Structure solution from powder data of the hydrous layer silicate kanemite, a precursor of the industrial ion exchanger SKS-6

The crystal structure of kanemite, NaH[Si (sub 2) O (sub 5) ].3H (sub 2) O, has been solved and refined to R 0.103. Kanemite is orthorhombic with a 4.946, b 20.510, c 7.277 Aa; Z = 4; space group Pbcn. The silicate anion in the structure is a single layer of Q (super 3) -[SiO (sub 4) ] tetrahedra building six-membered rings in a chair or boat conformation; the [Si-O] groups of the layer point up and down alternately. The negative charge of the layer is compensated partially with protons and partially with an intercalated layer of octahedrally hydrated Na cations. Although the interlayer bonding is only by delocalized Coulombs interaction and weak hydrogen bridge bonds between the silanol end groups and of the silicate layer and the hydrated Na cations, the crystallinity of the material is sufficient to allow a detailed crystallographic analysis.