Materials Data on SrCaSi4 by Materials Project
SrCaSi4 is hexagonal omega structure-derived structured and crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. Sr is bonded to twelve Si atoms to form SrSi12 cuboctahedra that share edges with four equivalent SrSi12 cuboctahedra, edges with eight equivalent CaSi12 cuboctahedra, faces with four equivalent SrSi12 cuboctahedra, and faces with four equivalent CaSi12 cuboctahedra. There are four shorter (3.16 Å) and eight longer (3.30 Å) Sr–Si bond lengths. Ca is bonded to twelve Si atoms to form CaSi12 cuboctahedra that share edges with four equivalent CaSi12 cuboctahedra, edges with eight equivalent SrSi12 cuboctahedra, faces with four equivalent SrSi12 cuboctahedra, and faces with four equivalent CaSi12 cuboctahedra. There are four shorter (3.14 Å) and eight longer (3.29 Å) Ca–Si bond lengths. There are four inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to two equivalent Sr, four equivalent Ca, and three Si atoms. There are one shorter (2.29 Å) and two longer (2.45 Å) Si–Si bond lengths. In the second Si site, Si is bonded in a 9-coordinate geometry to four equivalent Sr, two equivalent Ca, and three Si atoms. The Si–Si bond length is 2.34 Å. In the third Si site, Si is bonded in a 9-coordinate geometry to two equivalent Sr, four equivalent Ca, and three Si atoms. Both Si–Sr bond lengths are 3.16 Å. Both Si–Si bond lengths are 2.45 Å. In the fourth Si site, Si is bonded in a 9-coordinate geometry to four equivalent Sr, two equivalent Ca, and three Si atoms. The Si–Si bond length is 2.34 Å.