Materials Data on TcAs3 by Materials Project

Abstract

TcAs3 is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Tc1+ is bonded to twelve As+0.33- atoms to form distorted TcAs12 cuboctahedra that share corners with four equivalent TcAs12 cuboctahedra, corners with eight equivalent AsTc4As8 cuboctahedra, edges with eight equivalent TcAs12 cuboctahedra, faces with four equivalent TcAs12 cuboctahedra, and faces with six equivalent AsTc4As8 cuboctahedra. There are eight shorter (2.79 Å) and four longer (3.11 Å) Tc–As bond lengths. There are two inequivalent As+0.33- sites. In the first As+0.33- site, As+0.33- is bonded in a distorted body-centered cubic geometry to four equivalent Tc1+ and four equivalent As+0.33- atoms. All As–As bond lengths are 2.79 Å. In the second As+0.33- site, As+0.33- is bonded to four equivalent Tc1+ and eight equivalent As+0.33- atoms to form AsTc4As8 cuboctahedra that share corners with four equivalent AsTc4As8 cuboctahedra, corners with eight equivalent TcAs12 cuboctahedra, edges with eight equivalent AsTc4As8 cuboctahedra, faces with four equivalent AsTc4As8 cuboctahedra, and faces with six equivalent TcAs12 cuboctahedra.