By very slow diffusion of aqueous solutions of CoCl2. 6H(2)O and K-6[W4Te4(
CN)(12)]. 5H(2)O through silica gel, single crystals Of [Co(H2(O))(4)](3)[W
4Te4(CN)(12)]. 15.38H(2)O were obtained. A complete X-ray structure determi
nation reveals an extremely porous, three-dimensional neutral cluster-expan
ded framework structure with large water-filled cuboidal cavities.