A new good thermal stability hybrid material based on heptamolybdate cluster: Synthesis and structural characterization

•The relatively high thermal stability of the polyoxomolybdates is due to the network of hydrogen bonds and electrostatic interactions•The thermal stability of a polyoxometalate is related to the size of the ammonium cation.•Transition from one polyoxometallate salt to another is possible through substitution reactions at room temperature.