Li₂CuO₂

Li2CuO2 is Ilmenite-like structured and crystallizes in the monoclinic Cm space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Li(1)–O(1) bond lengths are 1.97 Å. Both Li(1)–O(2) bond lengths are 1.97 Å. In the second Li site, Li(2) is bonded to one O(2) and three equivalent O(1) atoms to form distorted LiO4 tetrahedra that share corners with six equivalent Li(2)O4 tetrahedra and edges with three equivalent Cu(1)O4 tetrahedra. The Li(2)–O(2) bond length is 2.00 Å. There is one shorter (1.95 Å) and two longer (1.96 Å) Li(2)–O(1) bond lengths. Cu(1) is bonded to one O(1) and three equivalent O(2) atoms to form distorted CuO4 tetrahedra that share corners with six equivalent Cu(1)O4 tetrahedra and edges with three equivalent Li(2)O4 tetrahedra. The Cu(1)–O(1) bond length is 2.00 Å. There is one shorter (1.95 Å) and two longer (1.96 Å) Cu(1)–O(2) bond lengths. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to two equivalent Li(1), three equivalent Li(2), and one Cu(1) atom. In the second O site, O(2) is bonded to one Li(2), two equivalent Li(1), and three equivalent Cu(1) atoms to form a mixture of distorted corner and edge-sharing OLi3Cu3 pentagonal pyramids.