The first single-crystal X-ray structural refinement of the superconducting phase Li0.2(1)ZrNCl derived by intercalation

The single crystals of the superconducting Li0.2(1)ZrNCl have been derived from the single crystals of beta-ZrNCl by intercalation of lithium using an n-butyllithium solution in hexane. The crystal structure has been refined on the basis of the single-crystal X-ray data: the space group R-3m, a = 3.591(1) Angstrom, c = 27.839(6) Angstrom, Z = 6, R1 = 0.0749 for 196 reflections and 12 variables. beta-ZrNCl is isotypic with SmSI, while the structure of Li0.2(1)ZrNCl can be described as the Li intercalated YOF type, a stacking variant of the SmSI type. The tightly bound slabs with a Cl-Zr-N-N-Zr-Cl sequence of close-packed layers are stacked rhombohedrally along the c-axis, with the van der Waals gaps between the chlorine layers hosting Li ions. This is the first single-crystal study on the Li intercalated phase. The structural changes from the pristine single crystals were precisely determined. (C) 2002 Published by Elsevier Science (USA).