A mixture of polymeric CW6Cl16 (1) and molecular CW6Cl18 (2) is formed in a reproducible reaction by heating purchased WCl4 (contaminated by e.g. C6H2Cl4) in closed silica tubes at 925 K / 915 K. The direct synthesis of 1 from W, WCl5 and CCl4 succeeds at 1030 K / 870 K, but an optimized way to 2 was not yet found (low yield e.g. from W, WCl6 and graphite or from W, WCl6 and C6Cl6; 975 K / 965 K). The black crystals of 1 and 2 become greenish‐gray after grinding and they are not sensitive to hydrolysis and oxidation. 1 is diamagnetic with χmol = —865·10—6 cm3 mol—1 and shows numerous FIR bands. 1 decomposes thermally (870—1060 K) to W and W2C. The 13C NMR chemical shift of solid 1 is observed at +264 ppm. Compound 2 is soluble in DMSO and the green solution shows characteristic absorptions at 12900, 16500 and 24400 cm—1 (13C NMR: δ = 279.9).The crystal structure of 2 represents a hcp arrangement of isolated triprismo‐hexatungsten clusters [(CWCl)Cl] with 6¯m2 symmetry (d(W—W) = 2.743Å (6×), 2.930Å (3×); d¯(W—Cli) = 2.361Å, 2.434Å; d(W—Cla) = 2.377Å; d(W—C) = 2.157Å). In the structure of 1 the same central units are interconnected via four Cla—a bridging ligands to form 2D puckered layers [(CWCl)Cl)Cl]; (d¯(W—W) = 2.658Å (6×), 3.020Å (3×); d¯(W—Cli) = 2.389Å, 2.456Å; d¯(W—Cla) = 2.389Å; d¯(W—Cla—a) = 2.548Å; d¯(W—C) = 2.15Å). Crystal data: 1, CW6Cl16, orthorhombic, Pnma (62), oP92; a = 16.637Å, b = 12.958Å, c = 9.797Å, Z = 4; 2094 hkl, R(F) = 0.036. — 2, CW6Cl18, hexagonal, P6¯2c (190), hP50; a = 8.923Å, c = 17.503Å, c/a = 1.962, Z = 2; 942 hkl, R(F) = 0.048.