Isomorphous compounds [nd (tdtd) 1,5 (pic)3] and [er (tdtd) 1,5 (pic)3] (pic = picrate, tdtd = trans-1,4-dithiane s,s'-dioxide) - Ayala, J D; Vicentini, Geraldo; Delpra, A; Bombieri, G (Acta Crystallographica. Section C, 1994)