What color indicates the presence of lithium ions during a flame test?

The presence of lithium ions during a flame test is indicated by a crimson color. In a flame test, different metal ions produce characteristic colors when subjected to a flame due to the excitation of electrons. For lithium, when heated, the energy absorbed by the electrons promotes them to higher energy levels. When these electrons return to their original ground state, they release energy in the form of visible light, which for lithium specifically manifests as a distinct crimson or red color. This characteristic is useful in identifying lithium in various compounds and confirms its presence based on the unique spectral line emission associated with lithium ions.