Unoriented and highly oriented films of poly(di-n-hexylsilane) have been studied by Raman scattering, wide angle x-ray diffraction and optical absorption measurements. From a comparison of group theoretical predictions with those bands observed in the Raman experiments and from the x-ray layer line spacing from an oriented sample, a planar zig-zag conformation for the silicon backbone was deduced. X-ray reflections were suitably indexed by a monoclinic unit cell containing two molecules. Polarized Raman studies on uniaxially oriented samples also revealed that the hexyl side chains are not orthogonal to the silicon backbone but may be slightly tilted in order to minimize intramolecular steric interactions. © 1986 American Institute of Physics.