Polyhedral Clathrate Hydrates. XIV. The Structure of (CH3)3CNH2·9¾H2O

The crystal structure of 16(CH₃)₃CNH₂·156H₂O has been determined from three‐dimensional x‐ray‐diffraction data obtained at −30°C. The crystals are cubic, space group $\text{I4̄3d}$ , with cell dimensions a=18.81±0.02 Å. The host framework of hydrogen‐bonded water molecules consists of face‐sharing heptakaidecahedra which have three square, nine pentagonal, two hexagonal and three heptagonal faces. The square and pentagonal faces also form octahedra which complete the space‐filling arrangement. The amine molecules occupy the larger polyhedra as nonbonded guests undergoing marked oscillatory motion.