SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
PbSe2 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Pb4+ is bonded in a 8-coordinate geometry to eight equivalent Se2- atoms. All Pb–Se bond lengths are 3.22 Å. Se2- is bonded in a 5-coordinate geometry to four equivalent Pb4+ and one Se2- atom. The Se–Se bond length is 2.41 Å.
SiPb2Se4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Pb–Se bond distances ranging from 2.90–3.67 Å. In the second Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Pb–Se bond distances ranging from 2.95–3.74 Å. Si4+ is bonded in a tetrahedral geometry to four Se2- atoms. There are three shorter (2.30 Å) and one longer (2.31 Å) Si–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted single-bond geometry to three Pb2+ and one Si4+ atom. In the second Se2- site, Se2- is bonded in a distorted single-bond geometry to four Pb2+ and one Si4+ atom. In the third Se2- site, Se2- is bonded in a distorted single-bond geometry to four Pb2+ and one Si4+ atom. In the fourth Se2- site, Se2- is bonded in a distorted single-bond geometry to three Pb2+ and one Si4+ atom.