The atomic structure of calcium-silicate-hydrate (C1.67-S-Hx) has been studied.Atomistic C-S-H models suggested in our previous study have been revised in order to perform a direct comparison of energetic stability of the different structures.An extensive set of periodic structures of C-S-H with variation of water content was created, and then optimized using molecular dynamics with reactive force field ReaxFF and quantum chemical semiempirical method PM6.The new geometries of C-S-H, reported in this paper, show lower relative energy with respect to the geometries from the original definition of C-S-H models.Model that corresponds to calcium enriched tobermorite structure has the lowest relative energy and the density closest to the experimental values.