Combining gene composition and bonding information can potentially reveal the structural significance of the identified genes. In order to explore this aspect, we first interpret each element as a structural entity : S as a sulfate tetrahedron, P as a phosphate tetrahedron, Al as an alumina octahedron, F as a terminal P-F or Al-F bond, or as an Al-F-Al link, and Na as Na + ions attached to F terminal bonds, non-bridging oxygen species, or isolated sulfate tetrahedra. Assumed charge carriers are Na(+) [17, 18] and, eventually, F(-) and O(2-).