STRUCTURE OF THE POTASSIUM SALT WITH DIPICRYLAMINE

Article abstract of DOI:10.1107/S0567740880004943

K(1+)*C12H4N7O12(1-), monoclinic, P2₁/a, a = 15.78(2), b = 13.16(3), c = 11.12(2) Angstroem, β = 130(1) deg, D_m = 1.83, D_c = 1.79 Mg m^-3, Z = 4, M_r = 477.32, λ(Cu Kα) = 1.5418 Angstroem, μ(Cu Kα) = 3.577 mm^-1.The structure was solved by direct methods and refined to a final R value of 0.1188 with 1926 visually estimated intensities from Weissenberg photographs (H atoms not refined).Potassium ions are linked to dipicrylamine anions through oxygens in eightfold coordination.The structure is stabilized by van der Waals forces and exists in two equivalent resonating forms.The angle between two planar aromatic rings is 78 deg and the nitro groups are twisted out of these planes by angles varying from 8 to 34 deg.The average values of C=C, C-N(O), C=N and N=O are 1.40(2), 1.46(2), 1.31(1) and 1.23(1) Angstroem respectively.