Rb2PdSe16 crystallizes in the tetragonal P-4b2 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded to four equivalent Se(1), four equivalent Se(2), and four equivalent Se(4) atoms to form distorted RbSe12 cuboctahedra that share corners with four equivalent Pd(1)Rb2Se4 octahedra. The corner-sharing octahedral tilt angles are 19°. In the second Rb site, Rb(2) is bonded in a linear geometry to two equivalent Pd(1) atoms. Pd(1) is bonded to two equivalent Rb(2) and four equivalent Se(2) atoms to form PdRb2Se4 octahedra that share corners with four equivalent Rb(1)Se12 cuboctahedra and corners with two equivalent Pd(1)Rb2Se4 octahedra. The corner-sharing octahedra are not tilted. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to one Rb(1), one Se(1), and one Se(4) atom. In the second Se site, Se(2) is bonded in a 1-coordinate geometry to one Rb(1), one Pd(1), and one Se(3) atom. In the third Se site, Se(3) is bonded in a water-like geometry to one Se(2) and one Se(3) atom. In the fourth Se site, Se(4) is bonded in a 3-coordinate geometry to one Rb(1), one Se(1), and one Se(4) atom.
Rb2PdSe16 crystallizes in the tetragonal P-4b2 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded to four equivalent Se(1), four equivalent Se(2), and four equivalent Se(4) atoms to form distorted RbSe12 cuboctahedra that share corners with four equivalent Pd(1)Rb2Se4 octahedra. The corner-sharing octahedral tilt angles are 19°. All Rb(1)-Se(1) bond lengths are 3.93 Å. All Rb(1)-Se(2) bond lengths are 4.04 Å. All Rb(1)-Se(4) bond lengths are 3.93 Å. In the second Rb site, Rb(2) is bonded in a linear geometry to two equivalent Pd(1) atoms. Both Rb(2)-Pd(1) bond lengths are 3.52 Å. Pd(1) is bonded to two equivalent Rb(2) and four equivalent Se(2) atoms to form PdRb2Se4 octahedra that share corners with four equivalent Rb(1)Se12 cuboctahedra and corners with two equivalent Pd(1)Rb2Se4 octahedra. The corner-sharing octahedra are not tilted. All Pd(1)-Se(2) bond lengths are 2.45 Å. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to one Rb(1), one Se(1), and one Se(4) atom. The Se(1)-Se(1) bond length is 2.39 Å. The Se(1)-Se(4) bond length is 2.37 Å. In the second Se site, Se(2) is bonded in a 1-coordinate geometry to one Rb(1), one Pd(1), and one Se(3) atom. The Se(2)-Se(3) bond length is 2.36 Å. In the third Se site, Se(3) is bonded in a water-like geometry to one Se(2) and one Se(3) atom. The Se(3)-Se(3) bond length is 2.38 Å. In the fourth Se site, Se(4) is bonded in a 3-coordinate geometry to one Rb(1), one Se(1), and one Se(4) atom. The Se(4)-Se(4) bond length is 2.38 Å.