Sites:
| ChemGlobe: Promethium: Electronic, thermal, and steric data along with an isotope table. | | ChemicalElements.com: Promethium: Basic information, atomic structure, and isotopes. | | EnvironmentalChemistry.com: Promethium: Atomic structure, chemical and physical properties, and table of nuclides. | | It's Elemental: Promethium: Basic physical and historical information. | | LANL: Promethium: History, sources, uses, and properties. | | Lenntech: Promethium: Physical data, chemical properties, health and environmental effects. | | Promethium: Data table and historic information. | | Visual Elements: Promethium: Image, animation, source, uses, and ionisation energies. | | WebElements: Promethium: Extensive information on history, uses, occurrence, compounds, and properties. | | Wikipedia: Promethium: Properties of the element, including its history, applications, and characteristics. |
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