rubidium
/ruːˈbɪdiəm/
noun
- A soft, silvery-white metallic chemical element (symbol Rb) that reacts strongly with water and is used in electronics, atomic clocks, and some types of glass.
- Scientists use rubidium in research on quantum computing.
- Rubidium is used in some atomic clocks because of its precise frequency.
- The chemist carefully stored the rubidium in oil to prevent it from reacting with air.