LEAD-OXIDE HYDROXIDE CLUSTERS IN PB9O(OH)4-A, ZEOLITE-A EXCHANGED WITH PB2+ AT PH 6.0

The crystal structure of Pb9O(OH)4-A, zeolite 4A exchanged with Pb2+ at pH 6.0 and evacuated at 26-degrees-C, has been determined by single-crystal X-ray crystallography. Two separate (Pb2+, OH-, O2-) clusters were found. In each sodalite unit, a (Pb2+)3(O2-)(OH-)3 cluster, a distorted Pb4O4 cube with one Pb2+ missing, coordinates via its oxygens to four Pb2+ ions at 6-ring sites to give [Pb7O(OH)3]9+. In half of the large cavities, a [Pb2(OH)2]2+ cluster may have formed. The remaining Pb2+ ion is near the center of an 8-ring. The oxygen positions are somewhat uncertain, and the presence of hydrogen atoms is inferred.