A novel hydroxo-bridged ferric bisubstituted Keggin heteropolytungstate dimer: synthesis and crystal structure of (Me4N)10[Fe4(OH)4(PW10O37)2]·15H2O

Abstract The previously unknown heteropolytungstate (Me 4 N) 10 [Fe 4 (OH) 4 (PW 10 O 37 ) 2 ]·15H 2 O has been prepared by the reaction of Δ–Na 8 HPW 9 O 34 and FeCl 3 in aqueous solution, and characterized by elemental analysis, infrared spectrum as well as X-ray single crystal structure determination. Four bridging hydroxo groups link with four Fe III ions, forming an eight-member ring; and this Fe 4 (OH) 4 aggregation is sandwiched by two bi-vacant Keggin type heteropolyanion fragments. The bridging hydroxo groups are divided into two classes: one is the hydroxo groups linking two PW 10 Fe 2 half moieties, the other is the hydroxo group linking two FeO 6 octahedra in each half moiety. The location of the bridging hydroxo groups is identified by the bond valence sum (BVS) calculations for various oxygen atoms.