  The honeycomb-lattice ruthenate Li$_2$RuO$_3$ is made heavily Li-deficient by
chemical oxidation by iodine. The delithiation triggers a different phase
Li$_{2-x}$RuO$_3$, the "D-phase", with superlattice. For the first time we
disclose the magnetic and structural properties of the D-phase in the
dimer-solid state. The low temperature magnetic susceptibility and the bond
lengths indicate a bonding configuration consisting of both Ru$^{4+}$-Ru$^{4+}$
and Ru$^{5+}$-Ru$^{5+}$ dimers.
