RbEuSiS4 crystallizes in the orthorhombic P2_12_12_1 space group. Rb(1) is bonded in a 8-coordinate geometry to one S(4), two equivalent S(1), two equivalent S(2), and three equivalent S(3) atoms. Eu(1) is bonded in a 7-coordinate geometry to one S(3), two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms. Si(1) is bonded in a tetrahedral geometry to one S(1), one S(2), one S(3), and one S(4) atom. There are four inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Rb(1), two equivalent Eu(1), and one Si(1) atom. In the second S site, S(2) is bonded in a 5-coordinate geometry to two equivalent Rb(1), two equivalent Eu(1), and one Si(1) atom. In the third S site, S(3) is bonded to three equivalent Rb(1), one Eu(1), and one Si(1) atom to form distorted corner-sharing SRb3EuSi trigonal bipyramids. In the fourth S site, S(4) is bonded in a distorted see-saw-like geometry to one Rb(1), two equivalent Eu(1), and one Si(1) atom.
RbEuSiS4 crystallizes in the orthorhombic P2_12_12_1 space group. Rb(1) is bonded in a 8-coordinate geometry to one S(4), two equivalent S(1), two equivalent S(2), and three equivalent S(3) atoms. The Rb(1)-S(4) bond length is 3.37 Å. There is one shorter (3.48 Å) and one longer (3.67 Å) Rb(1)-S(1) bond length. There is one shorter (3.56 Å) and one longer (3.59 Å) Rb(1)-S(2) bond length. There are a spread of Rb(1)-S(3) bond distances ranging from 3.47-3.54 Å. Eu(1) is bonded in a 7-coordinate geometry to one S(3), two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms. The Eu(1)-S(3) bond length is 2.86 Å. There is one shorter (2.91 Å) and one longer (2.96 Å) Eu(1)-S(1) bond length. There is one shorter (2.89 Å) and one longer (2.92 Å) Eu(1)-S(2) bond length. There is one shorter (2.85 Å) and one longer (3.05 Å) Eu(1)-S(4) bond length. Si(1) is bonded in a tetrahedral geometry to one S(1), one S(2), one S(3), and one S(4) atom. The Si(1)-S(1) bond length is 2.13 Å. The Si(1)-S(2) bond length is 2.13 Å. The Si(1)-S(3) bond length is 2.10 Å. The Si(1)-S(4) bond length is 2.12 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Rb(1), two equivalent Eu(1), and one Si(1) atom. In the second S site, S(2) is bonded in a 5-coordinate geometry to two equivalent Rb(1), two equivalent Eu(1), and one Si(1) atom. In the third S site, S(3) is bonded to three equivalent Rb(1), one Eu(1), and one Si(1) atom to form distorted corner-sharing SRb3EuSi trigonal bipyramids. In the fourth S site, S(4) is bonded in a distorted see-saw-like geometry to one Rb(1), two equivalent Eu(1), and one Si(1) atom.