Mn3Ni20P6 crystallizes in the cubic Fm-3m space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a distorted tetrahedral geometry to four equivalent Ni(1) atoms. In the second Mn site, Mn(2) is bonded to twelve equivalent Ni(2) and six equivalent P(1) atoms to form distorted MnNi12P6 cuboctahedra that share corners with twenty-four equivalent Ni(1)MnP3 tetrahedra. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one Mn(1) and three equivalent P(1) atoms to form NiMnP3 tetrahedra that share corners with three equivalent Mn(2)Ni12P6 cuboctahedra, corners with six equivalent Ni(1)MnP3 tetrahedra, and edges with three equivalent Ni(1)MnP3 tetrahedra. In the second Ni site, Ni(2) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and two equivalent P(1) atoms. P(1) is bonded in a 8-coordinate geometry to one Mn(2), four equivalent Ni(1), and four equivalent Ni(2) atoms.
Mn3Ni20P6 crystallizes in the cubic Fm-3m space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a distorted tetrahedral geometry to four equivalent Ni(1) atoms. All Mn(1)-Ni(1) bond lengths are 2.46 Å. In the second Mn site, Mn(2) is bonded to twelve equivalent Ni(2) and six equivalent P(1) atoms to form distorted MnNi12P6 cuboctahedra that share corners with twenty-four equivalent Ni(1)MnP3 tetrahedra. All Mn(2)-Ni(2) bond lengths are 2.70 Å. All Mn(2)-P(1) bond lengths are 2.90 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one Mn(1) and three equivalent P(1) atoms to form NiMnP3 tetrahedra that share corners with three equivalent Mn(2)Ni12P6 cuboctahedra, corners with six equivalent Ni(1)MnP3 tetrahedra, and edges with three equivalent Ni(1)MnP3 tetrahedra. All Ni(1)-P(1) bond lengths are 2.26 Å. In the second Ni site, Ni(2) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and two equivalent P(1) atoms. Both Ni(2)-P(1) bond lengths are 2.15 Å. P(1) is bonded in a 8-coordinate geometry to one Mn(2), four equivalent Ni(1), and four equivalent Ni(2) atoms.