Ni₃Cl_2.1(OH)_3.9·4H₂O, the\nNi Analogue to Mg₃Cl₂(OH)₄·4H₂O

Abstract

For the first time a basic transition-metal\nhydrate, Ni₃Cl_2.1(OH)_3.9·4H₂O, is found to be isostructural to a main-group metal phase,\nMg₃Cl_2.0(OH)_4.0·4H₂O. The Ni phase was found as crystalline solid in the course of investigations\ninto the formation of basic nickel­(II) chloride phases at 25 and 40\n°C in alkaline, concentrated nickel­(II) chloride solutions. Ni₃Cl_2.1(OH)_3.9·4H₂O was\ncharacterized by thermal analysis, IR spectroscopy, scanning electron\nmicroscopy, and X-ray powder diffraction. The crystal structure was\ndetermined from high-resolution laboratory X-ray powder diffraction\ndata. Ni₃Cl_2.1(OH)_3.9·4H₂O crystallizes in space group <i>C</i>2/<i>m</i> (12) with <i>Z</i> = 2, <i>a</i> =\n14.9575(4) Å, <i>b</i> = 3.1413(1) Å, <i>c</i> = 10.4818(5) Å, β = 101.482(1)°, and <i>V</i> = 482.50(3) ų. The main building unit\nof the structure is an infinite triple chain of edge-linked distorted\nNiO₆ octahedra. These chains are separated by interstitial\none-dimensional zigzag chains of disordered Cl^– ions\nand H₂O molecules. The crystal structures of Ni₃Cl_2.1(OH)_3.9·4H₂O and the isostructural\nmagnesium salt hydrate Mg₃Cl₂(OH)₄·4H₂O (2–1–4 phase) are compared in\ndetail.