Synthesis and Crystal Structure of RbGdNb6Cl18

Abstract

A new quaternary niobium cluster chloride, RbGdNb₆Cl₁₈ has been prepared by solid state reaction methods. The RbCl, GdCl₃, NbCl₅, and niobium powder were mixed in stoichiometric proportions. This mixture was fed into a sealed quartz tube, and heated at 700ºC for 2 days. A single crystal was selected for use in determining the structure of this compound using a single crystal X-ray diffractometer. It crystallizes in the trigonal system, hexagonal setting with space group R-3 (No. 148). The unit cell parameters are: a = 9.3037(2) Å, c = 25.5752(2) Å, V = 1.917.17(7) ų, and Z =3. The structure consists of discrete cluster units, [Nb₆Cl₁₈]^4- that separated by Rb⁺ and Gd³⁺ cations in a close packed cubic stacking arrangement.