Rb4SiO4 crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), two equivalent O(2), and three equivalent O(1) atoms. In the second Rb site, Rb(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. In the third Rb site, Rb(3) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(4) atoms. In the fourth Rb site, Rb(4) is bonded in a 5-coordinate geometry to one O(2), two equivalent O(3), and two equivalent O(4) atoms. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Rb(2), three equivalent Rb(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Rb(2), one Rb(3), one Rb(4), two equivalent Rb(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(2), one Rb(3), two equivalent Rb(4), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(2), two equivalent Rb(3), two equivalent Rb(4), and one Si(1) atom.
Rb4SiO4 crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), two equivalent O(2), and three equivalent O(1) atoms. The Rb(1)-O(3) bond length is 3.18 Å. The Rb(1)-O(4) bond length is 3.35 Å. There is one shorter (2.94 Å) and one longer (3.27 Å) Rb(1)-O(2) bond length. There are a spread of Rb(1)-O(1) bond distances ranging from 2.75-3.08 Å. In the second Rb site, Rb(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. The Rb(2)-O(2) bond length is 2.83 Å. The Rb(2)-O(3) bond length is 2.83 Å. The Rb(2)-O(4) bond length is 3.27 Å. There is one shorter (2.77 Å) and one longer (2.82 Å) Rb(2)-O(1) bond length. In the third Rb site, Rb(3) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(4) atoms. The Rb(3)-O(2) bond length is 2.70 Å. The Rb(3)-O(3) bond length is 2.90 Å. There is one shorter (2.71 Å) and one longer (2.84 Å) Rb(3)-O(4) bond length. In the fourth Rb site, Rb(4) is bonded in a 5-coordinate geometry to one O(2), two equivalent O(3), and two equivalent O(4) atoms. The Rb(4)-O(2) bond length is 2.84 Å. There is one shorter (2.85 Å) and one longer (2.98 Å) Rb(4)-O(3) bond length. There is one shorter (2.80 Å) and one longer (2.87 Å) Rb(4)-O(4) bond length. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Si(1)-O(1) bond length is 1.65 Å. The Si(1)-O(2) bond length is 1.66 Å. The Si(1)-O(3) bond length is 1.67 Å. The Si(1)-O(4) bond length is 1.66 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Rb(2), three equivalent Rb(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Rb(2), one Rb(3), one Rb(4), two equivalent Rb(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(2), one Rb(3), two equivalent Rb(4), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(2), two equivalent Rb(3), two equivalent Rb(4), and one Si(1) atom.