TcAs3 is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. Tc(1) is bonded to four equivalent As(2) and eight equivalent As(1) atoms to form distorted TcAs12 cuboctahedra that share corners with four equivalent Tc(1)As12 cuboctahedra, corners with eight equivalent As(2)Tc4As8 cuboctahedra, edges with eight equivalent Tc(1)As12 cuboctahedra, faces with four equivalent Tc(1)As12 cuboctahedra, and faces with six equivalent As(2)Tc4As8 cuboctahedra. There are two inequivalent As sites. In the first As site, As(1) is bonded in a distorted body-centered cubic geometry to four equivalent Tc(1) and four equivalent As(2) atoms. In the second As site, As(2) is bonded to four equivalent Tc(1) and eight equivalent As(1) atoms to form AsTc4As8 cuboctahedra that share corners with four equivalent As(2)Tc4As8 cuboctahedra, corners with eight equivalent Tc(1)As12 cuboctahedra, edges with eight equivalent As(2)Tc4As8 cuboctahedra, faces with four equivalent As(2)Tc4As8 cuboctahedra, and faces with six equivalent Tc(1)As12 cuboctahedra.
TcAs3 is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. Tc(1) is bonded to four equivalent As(2) and eight equivalent As(1) atoms to form distorted TcAs12 cuboctahedra that share corners with four equivalent Tc(1)As12 cuboctahedra, corners with eight equivalent As(2)Tc4As8 cuboctahedra, edges with eight equivalent Tc(1)As12 cuboctahedra, faces with four equivalent Tc(1)As12 cuboctahedra, and faces with six equivalent As(2)Tc4As8 cuboctahedra. All Tc(1)-As(2) bond lengths are 3.11 Å. All Tc(1)-As(1) bond lengths are 2.79 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded in a distorted body-centered cubic geometry to four equivalent Tc(1) and four equivalent As(2) atoms. All As(1)-As(2) bond lengths are 2.79 Å. In the second As site, As(2) is bonded to four equivalent Tc(1) and eight equivalent As(1) atoms to form AsTc4As8 cuboctahedra that share corners with four equivalent As(2)Tc4As8 cuboctahedra, corners with eight equivalent Tc(1)As12 cuboctahedra, edges with eight equivalent As(2)Tc4As8 cuboctahedra, faces with four equivalent As(2)Tc4As8 cuboctahedra, and faces with six equivalent Tc(1)As12 cuboctahedra.