DOE OSTI2020
Pr2B12O27Br2 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are two inequivalent Pr4+ sites. In the first Pr4+ site, Pr4+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pr–O bond distances ranging from 2.27–2.74 Å. In the second Pr4+ site, Pr4+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pr–O bond distances ranging from 2.26–2.76 Å. There are twelve inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.36–1.38 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.36 Å) and two longer (1.38 Å) B–O bond length. In the third B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. All B–O bond lengths are 1.38 Å. In the fourth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.37 Å) and two longer (1.38 Å) B–O bond length. In the fifth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.43–1.53 Å. In the sixth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.43–1.53 Å. In the seventh B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.42–1.53 Å. In the eighth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.41–1.53 Å. In the ninth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.37 Å) and one longer (1.38 Å) B–O bond length. In the tenth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.37 Å) and two longer (1.38 Å) B–O bond length. In the eleventh B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.43–1.50 Å. In the twelfth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.50 Å. There are twenty-seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr4+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one Pr4+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Pr4+ and one Br5+ atom. The O–Br bond length is 1.69 Å. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to one Pr4+ and one Br5+ atom. The O–Br bond length is 1.75 Å. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the eleventh O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the twelfth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the thirteenth O2- site, O2- is bonded in a trigonal planar geometry to three B3+ atoms. In the fourteenth O2- site, O2- is bonded in a trigonal planar geometry to three B3+ atoms. In the fifteenth O2- site, O2- is bonded in a single-bond geometry to one B3+ atom. In the sixteenth O2- site, O2- is bonded in a single-bond geometry to one B3+ atom. In the seventeenth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the eighteenth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the nineteenth O2- site, O2- is bonded in a bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the twentieth O2- site, O2- is bonded in a bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the twenty-first O2- site, O2- is bonded in a 2-coordinate geometry to one Pr4+ and one B3+ atom. In the twenty-second O2- site, O2- is bonded in a 2-coordinate geometry to one Pr4+ and one B3+ atom. In the twenty-third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the twenty-fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the twenty-fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the twenty-sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Pr4+ and two B3+ atoms. In the twenty-seventh O2- site, O2- is bonded in a single-bond geometry to one Br5+ atom. The O–Br bond length is 1.67 Å. There are two inequivalent Br5+ sites. In the first Br5+ site, Br5+ is bonded in a bent 120 degrees geometry to two O2- atoms. In the second Br5+ site, Br5+ is bonded in a single-bond geometry to one O2- atom.