Quantum chemistry studies on the hydration activity of Ca3Al2O6 and doped Ca3Al2O6

The valence bond character and hydration activity of the Al6O18 rings and C aOx polyhedra in the molecular structure of Ca3Al2O6 and of the Al6O18 ring s of Ca8.5NaAl6O18 we studied by the SCC-DV-X-alpha method of quantum chemi stry. The calculated results show that the order of reactivity of polyhedra l models in the structure of Ca3Al2O6 is Ca(4)O-9 > Ca(1)O-6 (or Ca(3)O-6) > Al(1)O-4 > Al-2(2)O-4, and the hydration activity of the Al6O18 ring of C a3Al2O6 will decrease if the central hole in the Al6O18 ring is occupied by a Ca atom. The high reactivity of Ca3Al2O6 with water is due to the reacti vity of CaOx polyhedra and the deficiency of holes in the structure. One of the reasons for the decrease of the hydration activity of doped Ca3Al2O6 i s due to sodium ions entering its lattice and leading to a decline of the r eactivity of the Al6O18 ring.