Bond Network Topology and Antiferroelectric Order in Cuprice CuOH

Using
density functional theory (DFT) and a graph theory based approach,
we investigated the topology of bond network in CuOH(s) (cuprice)
considering only symmetry-distinct structures. In parallel, we conducted
the synthesis and X-ray diffraction characterization of the compound
and used the combined theoretical–experimental effort to validate
the lowest energy structure obtained with DFT. The ground-state structure
of CuOH(s) consists of compact trilayers of CuOH connected to each
other via hydrogen bonds, where the inner layer of each trilayer is
composed entirely of Cu atoms. Each trilayer is a dense fabric made
of two interlocked arrays of polymer [CuOH]n chains. This structure corresponds to an antiferroelectric
configuration where the dipole moments of CuOH molecules belonging
to adjacent arrays are antiparallel and are arranged in the same way
as the water molecules in ice-VIII. It is shown that a collective
electrostatic interaction is the main driving force for the cation
ordering while the local atomic configuration is maintained. These
findings and the possibility of synthesizing exfoliated two-dimensional
cuprice are important for some technological applications.