The coupling reaction between PhMeSiCl2 and Me2SiCl2 in the presence of Na/K alloy resulted in a variety of phenylated permethylcyclohexasilanes of which only trans-1, 4- Ph2Me10Si6 could be obtained in pure form by repeated recrystallizations. It was studied by means of nmr (1H, 13C, and 29Si) and X-ray crystallography. The crystals are monoclinic, P 21/c with a= 10.105 (6), b= 14.77 (1), c= 9.973 (6) Å, β= 94.08 (5)°, V= 1485 (2) Å3, and Z= ...