A series of geometry, frequency, and energy calculations of aquabismuth(III) complexes were carried out at up to the MP2/CEP-121G* level. A thorough examination of all species up to and including enneacoordinate species was carried out. The structures of the complexes are compared with experimental data where available. Deviations from the most highly symmetric structures are consistent with the inert-pair effect. In addition, protonated bismuth–oxo clusters of the stoichiometry Bi6O8–n(OH)n(2+n)+, n = 0–4 are examined. The Raman spectrum of bismuth perchlorate with added perchloric and hydrochloric acid is measured.Key words: bismuth, aqua complexes, ab initio, Raman spectra.