https://www.selleckchem.com/pr....oducts/epz015666.htm
Reaction of Na9H4[VNb12O40NbO(CO3)2] with [(C6H6)RuCl2]2 (molar ratio VNb12  (C6H6)Ru = 1  4) in aqueous solution gives a mixture of [α-(C6H6)Ru4VNb12O40]7- and [α-(C6H6)Ru3VNb12O40]9-. Direct acetone diffusion into mother liquor leads to crystallization of Na6H[α-(C6H6)Ru4VNb12O40]·41.25H2O (1), characterized by single crystal X-ray diffraction (SCXRD). This anion has four organometallic fragments coordinated to the α-Keggin type [VNb12O40]15- backbone in different manner. Three (C6H6)Ru2+ groups cap triangular faces and one group a