The effect of aluminum on FOX-7 structure was considered.Density functional approach at the level of unrestricted B3LYP/6-311 + + G(d,p) level was adopted.The model considered 1-4 aluminum atoms per FOX-7 molecule.The results show that the molecular geometries as well as many molecular orbital characteristics of FOX-7 molecule are subjected multiplicity of the composites,FOX-7 +nAl (n =1-4).In the case of n =1-2,some conformational changes occur.In the presence of three aluminum atoms,the quartet state of the composite is stable but in the doublet state,one of the N—O bonds ruptures.As for the n =4 case the singlet and triplet states are stable but in the quintet state one of the N—O bonds cleaves.As the number of aluminum atoms increases,the HOMO-LUMO energy gap decreases generally.