A NOVEL HYDROXO-BRIDGED FERRIC BISUBSTITUTED KEGGIN HETEROPOLYTUNGSTATE DIMER - SYNTHESIS AND CRYSTAL-STRUCTURE OF 4N)(10)[FE-4(OH)(4)(PW10O37)(2)]CENTER-DOT-15H(2)O

The previously unknown heteropolytungstate (Me4N)(10)[Fe-4(OH)(4) (PW1 0O37)(2)]. 15H(2)O has been prepared by the reaction of Delta-Na8HPW9O 34 and FeCl3 in aqueous solution, and characterized by elemental analy sis, infrared spectrum as well as X-ray single crystal structure deter mination. Four bridging hydroxo groups link with four Fe-III ions, for ming an eight-member ring; and this Fe4OH)(4) aggregation is sandwiche d by two bi-vacant Keggin type heteropolyanion fragments. The bridging hydroxo groups are divided into two classes: one is the hydroxo group s linking two PW10Fe2 half moieties, the other is the hydroxo group:li nking two FeO6 octahedra in each half moiety. The location of the brid ging hydroxo groups is identified by the bond valence sum (BVS) calcul ations for various oxygen atoms;:(C) 1998 Elsevier Science Ltd. All ri ghts reserved. (C) 1998 Elsevier Science Ltd. All rights reserved.