Atomic number: 59 Symbol: Pr
Average atomic weight: 140.90765(2) u
| Isotope | Fraction | Atomic weight/u |
| 141 | 1.0000(0) | 140.9076528(26) |
Atomic weights and isotopic compositions were obtained from NIST Database 144
(Atomic Line List 2.05b16, compiled on Jan 13, 2012)