2-[(E)-2,6-Dichlorophenylimino]-1-(1-{2-[(E)-2,6-dichlorophenylimino]-imidazolidin-1-yl}-ethyl)-imidazolidine; (2E,2'E)-1,1'-(Ethane-1,1-diyl)bis(N-(2,6-dichlorophenyl)imidazolidin-2-imine); Imidazolidine, 2-[(E)-2,6-dichlorophenylimino]-1-(1-{2-[(E)-2,6-dichlorophenylimino]-imidazolidin-1-yl}-ethyl)-; 2-[(E)-2,6-Dichlorophenylimino]-1-(1-{2-[(E)-2,6-dichlorophenylimino]-imidazolidin-1-yl}-ethyl) imidazolidine; Clonidine Dimer Impurity