  An osmium chloride with the chemical formula of OsxCl3 (x = 0.81) was
synthesized and its crystal structure and thermodynamic properties were
investigated. OsxCl3 crystallizes in a layered CdCl2-type structure with the
triangular lattice partially occupied by Os ions on average. However, on
microscopic length scales, the triangular lattice is composed of nano-domains
with a honeycomb arrangement of Os ions, as observed by electron microscopy and
Raman scattering experiments. Magnetization and heat capacity measurements
revealed an absence of magnetic long-range order down to 0.08 K, while a broad
peak in heat capacity at 0.15 K may indicate a short-range order in the local
honeycomb lattice. OsxCl3 may exhibit certain aspects of the Kitaev spin liquid
that are expected for a perfect honeycomb lattice of osmium trichloride.
