Definition

1. Noun:
   • A chemical element: A soft, silvery-white, highly reactive metallic element belonging to the alkali metal group on the periodic table. Its chemical symbol is Rb, and its atomic number is 37.

Usage and Examples

• Noun:
  • The scientist studied the spectral lines of rb in the laboratory.
  • Due to its violent reaction with water, rb must be stored under mineral oil or in an inert atmosphere.
  • The primary commercial source for rb is the mineral pollucite.

Advanced Usage

• In scientific contexts: The term "rb" is almost exclusively used in chemistry, physics, and materials science. It is often discussed in relation to its properties, such as its use in atomic clocks, specialized glass, and certain types of photocells.
  • The ultra-precise atomic clock utilizes the frequency of a hyperfine transition in rb atoms.

Variants and Related Words

• Rubidium: This is the full, standard name for the element. "Rb" is its chemical symbol.
  • The sample was confirmed to contain traces of rubidium.

Synonyms

• Rubidium: The full name of the element, synonymous with the symbol "Rb".
• Element 37: A reference by its atomic number.

Notes on Different Meanings

• The term "rb" as a standalone noun has a single, specific meaning in the English language: it is the chemical symbol for the element rubidium. It is not used as a common word outside of scientific nomenclature.

Noun

1. a soft silvery metallic element of the alkali metal group; burns in air and reacts violently in water; occurs in carnallite and lepidolite and pollucite