RbMgPO4 crystallizes in the orthorhombic Pnma space group. Rb(1) is bonded in a 4-coordinate geometry to four equivalent O(3) atoms. Mg(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form MgO4 tetrahedra that share corners with four equivalent P(1)O4 tetrahedra. P(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Mg(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Mg(1) and one P(1) atom. In the second O site, O(2) is bonded in a linear geometry to one Mg(1) and one P(1) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent Rb(1), one Mg(1), and one P(1) atom.
RbMgPO4 crystallizes in the orthorhombic Pnma space group. Rb(1) is bonded in a 4-coordinate geometry to four equivalent O(3) atoms. There are two shorter (3.04 Å) and two longer (3.06 Å) Rb(1)-O(3) bond lengths. Mg(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form MgO4 tetrahedra that share corners with four equivalent P(1)O4 tetrahedra. The Mg(1)-O(1) bond length is 1.92 Å. The Mg(1)-O(2) bond length is 1.92 Å. Both Mg(1)-O(3) bond lengths are 1.95 Å. P(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Mg(1)O4 tetrahedra. The P(1)-O(1) bond length is 1.54 Å. The P(1)-O(2) bond length is 1.54 Å. Both P(1)-O(3) bond lengths are 1.56 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Mg(1) and one P(1) atom. In the second O site, O(2) is bonded in a linear geometry to one Mg(1) and one P(1) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent Rb(1), one Mg(1), and one P(1) atom.