The formula for rubidium iodide, also written as rubidium(I) iodide, is RbI. Rb is the chemical symbol for rubidium, and I is the chemical symbol for iodine.
Because the chemical formula for rubidium iodide contains no numbers, it shows that the molecule contains one atom each of rubidium and iodide. Rubidium iodide can be formed through a reaction of hydroiodic acid and hydroxide, represented by the chemical equation RbOH + HI → RbI + H2O. It can also be formed by reacting rubidium(I) carbonate with hydroiodic acid, as shown in the chemical equation Rb2(CO3) + 2HI → 2RbI + H2O + CO2.