Three-dimensional open framework built from Cu-S icosahedral clusters and its photocatalytic property.

Reported here is an extraordinary and unprecedented sulfide containing icosahedral [Cu8S12]16- clusters that behave like a pseudo-octahedral unit in the bonding pattern and are linked through two monomeric GeS4(4-) and four dimeric Ge2S6(4-) units into a covalent 3-D open framework. Its large Cu to Ge ratio is highly unusual in 3-D open-framework sulfides and contributes to its low electronic band gap and the visible light photocatalytic activity.