Mg2Ti crystallizes in the trigonal R32 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2); six equivalent Mg(1); and four Ti(1,1,1) atoms to form MgMg8Ti4 cuboctahedra that share corners with eighteen Mg(1,1,1)Mg8Ti4 cuboctahedra; edges with four equivalent Mg(2)Mg6Ti6 cuboctahedra; edges with six equivalent Mg(1)Mg8Ti4 cuboctahedra; edges with eight Ti(1,1,1)Mg9Ti3 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with eight equivalent Mg(1)Mg8Ti4 cuboctahedra; and faces with eight Ti(1,1,1)Mg9Ti3 cuboctahedra. In the second Mg site, Mg(2) is bonded to six Mg(1,1) and six Ti(1,1) atoms to form MgMg6Ti6 cuboctahedra that share corners with six equivalent Mg(2)Mg6Ti6 cuboctahedra; corners with twelve Ti(1,1,1)Mg9Ti3 cuboctahedra; edges with six equivalent Mg(2)Mg6Ti6 cuboctahedra; edges with twelve Mg(1,1)Mg8Ti4 cuboctahedra; faces with eight Ti(1,1,1,1)Mg9Ti3 cuboctahedra; and faces with twelve Mg(1,1)Mg8Ti4 cuboctahedra. In the third Mg site, Mg(1) is bonded to two equivalent Mg(2); six equivalent Mg(1); and four Ti(1,1,1) atoms to form MgMg8Ti4 cuboctahedra that share corners with eighteen Mg(1,1)Mg8Ti4 cuboctahedra; edges with four equivalent Mg(2)Mg6Ti6 cuboctahedra; edges with six equivalent Mg(1)Mg8Ti4 cuboctahedra; edges with eight Ti(1,1,1)Mg9Ti3 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with eight equivalent Mg(1)Mg8Ti4 cuboctahedra; and faces with eight Ti(1,1,1)Mg9Ti3 cuboctahedra. In the fourth Mg site, Mg(1) is bonded to two equivalent Mg(2); six equivalent Mg(1); and four Ti(1,1,1,1) atoms to form MgMg8Ti4 cuboctahedra that share corners with eighteen Mg(1,1)Mg8Ti4 cuboctahedra; edges with four equivalent Mg(2)Mg6Ti6 cuboctahedra; edges with six equivalent Mg(1)Mg8Ti4 cuboctahedra; edges with eight Ti(1,1,1,1)Mg9Ti3 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with eight equivalent Mg(1)Mg8Ti4 cuboctahedra; and faces with eight Ti(1,1,1,1)Mg9Ti3 cuboctahedra. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to three equivalent Mg(2); six Mg(1,1); and three equivalent Ti(1) atoms to form TiMg9Ti3 cuboctahedra that share corners with six equivalent Mg(2)Mg6Ti6 cuboctahedra; corners with twelve Ti(1,1,1)Mg9Ti3 cuboctahedra; edges with six equivalent Ti(1)Mg9Ti3 cuboctahedra; edges with twelve Mg(1,1)Mg8Ti4 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with four Ti(1,1)Mg9Ti3 cuboctahedra; and faces with twelve Mg(1,1)Mg8Ti4 cuboctahedra. In the second Ti site, Ti(1) is bonded to three equivalent Mg(2); six Mg(1,1); and three equivalent Ti(1) atoms to form TiMg9Ti3 cuboctahedra that share corners with six equivalent Mg(2)Mg6Ti6 cuboctahedra; corners with twelve Ti(1,1,1)Mg9Ti3 cuboctahedra; edges with six equivalent Ti(1)Mg9Ti3 cuboctahedra; edges with twelve Mg(1,1)Mg8Ti4 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with four Ti(1,1)Mg9Ti3 cuboctahedra; and faces with twelve Mg(1,1)Mg8Ti4 cuboctahedra. In the third Ti site, Ti(1) is bonded to three equivalent Mg(2); six Mg(1,1); and three equivalent Ti(1) atoms to form TiMg9Ti3 cuboctahedra that share corners with six equivalent Mg(2)Mg6Ti6 cuboctahedra; corners with twelve Ti(1,1,1)Mg9Ti3 cuboctahedra; edges with six equivalent Ti(1)Mg9Ti3 cuboctahedra; edges with twelve Mg(1,1)Mg8Ti4 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with four Ti(1,1)Mg9Ti3 cuboctahedra; and faces with twelve Mg(1,1)Mg8Ti4 cuboctahedra. In the fourth Ti site, Ti(1) is bonded to three equivalent Mg(2); six Mg(1,1,1); and three equivalent Ti(1) atoms to form TiMg9Ti3 cuboctahedra that share corners with six equivalent Mg(2)Mg6Ti6 cuboctahedra; corners with twelve Ti(1,1,1)Mg9Ti3 cuboctahedra; edges with six equivalent Ti(1)Mg9Ti3 cuboctahedra; edges with twelve Mg(1,1,1)Mg8Ti4 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with four equivalent Ti(1)Mg9Ti3 cuboctahedra; and faces with twelve Mg(1,1,1)Mg8Ti4 cuboctahedra.
Mg2Ti crystallizes in the trigonal R32 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2); six equivalent Mg(1); and four Ti(1,1,1) atoms to form MgMg8Ti4 cuboctahedra that share corners with eighteen Mg(1,1,1)Mg8Ti4 cuboctahedra; edges with four equivalent Mg(2)Mg6Ti6 cuboctahedra; edges with six equivalent Mg(1)Mg8Ti4 cuboctahedra; edges with eight Ti(1,1,1)Mg9Ti3 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with eight equivalent Mg(1)Mg8Ti4 cuboctahedra; and faces with eight Ti(1,1,1)Mg9Ti3 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.12 Å. There are two shorter (3.04 Å) and four longer (3.07 Å) Mg(1)-Mg(1) bond lengths. There are two shorter (3.11 Å) and two longer (3.12 Å) Mg(1)-Ti(1,1,1) bond lengths. In the second Mg site, Mg(2) is bonded to six Mg(1,1) and six Ti(1,1) atoms to form MgMg6Ti6 cuboctahedra that share corners with six equivalent Mg(2)Mg6Ti6 cuboctahedra; corners with twelve Ti(1,1,1)Mg9Ti3 cuboctahedra; edges with six equivalent Mg(2)Mg6Ti6 cuboctahedra; edges with twelve Mg(1,1)Mg8Ti4 cuboctahedra; faces with eight Ti(1,1,1,1)Mg9Ti3 cuboctahedra; and faces with twelve Mg(1,1)Mg8Ti4 cuboctahedra. The Mg(2)-Mg(1) bond length is 3.12 Å. All Mg(2)-Ti(1,1) bond lengths are 3.06 Å. In the third Mg site, Mg(1) is bonded to two equivalent Mg(2); six equivalent Mg(1); and four Ti(1,1,1) atoms to form MgMg8Ti4 cuboctahedra that share corners with eighteen Mg(1,1)Mg8Ti4 cuboctahedra; edges with four equivalent Mg(2)Mg6Ti6 cuboctahedra; edges with six equivalent Mg(1)Mg8Ti4 cuboctahedra; edges with eight Ti(1,1,1)Mg9Ti3 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with eight equivalent Mg(1)Mg8Ti4 cuboctahedra; and faces with eight Ti(1,1,1)Mg9Ti3 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.12 Å. There are two shorter (3.04 Å) and four longer (3.07 Å) Mg(1)-Mg(1) bond lengths. There are two shorter (3.11 Å) and two longer (3.12 Å) Mg(1)-Ti(1,1,1) bond lengths. In the fourth Mg site, Mg(1) is bonded to two equivalent Mg(2); six equivalent Mg(1); and four Ti(1,1,1,1) atoms to form MgMg8Ti4 cuboctahedra that share corners with eighteen Mg(1,1)Mg8Ti4 cuboctahedra; edges with four equivalent Mg(2)Mg6Ti6 cuboctahedra; edges with six equivalent Mg(1)Mg8Ti4 cuboctahedra; edges with eight Ti(1,1,1,1)Mg9Ti3 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with eight equivalent Mg(1)Mg8Ti4 cuboctahedra; and faces with eight Ti(1,1,1,1)Mg9Ti3 cuboctahedra. There are two shorter (3.04 Å) and four longer (3.07 Å) Mg(1)-Mg(1) bond lengths. There are two shorter (3.11 Å) and two longer (3.12 Å) Mg(1)-Ti(1,1,1,1) bond lengths. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to three equivalent Mg(2); six Mg(1,1); and three equivalent Ti(1) atoms to form TiMg9Ti3 cuboctahedra that share corners with six equivalent Mg(2)Mg6Ti6 cuboctahedra; corners with twelve Ti(1,1,1)Mg9Ti3 cuboctahedra; edges with six equivalent Ti(1)Mg9Ti3 cuboctahedra; edges with twelve Mg(1,1)Mg8Ti4 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with four Ti(1,1)Mg9Ti3 cuboctahedra; and faces with twelve Mg(1,1)Mg8Ti4 cuboctahedra. All Ti(1)-Ti(1) bond lengths are 3.06 Å. In the second Ti site, Ti(1) is bonded to three equivalent Mg(2); six Mg(1,1); and three equivalent Ti(1) atoms to form TiMg9Ti3 cuboctahedra that share corners with six equivalent Mg(2)Mg6Ti6 cuboctahedra; corners with twelve Ti(1,1,1)Mg9Ti3 cuboctahedra; edges with six equivalent Ti(1)Mg9Ti3 cuboctahedra; edges with twelve Mg(1,1)Mg8Ti4 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with four Ti(1,1)Mg9Ti3 cuboctahedra; and faces with twelve Mg(1,1)Mg8Ti4 cuboctahedra. In the third Ti site, Ti(1) is bonded to three equivalent Mg(2); six Mg(1,1); and three equivalent Ti(1) atoms to form TiMg9Ti3 cuboctahedra that share corners with six equivalent Mg(2)Mg6Ti6 cuboctahedra; corners with twelve Ti(1,1,1)Mg9Ti3 cuboctahedra; edges with six equivalent Ti(1)Mg9Ti3 cuboctahedra; edges with twelve Mg(1,1)Mg8Ti4 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with four Ti(1,1)Mg9Ti3 cuboctahedra; and faces with twelve Mg(1,1)Mg8Ti4 cuboctahedra. All Ti(1)-Mg(2) bond lengths are 3.06 Å. All Ti(1)-Ti(1) bond lengths are 3.06 Å. In the fourth Ti site, Ti(1) is bonded to three equivalent Mg(2); six Mg(1,1,1); and three equivalent Ti(1) atoms to form TiMg9Ti3 cuboctahedra that share corners with six equivalent Mg(2)Mg6Ti6 cuboctahedra; corners with twelve Ti(1,1,1)Mg9Ti3 cuboctahedra; edges with six equivalent Ti(1)Mg9Ti3 cuboctahedra; edges with twelve Mg(1,1,1)Mg8Ti4 cuboctahedra; faces with four equivalent Mg(2)Mg6Ti6 cuboctahedra; faces with four equivalent Ti(1)Mg9Ti3 cuboctahedra; and faces with twelve Mg(1,1,1)Mg8Ti4 cuboctahedra. All Ti(1)-Mg(2) bond lengths are 3.06 Å. There are two shorter (3.11 Å) and two longer (3.12 Å) Ti(1)-Mg(1) bond lengths. All Ti(1)-Ti(1) bond lengths are 3.06 Å.