Rubidium bromide is an inorganic compound with the chemical formula RbBr. It is a salt of hydrogen bromide. It consists of bromide anions Br− and rubidium cations Rb+. It has a NaCl crystal structure, with a lattice constant of 685 picometres.

There are several methods for synthesising rubidium bromide. One involves reacting rubidium hydroxide with hydrobromic acid:

Another method is to neutralize rubidium carbonate with hydrobromic acid:

Rubidium metal would react directly with bromine to form RbBr, but this is not a sensible production method, since rubidium metal is substantially more expensive than the carbonate or hydroxide; moreover, the reaction would be explosive.

• WebElements. URL accessed March 1, 2006.