We have examined the local lattice instability of the (MnO6)(9-) and (MnO6)(8-) complexes embedded in the background potential appropriate for La2-2xSr1+2xMn2O7 at x = 0.40 by ab initio quantum chemical calculations. We confirmed the E circle times e Jahn-Teller instability in the (MnO6)(9-) cluster and E circle times (b(1) + b(2)) Jahn-Teller instability in the (MnO6)(8-) cluster, respectively. (C) 2002 Published by Elsevier Science B.V.