The first ladder structure containing three different squares: the structure of barium 3-carboxy-4-hydroxybenzenesulfonate

Barium sulfonate [Ba2L4(H2O)10] (HL=3-carboxy-4-hydroxybenzenesulfonic acid) was obtained by the reaction of BaCl2·2H2O with NaL in water. X-ray structural analysis reveals that the compound has an undulating ladder structure which is the first ladder structure containing three different kinds of squares.