Beschreibung:
Abstract SrC4O4 ·3 H2O, type III. was obtained in an aqueous silica gel besides crystals of SrC4O4-3 H20. type I. X-ray crystal structure analysis showed close relationship to BaC4O4-3H20. but no isotypism. Sr2+ is coord|inated by four water molecules and four oxygen atoms of the squarate dianion. The connection of Sr2+ with C4O4 2- leads to layers. The geometry of C4O4 2- is typical for delocalized π-systems. The Osquarate atoms are not equally bound to Sr2+. One Osquaralc atom (0(4)) is bound to two Sr2+, two (O(1). O(2)) are bound to one Sr2+, respectively, and the fourth Osquaratc atom (0(3)) shows no bonding contact to Sr2+. These differences are compensated for by intermolecular hydrogen bonds which involve O(3) three times, O( I) and O(2) once each, but not O(4).