Structural characterization of Sr4Mg4H4[CoH5]3 shows the importance of support from polarizingcounter ions to 3d transition metal hydrido complexes

Abstract

The structure of the title compound was refined from neutronpowder diffraction data in the cubic space group P-43m (215). The unitcell contains one formula unit with 3 structurally equivalent [Co(I)H5]4-complexes as well as 4 interstitial hydride (H-) ions. The presence ofthe larger and less polarizing Sr2+ ions weakens the bond in thecomplexes and probably also the stability of the structure. Attempts tosynthesize the corresponding Ba analogue failed in contrast to usingsmaller and more polarizing Ca2+ and Yb2+ counterions