Cs3MnI5 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 8-coordinate geometry to two equivalent I(2) and six equivalent I(1) atoms. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to two equivalent I(2) and eight equivalent I(1) atoms. Mn(1) is bonded in a tetrahedral geometry to four equivalent I(1) atoms. There are two inequivalent I sites. In the first I site, I(1) is bonded in a 6-coordinate geometry to two equivalent Cs(2), three equivalent Cs(1), and one Mn(1) atom. In the second I site, I(2) is bonded to two equivalent Cs(2) and four equivalent Cs(1) atoms to form corner-sharing ICs6 octahedra. The corner-sharing octahedral tilt angles range from 0-41°.
Cs3MnI5 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 8-coordinate geometry to two equivalent I(2) and six equivalent I(1) atoms. Both Cs(1)-I(2) bond lengths are 3.90 Å. There are two shorter (3.82 Å) and four longer (4.03 Å) Cs(1)-I(1) bond lengths. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to two equivalent I(2) and eight equivalent I(1) atoms. Both Cs(2)-I(2) bond lengths are 4.13 Å. All Cs(2)-I(1) bond lengths are 4.26 Å. Mn(1) is bonded in a tetrahedral geometry to four equivalent I(1) atoms. All Mn(1)-I(1) bond lengths are 2.69 Å. There are two inequivalent I sites. In the first I site, I(1) is bonded in a 6-coordinate geometry to two equivalent Cs(2), three equivalent Cs(1), and one Mn(1) atom. In the second I site, I(2) is bonded to two equivalent Cs(2) and four equivalent Cs(1) atoms to form corner-sharing ICs6 octahedra. The corner-sharing octahedral tilt angles range from 0-41°.