Actinoid Series Elements

**Definition:** A series of radioactive elements from ACTINIUM, atomic number 89, to and including LAWRENCIUM, atomic number 103.

**Tree numbers:** - D01.268.271.100 - D01.496.749.305.100 - D01.552.020

**Synonyms:** - Actinides - Metals, Actinide - Actinoids - Metals, Actinoid