Hierarchy classification:

1. top of the aat hierarchies
2. Materials Facet
3. Materials (hierarchy name)
4. materials (substances)
5. [materials by composition]
6. inorganic material
7. metal
8. [metal by composition or origin]
9. nonferrous metal

Additional parents:

1. top of the aat hierarchies
2. Materials Facet
3. Materials
4. materials
5. materials by form
6. materials by chemical form
7. elements

Anotations

Scope note:

Radioactive, soft, metallic chemical element, atomic number 88; a member of the group of the alkaline earth metals. It occurs in small amounts in pitchblende and other uranium ores. It undergoes spontaneous disintegration to form Radon gas and alpha rays. Bright white radium was formerly used to make luminous paints used in clock dials, doorknobs, and other glow-in-the-dark items prior to the 1970s.