La(MgSi)2 crystallizes in the tetragonal P4/mmm space group. Mg(1) is bonded in a distorted square co-planar geometry to four equivalent Si(1) atoms. La(1) is bonded to eight equivalent Si(1) atoms to form a mixture of distorted face and edge-sharing LaSi8 hexagonal bipyramids. Si(1) is bonded in a 9-coordinate geometry to four equivalent Mg(1), four equivalent La(1), and one Si(1) atom.
La(MgSi)2 crystallizes in the tetragonal P4/mmm space group. Mg(1) is bonded in a distorted square co-planar geometry to four equivalent Si(1) atoms. All Mg(1)-Si(1) bond lengths are 2.78 Å. La(1) is bonded to eight equivalent Si(1) atoms to form a mixture of distorted face and edge-sharing LaSi8 hexagonal bipyramids. All La(1)-Si(1) bond lengths are 3.26 Å. Si(1) is bonded in a 9-coordinate geometry to four equivalent Mg(1), four equivalent La(1), and one Si(1) atom. The Si(1)-Si(1) bond length is 2.31 Å.