  Modern compound prediction methods can efficiently screen large numbers of
crystal structure phases and direct the experimental search for new materials.
One of the most challenging problems in alloy theory is the identification of
stable phases with a never seen prototype; such predictions do not always
follow rational strategies. While performing ab initioa data mining of
intermetallic compounds we made an unexpected discovery: even in such a
well-studied class of systems as metal borides there are previously unknown
layered phases comparable in energy to the existing ones. With ab initio
calculations we show that the new metal-sandwich (MS) lithium monoboride phases
are marginally stable under ambient conditions but become favored over the
known stoichiometric compounds under moderate pressures. The MS lithium
monoboride exhibits electronic features similar to those in magnesium diboride
and is expected to be a good superconductor.
