DOE OSTI2020
Ti4ZnAl11 crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. there are four inequivalent Ti sites. In the first Ti site, Ti is bonded to twelve Al atoms to form TiAl12 cuboctahedra that share corners with four equivalent ZnTi4Al8 cuboctahedra, corners with eight TiAl12 cuboctahedra, edges with four equivalent TiAl8Zn4 cuboctahedra, edges with twenty AlTi4Al6Zn2 cuboctahedra, a faceface with one ZnTi4Al8 cuboctahedra, faces with five TiAl12 cuboctahedra, and faces with twelve AlTi4Al8 cuboctahedra. There are eight shorter (2.76 Å) and four longer (2.97 Å) Ti–Al bond lengths. In the second Ti site, Ti is bonded to twelve Al atoms to form TiAl12 cuboctahedra that share corners with four equivalent AlTi4Al8 cuboctahedra, corners with eight TiAl12 cuboctahedra, edges with four equivalent TiAl12 cuboctahedra, edges with four equivalent ZnTi4Al8 cuboctahedra, edges with sixteen AlTi4Al8 cuboctahedra, faces with five TiAl12 cuboctahedra, and faces with thirteen AlTi4Al6Zn2 cuboctahedra. There are a spread of Ti–Al bond distances ranging from 2.76–2.94 Å. In the third Ti site, Ti is bonded to four equivalent Zn and eight Al atoms to form TiAl8Zn4 cuboctahedra that share corners with four equivalent AlTi4Al8 cuboctahedra, corners with eight TiAl12 cuboctahedra, edges with four equivalent TiAl12 cuboctahedra, edges with twenty AlTi4Al6Zn2 cuboctahedra, faces with four equivalent ZnTi4Al8 cuboctahedra, faces with five TiAl12 cuboctahedra, and faces with nine AlTi4Al6Zn2 cuboctahedra. All Ti–Zn bond lengths are 2.76 Å. There are four shorter (2.75 Å) and four longer (2.90 Å) Ti–Al bond lengths. In the fourth Ti site, Ti is bonded to twelve Al atoms to form TiAl12 cuboctahedra that share corners with four equivalent AlTi4Al8 cuboctahedra, corners with eight TiAl12 cuboctahedra, edges with four equivalent TiAl12 cuboctahedra, edges with twenty AlTi4Al8 cuboctahedra, faces with five TiAl12 cuboctahedra, and faces with thirteen AlTi4Al8 cuboctahedra. There are a spread of Ti–Al bond distances ranging from 2.76–2.93 Å. Zn is bonded to four equivalent Ti and eight Al atoms to form ZnTi4Al8 cuboctahedra that share corners with four equivalent TiAl12 cuboctahedra, corners with four equivalent ZnTi4Al8 cuboctahedra, corners with four equivalent AlTi4Al8 cuboctahedra, edges with four equivalent TiAl12 cuboctahedra, edges with twenty AlTi4Al6Zn2 cuboctahedra, faces with four equivalent ZnTi4Al8 cuboctahedra, faces with five TiAl12 cuboctahedra, and faces with nine AlTi4Al6Zn2 cuboctahedra. There are four shorter (2.80 Å) and four longer (2.84 Å) Zn–Al bond lengths. There are seven inequivalent Al sites. In the first Al site, Al is bonded to four Ti, two equivalent Zn, and six Al atoms to form AlTi4Al6Zn2 cuboctahedra that share corners with twelve AlTi4Al6Zn2 cuboctahedra, edges with four equivalent ZnTi4Al8 cuboctahedra, edges with eight TiAl12 cuboctahedra, edges with twelve AlTi4Al6Zn2 cuboctahedra, faces with two equivalent ZnTi4Al8 cuboctahedra, faces with four TiAl12 cuboctahedra, and faces with twelve AlTi4Al6Zn2 cuboctahedra. There are four shorter (2.76 Å) and two longer (2.87 Å) Al–Al bond lengths. In the second Al site, Al is bonded to four Ti and eight Al atoms to form AlTi4Al8 cuboctahedra that share corners with twelve AlTi4Al6Zn2 cuboctahedra, edges with eight TiAl12 cuboctahedra, edges with sixteen AlTi4Al6Zn2 cuboctahedra, faces with four TiAl12 cuboctahedra, and faces with fourteen AlTi4Al8 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.76–2.88 Å. In the third Al site, Al is bonded to four Ti, two equivalent Zn, and six Al atoms to form AlTi4Al6Zn2 cuboctahedra that share corners with twelve AlTi4Al6Zn2 cuboctahedra, edges with four equivalent ZnTi4Al8 cuboctahedra, edges with eight TiAl12 cuboctahedra, edges with twelve AlTi4Al6Zn2 cuboctahedra, faces with two equivalent ZnTi4Al8 cuboctahedra, faces with four TiAl12 cuboctahedra, and faces with twelve AlTi4Al6Zn2 cuboctahedra. There are four shorter (2.76 Å) and two longer (2.85 Å) Al–Al bond lengths. In the fourth Al site, Al is bonded to four Ti and eight Al atoms to form AlTi4Al8 cuboctahedra that share corners with twelve AlTi4Al8 cuboctahedra, edges with eight TiAl12 cuboctahedra, edges with sixteen AlTi4Al6Zn2 cuboctahedra, faces with four TiAl12 cuboctahedra, and faces with fourteen AlTi4Al6Zn2 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.76–2.86 Å. In the fifth Al site, Al is bonded to four equivalent Ti and eight Al atoms to form AlTi4Al8 cuboctahedra that share corners with four equivalent TiAl12 cuboctahedra, corners with eight AlTi4Al8 cuboctahedra, edges with four equivalent TiAl12 cuboctahedra, edges with twenty AlTi4Al8 cuboctahedra, faces with five TiAl12 cuboctahedra, and faces with thirteen AlTi4Al8 cuboctahedra. In the sixth Al site, Al is bonded to four equivalent Ti and eight Al atoms to form AlTi4Al8 cuboctahedra that share corners with four equivalent TiAl8Zn4 cuboctahedra, corners with eight AlTi4Al8 cuboctahedra, edges with four equivalent TiAl12 cuboctahedra, edges with four equivalent ZnTi4Al8 cuboctahedra, edges with sixteen AlTi4Al6Zn2 cuboctahedra, faces with five TiAl12 cuboctahedra, and faces with thirteen AlTi4Al8 cuboctahedra. In the seventh Al site, Al is bonded to four equivalent Ti and eight Al atoms to form AlTi4Al8 cuboctahedra that share corners with four equivalent TiAl12 cuboctahedra, corners with four equivalent ZnTi4Al8 cuboctahedra, corners with four equivalent AlTi4Al8 cuboctahedra, edges with four equivalent TiAl8Zn4 cuboctahedra, edges with twenty AlTi4Al8 cuboctahedra, a faceface with one ZnTi4Al8 cuboctahedra, faces with five TiAl12 cuboctahedra, and faces with twelve AlTi4Al6Zn2 cuboctahedra.