Reactions of 3 and 2 equiv of lithium dimethylamide with ZrCl4 in THF afford dinuclear complexes (Me2N)(3-)Zr(mu-Cl)(2) (mu-NMe2)Zr(NMe2)(2)(THF) (1) and Cl(Me2N)(2)Zr(mu-Cl)(2)(mu-NMe2)Zr(NMe2)(2)(THF) (2), respectively. These complexes were found to have unusual structures containing dichloro(amido) bridges between Zr atoms. Both complexes 1 and 2 crystallize in the monoclinic space group P2(1)/c (a = 8.735(3) Angstrom, b = 21.498(7) Angstrom, c = 13.997(5) Angstrom, beta 92.56(3)degrees, Z = 4 for II a = 8.550(3) Angstrom, b = 20.673(7) Angstrom, c = 14.229(6) Angstrom, beta = 95.11(3)degrees, Z = 4 for 2). Each Zr atom iu 1 and 2 has a trigonal antiprismatic coordination geometry. Reaction of 1 equiv of lithium dimethylamide with ZrCL4 in THF gave the monosubstituted complex as the LiCl adduct (Me2N)(THF)ZrCl2)(mu-Cl)(2)Li(THF)(2) (4), which crystallizes in the triclinic space group (a = 10.078(6) A, b = 11.003(7) Angstrom, c = 11.039(6) Angstrom, alpha = 84.75(5)degrees, beta = 78.38(5)degrees, gamma = 66.65(5)degrees, Z = 2). In 4, the Zr atom has a distorted octahedral coordination geometry. These new amido complexes add to the missing members of the Zr(NMe2)(x)Cl4-x series. The dynamic NMR of 1 has also been studied.