Materials Data on Na4Eu2GeAs4 by Materials Project

Abstract

Na4Eu2GeAs4 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five As3- atoms. There are a spread of Na–As bond distances ranging from 3.14–3.34 Å. In the second Na1+ site, Na1+ is bonded to four As3- atoms to form distorted NaAs4 tetrahedra that share corners with two equivalent GeAs4 tetrahedra, corners with six NaAs4 tetrahedra, corners with two equivalent NaAs4 trigonal pyramids, and an edgeedge with one GeAs4 tetrahedra. There are a spread of Na–As bond distances ranging from 2.96–3.17 Å. In the third Na1+ site, Na1+ is bonded to four As3- atoms to form distorted NaAs4 trigonal pyramids that share corners with two equivalent GeAs4 tetrahedra, corners with six NaAs4 tetrahedra, corners with two equivalent NaAs4 trigonal pyramids, and an edgeedge with one GeAs4 tetrahedra. There are a spread of Na–As bond distances ranging from 2.94–3.16 Å. In the fourth Na1+ site, Na1+ is bonded to four As3- atoms to form distorted NaAs4 tetrahedra that share corners with two equivalent GeAs4 tetrahedra, corners with four equivalent NaAs4 tetrahedra, corners with four equivalent NaAs4 trigonal pyramids, and an edgeedge with one GeAs4 tetrahedra. There are a spread of Na–As bond distances ranging from 2.99–3.18 Å. There are two inequivalent Eu2+ sites. In the first Eu2+ site, Eu2+ is bonded in a 6-coordinate geometry to six As3- atoms. There are a spread of Eu–As bond distances ranging from 3.12–3.60 Å. In the second Eu2+ site, Eu2+ is bonded in a 6-coordinate geometry to six As3- atoms. There are a spread of Eu–As bond distances ranging from 3.11–3.53 Å. Ge4+ is bonded to four As3- atoms to form GeAs4 tetrahedra that share corners with four NaAs4 tetrahedra, corners with two equivalent NaAs4 trigonal pyramids, edges with two NaAs4 tetrahedra, and an edgeedge with one NaAs4 trigonal pyramid. There are a spread of Ge–As bond distances ranging from 2.46–2.54 Å. There are four inequivalent As3- sites. In the first As3- site, As3- is bonded in a 8-coordinate geometry to five Na1+, two equivalent Eu2+, and one Ge4+ atom. In the second As3- site, As3- is bonded in a 7-coordinate geometry to four Na1+, four Eu2+, and one Ge4+ atom. In the third As3- site, As3- is bonded in a 8-coordinate geometry to four Na1+, three Eu2+, and one Ge4+ atom. In the fourth As3- site, As3- is bonded in a 8-coordinate geometry to four Na1+, three Eu2+, and one Ge4+ atom.