Homometric structures

Homometric structure A structure with a uniquely different arrangement of atoms from another, but having the same sets of interatomic vectors, and hence the same Patterson map. Examples to date consist of homometric heavy-atom positions in crystal structures that also contain lighter atoms. The total crystal structure is not, however, homometric. 

Multiple solutions may exist for one and the same set of vectors in extremely rare cases (homometric structures). No case is known in which two homometric structures are both chemically meaningful. 

CRYSTAL (Homometric Pairs). Two crystal structures having the same x-ray diffraction pattern. This is possible because, basically, a diffraction pattern depends only on the relative vector distances between the atoms in the lattice, not on their absolute positions in space. 

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