Crystal structure of potassium sodium heptahydrogen hexamolybdocobaltate(III) octahydrate: an extra-protonated B-series Anderson-type heteropolyoxidometalate

• Main Authors: Ki-Min Park, Hea-Chung Joo, Uk Lee
• Format: Article
• Language: English
• Published: International Union of Crystallography 2015-09-01
• Series: Acta Crystallographica Section E: Crystallographic Communications
• Subjects: crystal structure; novel protonated B series Anderson-type polyanion; hexamolybdocobaltate(III); noncentrosymmetric strong hydrogen bond
• Online Access: http://scripts.iucr.org/cgi-bin/paper?S2056989015014784
• ISSN: 2056-9890

The title compound, KNa[CoIII(OH)7{Mo6O17}]·8H2O, was obtained by the ion-exchange technique from K3[Co(μ3-OH)6Mo6O18]·7H2O. Six μ3-O atoms and one O atom of the bridging μ2-O atom are protonated. This novel polyanion protonated by an extra H atom is an unexpected polyanion species among the B-series Anderson-type polyoxidometalates (POMs), [Xn+(μ3-OH)6Mo6O18](6–n)–] (X = heteroatom). The extra H atom (seventh H atom) in the polyanion does not lie on a crystallographic centre of symmetry, but is located at the mid-point between two μ2-O atoms of adjacent polyanions, and forms a very short hydrogen bond [2.430 (5) Å]. The present structure is considered as particularly significant in understanding noncentrosymmetric strong hydrogen bonding.