X-ışınları kırınımı yöntemiyle 2-amino 3-metil piridin ammin kadmiyum tetrasiyanonikelatın kristal yapı tayini {Cd (NH3) (C6N2H8) Ni (CN)4}

Abstract

SUMMARY The crystal structure of Cd (NH_) (C.N.Hg) Ni (CN) f was determined from three dimensional intensity data measured with Mo K a radiation on G.E. XRD-700 and Nonius CAD-4 dif fractometers. The crystals are orthorhombic, space group Pna2. with a=13. 535(1)8, b-13. 607 (1) 8, c-7. 645(1)8 and Z=4. The para meters obtained by direct method using SHELXS-84 were full- matrix least squares refined to an R value of 0.034 for 1632 independent reflections. The structure consists of corrugated polymeric two-dimensional networks made up of tetracyano - nickelate ions coordinated to cadmium. The bending in the networks occurs because of a departure of the Ni-C-N-Cd sequence of atoms from linearity at carbon and nitrogen positions. Similar corrugated polymeric layers are also observed in some other related compounds. The coordination around cadmium is a slightly distorted octahedron involving four cyanide nitrogens and the nitrogens of ammonia group as well as the pyridine derivative. Tne average distance from cadmium to these six neighbours is 2.36A. The coordination around nickel is approximatelly square planar. The plane of the four cyanide carbon atoms surrounding Ni at an average distance of 1.868 is tilted so that it makes an angle of 45 to (010). The 2-amino 3-methyl pyridine and ammonia molecules bound to cadmium in trans positions project from both sides of the network. The projections of one network fit into the spaces of the other, so that the layers are arranged as closely as possible. Powder diffraction pattern obtained at liquid nitrogen temperature (T=77 K°) showed no phase tran - sition.

SUMMARY The crystal structure of Cd (NH_) (C.N.Hg) Ni (CN) f was determined from three dimensional intensity data measured with Mo K a radiation on G.E. XRD-700 and Nonius CAD-4 dif fractometers. The crystals are orthorhombic, space group Pna2. with a=13. 535(1)8, b-13. 607 (1) 8, c-7. 645(1)8 and Z=4. The para meters obtained by direct method using SHELXS-84 were full- matrix least squares refined to an R value of 0.034 for 1632 independent reflections. The structure consists of corrugated polymeric two-dimensional networks made up of tetracyano - nickelate ions coordinated to cadmium. The bending in the networks occurs because of a departure of the Ni-C-N-Cd sequence of atoms from linearity at carbon and nitrogen positions. Similar corrugated polymeric layers are also observed in some other related compounds. The coordination around cadmium is a slightly distorted octahedron involving four cyanide nitrogens and the nitrogens of ammonia group as well as the pyridine derivative. Tne average distance from cadmium to these six neighbours is 2.36A. The coordination around nickel is approximatelly square planar. The plane of the four cyanide carbon atoms surrounding Ni at an average distance of 1.868 is tilted so that it makes an angle of 45 to (010). The 2-amino 3-methyl pyridine and ammonia molecules bound to cadmium in trans positions project from both sides of the network. The projections of one network fit into the spaces of the other, so that the layers are arranged as closely as possible. Powder diffraction pattern obtained at liquid nitrogen temperature (T=77 K°) showed no phase tran - sition.