Vibrational Spectra of Single Crystals. Polymorphic Solids of Cyclohexane-d12

Single crystals of the two polymorphs of cyclohexane‐d₁₂ were grown using miniaturized high‐pressure instrumentation. The infrared spectrum of a single crystal of solid I supports a cubic crystal structure with $T_h^2$ space group symmetry for this solid modification. Polarized infrared spectra of a single crystal of solid II and the infrared and laser‐excited Raman spectra of a polycrystalline film were also measured. The splitting of the fundamental vibrational bands and the polarized infrared data are compatible with the previous results on cyclohexane‐d₀ and confirm an orthorhombic $D_{\text{2h}}$ crystal structure.