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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on KNa(BH4)2 by Materials Project

NaK(BH4)2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. K1+ is bonded to twelve equivalent H+0.50+ atoms to form KH12 cuboctahedra that share edges with six equivalent KH12 cuboctahedra, edges with six equivalent NaH12 cuboctahedra, and edges with six equivalent BH4 tetrahedra. All K–H bond lengths are 2.79 Å. Na1+ is bonded to twelve H+0.50+ atoms to form distorted NaH12 cuboctahedra that share edges with six equivalent KH12 cuboctahedra, edges with six equivalent NaH12 cuboctahedra, and edges with six equivalent BH4 tetrahedra. There are six shorter (2.44 Å) and six longer (2.67 Å) Na–H bond lengths. B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share edges with three equivalent KH12 cuboctahedra and edges with three equivalent NaH12 cuboctahedra. There is one shorter (1.22 Å) and three longer (1.23 Å) B–H bond length. There are two inequivalent H+0.50+ sites. In the first H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to three equivalent Na1+ and one B3- atom. In the second H+0.50+ site, H+0.50+ is bonded in a distorted single-bond geometry to two equivalent K1+, one Na1+, and one B3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KNa(BH4)2 by Materials Project

NaK(BH4)2 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. K1+ is bonded to twelve H+0.50+ atoms to form KH12 cuboctahedra that share corners with six equivalent NaH6 octahedra, edges with six equivalent KH12 cuboctahedra, and edges with six equivalent BH4 tetrahedra. The corner-sharing octahedral tilt angles are 60°. There are six shorter (2.72 Å) and six longer (2.82 Å) K–H bond lengths. Na1+ is bonded to six equivalent H+0.50+ atoms to form NaH6 octahedra that share corners with six equivalent KH12 cuboctahedra and corners with six equivalent BH4 tetrahedra. All Na–H bond lengths are 2.42 Å. B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share corners with three equivalent NaH6 octahedra and edges with three equivalent KH12 cuboctahedra. The corner-sharing octahedral tilt angles are 66°. All B–H bond lengths are 1.23 Å. There are two inequivalent H+0.50+ sites. In the first H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to three equivalent K1+ and one B3- atom. In the second H+0.50+ site, H+0.50+ is bonded in a distorted single-bond geometry to one K1+, one Na1+, and one B3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KNa(BH4)2 by Materials Project

NaK(BH4)2 crystallizes in the trigonal R3 space group. The structure is three-dimensional. K1+ is bonded in a 12-coordinate geometry to twelve H+0.50+ atoms. There are a spread of K–H bond distances ranging from 2.71–2.83 Å. Na1+ is bonded in a 6-coordinate geometry to nine H+0.50+ atoms. There are a spread of Na–H bond distances ranging from 2.35–2.65 Å. There are two inequivalent B3- sites. In the first B3- site, B3- is bonded in a tetrahedral geometry to four H+0.50+ atoms. All B–H bond lengths are 1.23 Å. In the second B3- site, B3- is bonded in a tetrahedral geometry to four H+0.50+ atoms. All B–H bond lengths are 1.23 Å. There are four inequivalent H+0.50+ sites. In the first H+0.50+ site, H+0.50+ is bonded in a 1-coordinate geometry to one K1+, one Na1+, and one B3- atom. In the second H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to three equivalent Na1+ and one B3- atom. In the third H+0.50+ site, H+0.50+ is bonded in a distorted single-bond geometry to two equivalent K1+, one Na1+, and one B3- atom. In the fourth H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to three equivalent K1+ and one B3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KNa(BH4)2 by Materials Project

NaK(BH4)2 crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. K1+ is bonded in a 12-coordinate geometry to twelve H+0.50+ atoms. There are a spread of K–H bond distances ranging from 2.72–2.92 Å. Na1+ is bonded in a 9-coordinate geometry to nine H+0.50+ atoms. There are three shorter (2.45 Å) and six longer (2.48 Å) Na–H bond lengths. There are two inequivalent B3- sites. In the first B3- site, B3- is bonded in a tetrahedral geometry to four H+0.50+ atoms. All B–H bond lengths are 1.23 Å. In the second B3- site, B3- is bonded in a tetrahedral geometry to four H+0.50+ atoms. There is one shorter (1.22 Å) and three longer (1.23 Å) B–H bond length. There are four inequivalent H+0.50+ sites. In the first H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to three equivalent K1+ and one B3- atom. In the second H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to three equivalent K1+ and one B3- atom. In the third H+0.50+ site, H+0.50+ is bonded in a distorted single-bond geometry to two equivalent Na1+ and one B3- atom. In the fourth H+0.50+ site, H+0.50+ is bonded in a distorted single-bond geometry to two equivalent K1+, one Na1+, and one B3- atom.

36 MATERIALS SCIENCE↗