Cb

Cb is a two-letter abbreviation that can refer to more than one concept depending on context. Two of its most common uses are as a shorthand for Citizens Band radio and historically as the chemical symbol for Columbium, an older name for the element niobium.

Citizens Band radio refers to a private, two-way radio service for personal or business communications in the 27 MHz (11-meter) band. In the United States and many other countries, the CB band comprises 40 channels typically used with amplitude modulation (AM); modern equipment may also support single sideband (SSB) or data features. CB radios are widely used by truck drivers, hobbyists, and small businesses for short-range communication. Regulations, power limits, and licensing requirements vary by country. Range is typically a few kilometers to several tens of kilometers depending on terrain, antenna, and power.

Columbium, now known as niobium, was historically represented by the symbol Cb in some older chemical literature. Niobium is a transition metal; its modern chemical symbol is Nb. Columbium was discovered in 1801 by Charles Hatchett and named after Colombia (the continent’s name in Latin). In the 19th and early 20th centuries, Cb appeared as the symbol in various publications, but in 1949 IUPAC standardized Nb as the name and symbol. Niobium is valued for strengthening stainless steels and for use in specialty alloys, superconducting materials, and various high-performance applications. The term Columbium remains of historical interest and appears mainly in older texts.