The single-crystal structure of excessively Pb2+-exchanged zeolite Y (|Pb2+5.5(Pb4O4(Pb2+0.67Pb4+0.33)4)6|[Si117Al75O384]-FAU) was prepared by the exchange of Na-Y (|Na75|[Si117Al75O384]-FAU, Si/Al = 1.56) with an aqueous stream 0.05 M Pb(C2H3O2)2 at 294 K, followed by vacuum dehydration at 1 � 10-6 Torr and 723 K.  Its single-crystal structure was determined by single-crystal synchrotron X-ray diffraction techniques.  It was refined to the final error indices R1/wR2 = 0.0574/0.1404 in the cubic space group Fd-3m.  In |Pb2+5.5(Pb4O4(Pb2+0.67Pb4+0.33)4)6|[Si117Al75O384]-FAU, about 53.5 Pbn+ ions per unit cell occupy three different equipoints; 24 are at site I', 24 are at site II, and the remaining 5.5 are at another site II.  Eight Pb4+ ions at some of the positions must have higher oxidation states due to elevated dehydration temperature; Pb(IIa) is supposed to coexist of Pb2+ and Pb4+ ions by assumption for the charge balance of zeolite framework.  A distorted Pb4O4 cube, alternating Pb2+ at Pb(I') and O2- at O(5), coordinates with four of Pb2+ and/or Pb4+ ions through its oxygen atoms to give a [Pb2+4O2-4(Pb2+0.67Pb4+0.33)4]32/3+ cluster in six of eight sodalite cavities in zeolite Y.

Preparation and single-crystal structure of lead oxide nanoclusters in zeolite Y, |Pb2+5.5(Pb4O4(Pb2+0.67Pb4+0.33)4)6|[Si117Al75O384]-FAU

246th National Meeting (2013)

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