Lone-pair interfaces that divide inorganic materials into ionic and covalent parts
The lone (ar)ranger: The structure of Cu20Sb35O 44Cl37 is divided up into two parts: ionically bonded Cu+-Cl- supertetrahedra (green) and covalently bonded clusters that resemble zeolite β cages. The Sb3+ ions (gray) lie at the vertices of the cages, while their lone pairs of electrons form surfaces that separate the covalent and ionic parts. (Figure Presented).
