Preparation and crystal structure of chromium silicon selenide containing a B12 icosahedron with a tunnel structure

Chromium silicon boron selenide has been prepared by the reaction of chromium diboride and selenium in an evacuated silica tube at a high temperature. The compound is obtained as single crystals in a low yield. The X-ray studies have shown that the structure consists of the three-dimensional framework with a large tunnel and the filling component in the tunnels. The former is made of Si coordinated by four silicon atoms, chromium atoms coordinated by six selenium atoms, and B12 icosahedra. The filling component has a strongly disordered structure and estimated to be a chain of B2Se3. Analysis of the occupational factors of the filling component has indicated that the composition of the compound is CrSi3(B12)Se12·(B2Se3)1.33.