Nd(NiO2)2 crystallizes in the orthorhombic Cmce space group. Nd(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NdO6 octahedra that share corners with four equivalent Nd(1)O6 octahedra, corners with eight equivalent Ni(1)O4 tetrahedra, and edges with two equivalent Ni(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 60°. Ni(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form NiO4 tetrahedra that share corners with four equivalent Nd(1)O6 octahedra, corners with four equivalent Ni(1)O4 tetrahedra, and  an edgeedge with one Nd(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-65°. There are two inequivalent O sites. In the first O site, O(2) is bonded in a trigonal planar geometry to one Nd(1) and two equivalent Ni(1) atoms. In the second O site, O(1) is bonded to two equivalent Nd(1) and two equivalent Ni(1) atoms to form a mixture of distorted edge and corner-sharing ONd2Ni2 tetrahedra.
Nd(NiO2)2 crystallizes in the orthorhombic Cmce space group. Nd(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NdO6 octahedra that share corners with four equivalent Nd(1)O6 octahedra, corners with eight equivalent Ni(1)O4 tetrahedra, and edges with two equivalent Ni(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 60°. Both Nd(1)-O(2) bond lengths are 2.40 Å. All Nd(1)-O(1) bond lengths are 2.38 Å. Ni(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form NiO4 tetrahedra that share corners with four equivalent Nd(1)O6 octahedra, corners with four equivalent Ni(1)O4 tetrahedra, and  an edgeedge with one Nd(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-65°. Both Ni(1)-O(1) bond lengths are 2.00 Å. There is one shorter (1.89 Å) and one longer (1.91 Å) Ni(1)-O(2) bond length. There are two inequivalent O sites. In the first O site, O(2) is bonded in a trigonal planar geometry to one Nd(1) and two equivalent Ni(1) atoms. In the second O site, O(1) is bonded to two equivalent Nd(1) and two equivalent Ni(1) atoms to form a mixture of distorted edge and corner-sharing ONd2Ni2 tetrahedra.