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Abstract

The computational design of new and interesting inorganic
materials is still an ongoing challenge. The motivation of
these efforts is to aid the often difficult task of crystal
structure determination, to rationalize different but related
structure types, or to help limit the domain of structures that
are possible in a given system. Over the past decade,
simulation methods have continuously evolved towards the
prediction of new structures using minimal input information in
terms of symmetry, cell parameters, or chemical composition. So
far, this task of identifying candidate structures through an
analysis of the energy landscape of chemical systems has been
particularly successful for predominantly ionic systems with
relatively small numbers of atoms or ions in the simulation
cell. After an introductory section, the second section of this
work presents the historical developments of such simulation
methods in this area. The following sections of the work are
dedicated to the introduction of the building unit concept in
simulation methods: we present simulation approaches to
structure prediction employing both primary (aggregate of
atoms) and secondary (aggregate of coordination polyhedra)
building units. While structure prediction with primary units
is a straightforward extension of established approaches, the
AASBU method (automated asssembly of secondary building units)
focusses on the topology of network-based structures. This
method explores the possible ways to assemble predefined
inorganic building units in three-dimensional space, opening
the way to the manipulation of very large building units (up to
84 atoms in this work). As illustrative examples we present the
prediction of candidate structures for Li4CO4, the
identification of topological relationships within a family of
metalphosphates, ULM-n and MIL-n, and finally the generation of
new topologies by using predefined large building units such as
a sodalite or a double-four-ring cage, for the prediction of
new and interesting zeolite-type structures.