Neutron-Diffraction Study of D3Co(CN)6

The crystal structure of D₃Co(CN)₆ has been determined by a neutron‐diffraction analysis of a poly‐crystalline sample at room temperature. The deuterated compound was prepared from H₃Co(CN)₆. It crystallizes according to space group $D_{\text{3d}}^1\text{‐P3̄1m}$ with $\text{a\hspace{0.17em}=\hspace{0.17em}6.431(4) Å}$ and $\text{c\hspace{0.17em}=\hspace{0.17em}5.695(4) Å}$ . The lattice constants do not show any isotope effect within the limits of error. Slightly trigonally distorted Co(CN)₆ octahedra are three‐dimensionally linked by N–D–N bonds. The Co–C, C–N, and N–N distances are 1.88, 1.15, and 2.60 Å, respectively. The latter distance is the shortest so far found in an N–D–N or N–H–N bond. These hydrogen bonds are either linear symmetric or statistically asymmetric (double minimum) centered on $(\frac{1}{2}\text{, 0,}\frac{1}{2})$ .