The exponential increase in crystal structures deposited in databases such as the inorganic crystal structure database (ICSD ) and Cambridge structural database (CSD 2 ) continually expands our exploration of a multi-dimensional "structure-composition" (S-C) space. The arrangement of atoms and their types defined within this S-C space is intrinsically linked to all physical properties of a material; if two materials are proximate in S-C space, their properties are similar. For example, diamond and cubic boron nitride both adopt a cubic diamond structure, and carbon atoms are chemically similar to both boron and nitrogen. As a result, both materials are super-hard. In contrast, diamond and graphite are compositionally identical but structurally distinct, giving very different properties for these polymorphs.