DOE OSTI2020
Li2TcO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with four TcO6 octahedra, edges with four TcO6 octahedra, and edges with eight LiO6 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. There are a spread of Li–O bond distances ranging from 2.03–2.14 Å. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with six LiO6 octahedra, edges with six LiO6 octahedra, and edges with six TcO6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are a spread of Li–O bond distances ranging from 2.00–2.02 Å. In the third Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with four TcO6 octahedra, edges with four TcO6 octahedra, and edges with eight LiO6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. There are a spread of Li–O bond distances ranging from 2.06–2.11 Å. There are two inequivalent Tc4+ sites. In the first Tc4+ site, Tc4+ is bonded to six O2- atoms to form TcO6 octahedra that share corners with six LiO6 octahedra, edges with three equivalent TcO6 octahedra, and edges with nine LiO6 octahedra. The corner-sharing octahedra tilt angles range from 2–4°. There are four shorter (2.05 Å) and two longer (2.06 Å) Tc–O bond lengths. In the second Tc4+ site, Tc4+ is bonded to six O2- atoms to form TcO6 octahedra that share corners with six LiO6 octahedra, edges with three equivalent TcO6 octahedra, and edges with nine LiO6 octahedra. The corner-sharing octahedra tilt angles range from 2–3°. All Tc–O bond lengths are 2.05 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four Li1+ and two Tc4+ atoms to form a mixture of edge and corner-sharing OLi4Tc2 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the second O2- site, O2- is bonded to four Li1+ and two Tc4+ atoms to form a mixture of edge and corner-sharing OLi4Tc2 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the third O2- site, O2- is bonded to four Li1+ and two Tc4+ atoms to form a mixture of edge and corner-sharing OLi4Tc2 octahedra. The corner-sharing octahedra tilt angles range from 0–3°.