Materials Data on BaMg4Si3 by Materials Project
BaMg4Si3 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ba is bonded in a 8-coordinate geometry to eight equivalent Mg and eight equivalent Si atoms. All Ba–Mg bond lengths are 3.58 Å. All Ba–Si bond lengths are 3.49 Å. Mg is bonded to two equivalent Ba and four Si atoms to form a mixture of distorted edge, corner, and face-sharing MgBa2Si4 tetrahedra. There are two shorter (2.76 Å) and two longer (2.80 Å) Mg–Si bond lengths. There are two inequivalent Si sites. In the first Si site, Si is bonded in a body-centered cubic geometry to eight equivalent Mg atoms. In the second Si site, Si is bonded in a 9-coordinate geometry to four equivalent Ba, four equivalent Mg, and one Si atom. The Si–Si bond length is 2.46 Å.