Iodine

Wikipedia: Lanthanum Wikipedia: Lanthanum- Properties of the element, including its history, applications, and characteristics. Lenntech: Lanthanum Lenntech: Lanthanum- Physical data, chemical properties, health and environmental effects. EnvironmentalChemistry.com: Lanthanum EnvironmentalChemistry.com: Lanthanum- Atomic structure, chemical and physical properties, and table of nuclides. ChemicalElements.com: Lanthanum ChemicalElements.com: Lanthanum- Basic information, atomic structure, and isotopes. It's Elemental: Lanthanum It's Elemental: Lanthanum- Basic physical and historical information.