERICAN ELEMENTS. LICENSED GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLY.

Praseodymium Isotopes

Naturally occurring praseodymium (Pr) has one stable isotope: 141Pr.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
121Pr 120.95536(75)# 600(300) ms p to 120Ce; ß+ to 121Ce; ß+ + p to 120La (3/2-) N/A 957.9 -
122Pr 121.95181(54)# 500# ms ß+ to 122Ce N/A N/A 965.98 -
123Pr 122.94596(64)# 800# ms ß+ to 123Ce 3/2+# N/A 983.38 -
124Pr 123.94296(64)# 1.2(2) s ß+ to 124Ce N/A N/A 991.46 -
125Pr 124.93783(43)# 3.3(7) s ß+ to 125Ce 3/2+# N/A 1008.85 -
126Pr 125.93531(21)# 3.12(18) s ß+ to 126Ce (4,5,6) N/A 1016.93 -
127Pr 126.93083(21)# 4.2(3) s ß+ to 127Ce 3/2+# N/A 1025.01 -
128Pr 127.92879(3) 2.84(9) s ß+ to 128Ce (3+) N/A 1042.4 -
129Pr 128.92510(3) 32(3) s ß+ to 129Ce (11/2-) N/A 1050.48 -
130Pr 129.92359(7) 40.0(4) s ß+ to 130Ce (6,7)(+#) N/A 1058.56 -
131Pr 130.92026(6) 1.50(3) min ß+ to 131Ce (3/2+) N/A 1066.64 -
132Pr 131.91926(6) 1.49(11) min ß+ to 132Ce (2+) N/A 1084.03 -
133Pr 132.916331(13) 6.5(3) min ß+ to 133Ce (3/2+) N/A 1092.11 -
134Pr 133.91571(4) ~11 min ß+ to 134Ce (5-) N/A 1100.19 -
135Pr 134.913112(13) 24(2) min ß+ to 135Ce 3/2(+) N/A 1108.27 -
136Pr 135.912692(13) 13.1(1) min ß+ to 136Ce 2+ N/A 1116.35 -
137Pr 136.910705(13) 1.28(3) h EC to 137Ce 5/2+ N/A 1124.43 -
138Pr 137.910755(15) 1.45(5) min EC to 138Ce 1+ N/A 1132.51 -
139Pr 138.908938(8) 4.41(4) h EC to 139Ce 5/2+ N/A 1149.9 -
140Pr 139.909076(7) 3.39(1) min EC to 140Ce 1+ N/A 1157.98 -
141Pr 140.9076528(26) STABLE - 5/2+ 4.136 1166.06 100
142Pr 141.9100448(26) 19.12(4) h EC to 142Ce; ß- to 142Nd 2- N/A 1164.82 -
143Pr 142.9108169(28) 13.57(2) d ß- to 143Nd 7/2+ 0.234 1172.9 -
144Pr 143.913305(4) 17.28(5) min ß- to 144Nd 0- 2.7 1180.98 -
145Pr 144.914512(8) 5.984(10) h ß- to 145Nd 7/2+ N/A 1189.06 -
146Pr 145.91764(7) 24.15(18) min ß- to 146Nd (2)- N/A 1197.14 -
147Pr 146.918996(25) 13.4(4) min ß- to 147Nd (3/2+) N/A 1205.21 -
148Pr 147.922135(28) 2.29(2) min ß- to 148Nd 1- N/A 1203.98 -
149Pr 148.92372(9) 2.26(7) min ß- to 149Nd (5/2+) N/A 1212.06 -
150Pr 149.926673(28) 6.19(16) s ß- to 150Nd (1)- N/A 1220.13 -
151Pr 150.928319(25) 18.90(7) s ß- to 151Nd (3/2)(-#) N/A 1228.21 -
152Pr 151.93150(13) 3.63(12) s ß- to 152Nd 4+ N/A 1226.98 -
153Pr 152.93384(11) 4.28(11) s ß- to 153Nd 5/2-# N/A 1235.05 -
154Pr 153.93752(16) 2.3(1) s ß- to 154Nd (3+,2+) N/A 1243.13 -
155Pr 154.94012(32)# 1# s [>300 ns] ß- to 155Nd 5/2-# N/A 1241.9 -
156Pr 155.94427(43)# 500# ms [>300 ns] ß- to 156Nd N/A N/A 1249.97 -
157Pr 156.94743(43)# 300# ms ß- to 157Nd 5/2-# N/A 1258.05 -
158Pr 157.95198(64)# 200# ms ß- to 158Nd N/A N/A 1256.82 -
159Pr 158.95550(75)# 100# ms ß- to 159Nd 5/2-# N/A 1264.89 -