Three analogous phyllosilicates were synthesized via a sol−gel process from the reaction of magnesium ions with aminated trialkoxysilanes in an aqueous basic medium at 373 K. The inorganic−organic hybrids obtained, designated as SILMgx (x = 1−3) are related to [3-aminopropyl]-, [N-(2-aminoethyl)-3-aminopropyl]-, and [(10-amino)-4,7-diazanonyl]trimethoxysilane, respectively. The elemental analysis of these hybrids gave the following C/N ratios:  3.1, 2.5, and 2.4. Thermal analysis data showed 50.7, 56.2, and 58.0% weight losses for the same sequence of hybrids. However, the thermal stability decreased in the order SILMg1 > SILMg2 > SILMg3. The surface areas of these matrixes are <2.0 m2 g-1 and X-ray diffraction patterns gave lamellar distances of 1745, 2063, and 2323 pm for SILMgx (x = 1−3). The infrared data indicated the existence of a phyllosilicate structure with absorption at 540 cm-1, which is associated with vibration of the Mg−O group. 29Si NMR showed the presence of three silicon species:  T1, T2, and T3 in the inorganic−organic backbone structure. The photomicrographs obtained by scanning electron microscopy showed in all cases well-formed particles that have irregular shapes and particle sizes.