BaTiSe3 crystallizes in the hexagonal P6_3/mmc space group. Ba(1) is bonded to twelve equivalent Se(1) atoms to form BaSe12 cuboctahedra that share corners with six equivalent Ba(1)Se12 cuboctahedra, corners with six equivalent Ti(1)Se6 octahedra, faces with eight equivalent Ba(1)Se12 cuboctahedra, and faces with six equivalent Ti(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 20°. Ti(1) is bonded to six equivalent Se(1) atoms to form TiSe6 octahedra that share corners with six equivalent Ba(1)Se12 cuboctahedra, faces with six equivalent Ba(1)Se12 cuboctahedra, and faces with two equivalent Ti(1)Se6 octahedra. Se(1) is bonded to four equivalent Ba(1) and two equivalent Ti(1) atoms to form a mixture of distorted corner, edge, and face-sharing SeBa4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°.
BaTiSe3 crystallizes in the hexagonal P6_3/mmc space group. Ba(1) is bonded to twelve equivalent Se(1) atoms to form BaSe12 cuboctahedra that share corners with six equivalent Ba(1)Se12 cuboctahedra, corners with six equivalent Ti(1)Se6 octahedra, faces with eight equivalent Ba(1)Se12 cuboctahedra, and faces with six equivalent Ti(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 20°. There are six shorter (3.55 Å) and six longer (3.65 Å) Ba(1)-Se(1) bond lengths. Ti(1) is bonded to six equivalent Se(1) atoms to form TiSe6 octahedra that share corners with six equivalent Ba(1)Se12 cuboctahedra, faces with six equivalent Ba(1)Se12 cuboctahedra, and faces with two equivalent Ti(1)Se6 octahedra. All Ti(1)-Se(1) bond lengths are 2.56 Å. Se(1) is bonded to four equivalent Ba(1) and two equivalent Ti(1) atoms to form a mixture of distorted corner, edge, and face-sharing SeBa4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°.