Element Praseodymium
An element of the rare earth family of metals. It has the atomic symbol Pr, atomic number 59, and atomic weight 140.91.
Praseodymium atom is a lanthanoid atom and a f-block element atom.
It is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals. Praseodymium 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.
Names and Identifiers
| Chemical Formula: | Pr |
| CAS: | 7440-10-0 |
| Molecular Weight: | 140.908g/mol |
| EC Number : | 231-120-3 |
| MDL Number: | MFCD00011174 |
| Color: | silvery white, yellowish tinge |
| Other Names: | Praseodym, Praséodyme |
| PubChem CID: | 23942 |
| IUPAC Name: | Praseodymium |
| Inchl: | InChI=1S/Pr |
| InChI Key: | PUDIUYLPXJFUGB-UHFFFAOYSA-N |
| Canonical SMILES: | [Pr] |
| ICSC Number: | n/a |
Physical & Chemical Properties
| Phase: | Solid |
| Density: | 6.77g/cm³ |
| Boiling Point: | 3403 K (3130 °C, 5666 °F) |
| Melting Point: | 1208 K (935 °C, 1715 °F) |
| Molecular Formula: | Pr |
| Flash Point: | n/a |
| Exact Mass: | 140.907593 |
| Symbol: |  |
| Signal Word: | Danger |
| Hazard Statements: | H250 |
| Precautionary Statements: | P222-P231-P422 |
| Hazard Codes: | F: Flammable; |
| Risk Phrases: | R17 |
| Safety Phrases: | 17-7/9-33-16 |
| RIDADR: | UN 3208 4 |
| WGK Germany: | 3 |
| RTECS: | n/a |
| Packaging Group: | III |
| Hazard Class: | n/a |
Praseodymium has only one stable and naturally occurring isotope, 141Pr.
It is thus a mononuclidic element, and its standard atomic weight can be determined with high precision as it is a constant of nature
Naturally occurring isotopes
| Isotope | Mass/Da | Natural abundance (atom %) | Nuclear spin (I) | Magnetic moment (μ/μN) |
|---|---|---|---|---|
| 141Pr | 140.907647 (4) | 100 | 5/2 | 4.136 |
Radiosotope data
| Isotope | Mass/Da | Half-life | Mode of decay | Nuclear spin | Nuclear magnetic moment |
|---|---|---|---|---|---|
| 137Pr | 136.91068 | 1.28 h | EC to 137Ce | 5/2 | |
| 138Pr | 137.91075 | 1.45 m | EC to 138Ce | 1 | |
| 139Pr | 138.90893 | 4.41 h | EC to 139Ce | 5/2 | |
| 140Pr | 139.90907 | 3.39 m | EC to 140Ce | 1 | |
| 142Pr | 141.910041 | 19.12 h | EC to 142Ce; β– to 142Nd | 2 | 0.234 |
| 143Pr | 142.910813 | 13.57 d | β– to 143Nd | 7/2 | 2.7 |
| 144Pr | 143.913301 | 17.28 m | β– to 144Nd | 0 | |
| 145Pr | 144.91451 | 5.98 h | β– to 145Nd | 7/2 |