Structure du nitrate de nickel tétrahydraté

Abstract

Crystals of Ni(NO3)2.4HzO were prepared by evaporation of acid solutions of nickel nitrate. The unit cell is monoclinic with a= 5-305, b= 27.24, c= 5.705 A, fl= 114 °, Z= 4. The space group is P21/n. The crystal structure was determined by means of the [100] and [001] electron density projections, performed with the help of Von Eller's Photosommateur. Refinement of atomic coordinates by the least-squares method was achieved with the Univac 1107 computer, using 850 independent reflexions. The final R index is 0.074. Hydrogen atoms were located by difference synthesis and their coordinates were refined by the least-squares procedure. Each nickel atom is surrounded by an octahedron composed of four water molecules and two oxygen atoms belonging to the nitrate ions, which are distorted. Nickel nitrate tetrahydrate has a layer structure: two layers of octahedra parallel to the (010) plane are separated by two layers of nitrate ions. Octahedra are linked together by hydrogen bonds, in the layers and between the layers.

Characterization of Active Material Deposited at the Nickel Hydroxide Electrode by Electrochemical Impregnation

“…4, both HNECI and HNCOR phases show structural features very close to those of an anhydrous nickel hydroxy-nitrate Ni(OH)I.5(NOa)0.a chemically prepared (denoted as HNC). This compound was prepared either by hydrothermal treatment (22) or by slow pyrolysis of Ni(NO3)2 9 6H20 (23). The structure of HNC was studied for the first time by Gallezot and Prettre (22) and later confirmed by Lou~r et el.…”

“…This compound was prepared either by hydrothermal treatment (22) or by slow pyrolysis of Ni(NO3)2 9 6H20 (23). The structure of HNC was studied for the first time by Gallezot and Prettre (22) and later confirmed by Lou~r et el. (23).…”

Crystal data for Zn(NO3)2.4H2O and Zn(NO3)2.2H2O

“…Similar values of lattice constants and the same spacegroup extinctions for zinc nitrate tetrahydrate and nickel nitrate tetrahydrate, whose crystal structure was solved recently (Gallezot et al, 1967) suggest either isomorphism or close relationship of their structures. The determination of the crystal structure of Zn(NO3)2.2H20 is in progress.…”

An X-Ray Structure Determination of the Twinned Crystals of Dinitrato-2,2′-dipyridylsilver(II)

“…The compounds involved are nitratotris(methy1-diphenylphosphine)copper(I) (21), nitratobisdipyridylcopper(I1) nitrate monohydrate (20), trans-dinitratobis(methy1 cyanide)copper(II) (22), potassium tetranitratoaurate(II1) (1 3), nickel nitrate tetrahydrate (14), cis-dinitratobis-(dimethylsulfoxide)palladium(II) (23). Our results on dinitratodipyridylsilver(I1) make a significant addition since they fit into the series Cu(I), Cu(II), Ag(II), Au(II1).…”