Isolation of a Unique Hexanuclear [Bi6O4OH(cit)3(H2O)3]3− Cluster from the Bismuth-Containing Ulcer Healing Agent “Colloidal Bismuth Subcitrate (CBS)”

Abstract
An active ingredient of peptic ulcer healing agent “Colloidal Bismuth Subcitrate (CBS)” has been isolated by crystallization from a solution containing bismuth citrate and ammonia. The single-crystal X-ray structure analysis has demonstrated that it consists of unique anionic hexanuclear bismuth oxo-hydroxo-citrato clusters connected by ammonium ions and weak citrate bridges.