  Perovskite minerals form an essential component of the Earth's mantle, and
synthetic crystals are ubiquitous in electronics, photonics, and energy
technology. The extraordinary chemical diversity of these crystals raises the
question on how many and which perovskites are yet to be discovered. Here we
show that the "no-rattling" principle postulated by Goldschmidt in 1926,
describing the geometric conditions under which a perovskite can form, is much
more effective than previously thought, and allows us to predict new
perovskites with a fidelity of 80%. By supplementing this principle with
inferential statistics and internet data mining we establish that currently
known perovskites are only the tip of the iceberg, and we enumerate ninety
thousand hitherto-unknown compounds awaiting to be studied. Our results suggest
that geometric blueprints may enable the systematic screening of millions of
compounds, and offer untapped opportunities in structure prediction and
materials design.
