Single crystals of TMA-CuGS-2, [C4H12N](6)[(CU0.44Ge0.56S2.23)(4)(Ge4S8)(3)], were synthesized hydrothermally, and the structure was determined using data collected from sealed-tube and synchrotron X-ray sources. This compound consists of Ge4S104- adamantine clusters, corner-sharing with MS(x) units (M = Cu, Ge; x = 3 or 4), forming an open framework with tetramethylammonium cations residing within four intersecting channels. Disorder in the M sites causes the composition of the framework to deviate from the ideal stoichiometry, Ge(0.71)M(0.24)S(2), realized when M = Cu and x: = 4. This is consistent with results obtained from electron-probe microanalysis. The structure refinements were carried out in space group <I(4)over bar 3d> with cell parameter alpha = 20.629 (1) Angstrom. Fourteen unique weak reflections of the type hhl, 2h + I = 4n + 2, forbidden in <I(4)over bar 3d>, were detected only in the synchrotron/imaging plate experiment. Trial refinements in space groups R3 and I2(1)3 suggest their origin in either weak ordering or multiple scattering effects.
