The present invention relates to new organic-inorganic hybrid silicates and metal-silicates called ECS, characterized by an X-ray powder diffraction pattern with reflections exclusively at angular values higher than 4.0° of 2Θ, preferably at angular values higher than 4.7°, and an ordered structure containing structural units having formula (a) wherein R is an organic group: Formula (a) and possibly containing one or more elements T selected from groups III B, IV B, V B and transition metals, with a Si/(Si+T) molar ratio in said structure higher than 0.3 and lower than or equal to 1, wherein Si is the silicon contained in the structural unit (a). A process is also described, starting from disilanes, for the preparation of these materials, which does not include the use of templates or surfactants. These materials can be used as molecular sieves, adsorbents, in the field of catalysis, in the field of electronics, in the field of sensors, in the field of nanotechnologies.