The triply-bonded ditungsten complexes W2Cl4(NEt(2))(2)(L-L) (L-L = dmpm, dmpe), W2Cl4(NBu(2))(2)(L-L) (L-L = dmpm, dmpe), and W2Cl4(NHex(2))(2)(dmpm) are formed in the reactions between W2Cl4(NR(2))(2)(NHR(2))(2) (R = Et, Bu, Hex = n-C6H13) and bis(dimethylphosphino)methane (dmpm) or bis(dimethylphosphino)ethane (dmpe). In each case, three isomeric forms have been detected in solution by P-31 {H-1} NMR spectroscopy, and they are formulated as the trans,trans-, cis,trans-, and cis,cis-isomers. Complexes designated cis,trans have one P atom of the bridging diphosphine cis to the N atom on one W atom and another P atom trans to the N atom on the other W atom. The characterization of cis-trans-W2Cl4(NEt(2))(2)(dmpm) (1), cis,cis-W2Cl4(NEt(2))(2)(dmpm) (2), cis,trans-W2Cl4(NEt(2))(2)(dmpm) (3), cis,cis-W2Cl4(NBu(2))(2)(dmpm) (4a, 4b), cis,cis-W2Cl4(NHex(2))(2)(dmpm) (5), cis,trans-W2Cl4(NEt(2))(2)(dmpe) (6), and cis,trans-W2Cl4(NBu(2))(2)(dmpe) (7) has been accomplished by X-ray crystallography. Pertinent crystal data are as follows : for 1, monoclinic space group C2/c, a = 33.210(3) Angstrom, b = 8.725(4) Angstrom, c = 17.052(4) Angstrom, beta = 100.44(1)degrees, Z = 8; for 2, monoclinic space group P2(1)/c, a = 14.958(2) Angstrom, b = 21.028(8) Angstrom, c = 12.778(5) Angstrom, beta = 91.77(3)degrees, Z = 4; for 3, orthorhombic space group Pbca, a = 14.958(2) Angstrom, b = 15.823(2) Angstrom, c = 27.8014(9) Angstrom, Z = 8; for 4a, C2/c, a = 18.011(4) Angstrom, b = 17.221(4) Angstrom, c = 21.264(6) Angstrom, beta = 103.33(2)degrees, Z = 8; for 4b (4a,b are polymorphic), Pbca, a = 14.772(2) Angstrom, b = 17.188(1) Angstrom, c = 25.370(3) Angstrom, Z = 8; for 5, C2/c, a = 18.368(4) Angstrom, b = 17.060(2) Angstrom, c = 30.414(4) Angstrom, beta = 103.96(1)degrees, Z = 8; for 6, P2(1)/c, a = 9.596(2) Angstrom, b = 15.975(2) Angstrom, c = 18.756(4) Angstrom, beta = 96.73(1)degrees, Z = 4; for 7, monoclinic space group P2(1)/n, a = 9.465(1) Angstrom, b = 34.545(7) Angstrom, c = 10.177(4) Angstrom, beta = 97.220(1)degrees, Z = 4. Among them is one unprecedented type of geometrical isomer, namely, the cis,trans-isomers of W2Cl4P2N2 complexes. In order to structurally characterize a trans,trans-isomer for W2Cl4(NR(2))(2)(L-L) molecules, a bis(diphenylphosphino)ethane (dppe) analogue, trans,trans-W2Cl4(NEt(2))(2)(dppe) (8), has been prepared, and it crystallizes with a molecule of toluene, in the space group P2(1)/n with a = 16.396(3) Angstrom, b = 10.104(2) Angstrom, c = 26.680(2) Angstrom, beta = 92.22(1)degrees, and Z = 4. Each of the compounds 1-8 has an essentially staggered W2Cl4P2N2 conformation with the W atoms bound by a triple bond. The W-W distances fall within the narrow range 2.314-2.341 Angstrom. All of them show significant torsion angles in the solid state.