The crystal and molecular structure of dicyanotris(phenyldiethoxyphosphine)nickel(II), Ni(CN)₂(P(C₆H₅)(OC₂H₅)₂)₃

The crystal and molecular structure of dicyanotris(phenyldiethoxyphosphine)nickel(II), Ni(CN)₂(P(C₆H₅)(OC₂H₅)₂)₃), has been determined from three-dimensional X-ray data collected by counter methods. The structure has been refined by least-squares techniques to a final R factor on F of 6.9%. The material crystallizes in space group C₂ ²-P2₁ of the monoclinic system, with two molecules in a cell of dimensions a = 19.51 (3), b = 9.90 (2), c = 9.65 (2) Å and β - 96° 29 (2)′. The calculated density is 1.265 g/cm³. The absolute configuration of this crystal was inferred by comparison of intensities of Friedel pairs. The inner coordination about the Ni is intermediate between the two idealized five-coordinate geometries- the trigonal bipyramid and the tetragonal pyramid-and is strikingly similar to the geometry about Ni in one of the Ni- (CN)₅ ^3- ions in [Cr(NH₂CH₂CH₂NH₂)₃] [Ni(CN)₅] 1.5H₂O. The Ni and three P atoms are coplanar, with Ni-P bond distances of 2.289 (5), 2.205 (6), and 2.189 (6) Å. The P-Xi-P angle opposite the long Ni-P bond is 133.5 (2)°, while the cyanide groups are bent away from this bond with a C-Ni-C angle of 170.8 (8)°. The Ni-C distances are 1.87 (2) and 1.89 (2) Å, and the Ni-C-N linkages are linear.