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DOE OSTI2020

Materials Data on K3TeP3O17 by Materials Project

K3Te(PO5)3O2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of four oxygen molecules and one K3Te(PO5)3 framework. In the K3Te(PO5)3 framework, there are three inequivalent K sites. In the first K site, K is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of K–O bond distances ranging from 2.73–2.97 Å. In the second K site, K is bonded to seven O atoms to form distorted KO7 pentagonal bipyramids that share corners with two equivalent KO7 pentagonal bipyramids, a cornercorner with one TeO4 tetrahedra, and corners with six PO4 tetrahedra. There are a spread of K–O bond distances ranging from 2.84–3.19 Å. In the third K site, K is bonded in a 5-coordinate geometry to five O atoms. There are a spread of K–O bond distances ranging from 2.64–3.16 Å. There are three inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share a cornercorner with one KO7 pentagonal bipyramid and corners with two PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.64 Å. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent KO7 pentagonal bipyramids and corners with two PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.63 Å. In the third P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three equivalent KO7 pentagonal bipyramids and corners with two PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.49–1.66 Å. Te is bonded to four O atoms to form TeO4 tetrahedra that share a cornercorner with one KO7 pentagonal bipyramid. There is two shorter (1.82 Å) and two longer (1.88 Å) Te–O bond length. There are fifteen inequivalent O sites. In the first O site, O is bonded in a distorted bent 120 degrees geometry to one K and one Te atom. In the second O site, O is bonded in a linear geometry to one K and one Te atom. In the third O site, O is bonded in a distorted trigonal non-coplanar geometry to two K and one Te atom. In the fourth O site, O is bonded in a water-like geometry to one K and one O atom. The O–O bond length is 1.23 Å. In the fifth O site, O is bonded in a linear geometry to one K and one Te atom. In the sixth O site, O is bonded in a distorted single-bond geometry to two K and one P atom. In the seventh O site, O is bonded in a distorted bent 120 degrees geometry to one K and one P atom. In the eighth O site, O is bonded in a distorted bent 150 degrees geometry to one K and one P atom. In the ninth O site, O is bonded in a distorted single-bond geometry to three K and one P atom. In the tenth O site, O is bonded in a distorted single-bond geometry to three K and one P atom. In the eleventh O site, O is bonded in a distorted single-bond geometry to two K and one P atom. In the twelfth O site, O is bonded in a bent 120 degrees geometry to two P atoms. In the thirteenth O site, O is bonded in a bent 120 degrees geometry to two P atoms. In the fourteenth O site, O is bonded in a 2-coordinate geometry to one K and two P atoms. In the fifteenth O site, O is bonded in a single-bond geometry to one O atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3Tl(Cl3O)2 by Materials Project

K21Tl7(OCl7)6(O2)4 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional and consists of four 1,2,3,4-tetraoxacyclobutane molecules and one K21Tl7(OCl7)6 framework. In the K21Tl7(OCl7)6 framework, there are four inequivalent K sites. In the first K site, K is bonded in an octahedral geometry to six O atoms. There are two shorter (2.55 Å) and four longer (2.90 Å) K–O bond lengths. In the second K site, K is bonded to six Cl atoms to form distorted KCl6 pentagonal pyramids that share corners with four TlCl6 octahedra, corners with two equivalent KCl6 pentagonal pyramids, and an edgeedge with one TlCl6 octahedra. The corner-sharing octahedra tilt angles range from 28–56°. There are a spread of K–Cl bond distances ranging from 3.06–3.37 Å. In the third K site, K is bonded in a 6-coordinate geometry to six Cl atoms. There are a spread of K–Cl bond distances ranging from 3.18–3.34 Å. In the fourth K site, K is bonded in a 8-coordinate geometry to one O and seven Cl atoms. The K–O bond length is 2.91 Å. There are a spread of K–Cl bond distances ranging from 3.18–3.59 Å. There are three inequivalent Tl sites. In the first Tl site, Tl is bonded to six Cl atoms to form TlCl6 octahedra that share edges with four equivalent KCl6 pentagonal pyramids. There are two shorter (2.40 Å) and four longer (2.79 Å) Tl–Cl bond lengths. In the second Tl site, Tl is bonded to six Cl atoms to form TlCl6 octahedra that share corners with four equivalent KCl6 pentagonal pyramids. There are two shorter (2.55 Å) and four longer (2.67 Å) Tl–Cl bond lengths. In the third Tl site, Tl is bonded to six Cl atoms to form TlCl6 octahedra that share corners with two equivalent KCl6 pentagonal pyramids. There are a spread of Tl–Cl bond distances ranging from 2.60–2.72 Å. There are two inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one K atom. In the second O site, O is bonded in a trigonal planar geometry to three K atoms. There are seven inequivalent Cl sites. In the first Cl site, Cl is bonded in a 4-coordinate geometry to three K and one Tl atom. In the second Cl site, Cl is bonded to four K and one Tl atom to form a mixture of distorted edge and corner-sharing ClK4Tl square pyramids. In the third Cl site, Cl is bonded in a distorted trigonal non-coplanar geometry to two equivalent K and one Tl atom. In the fourth Cl site, Cl is bonded in a distorted see-saw-like geometry to three K and one Tl atom. In the fifth Cl site, Cl is bonded in a single-bond geometry to one Tl atom. In the sixth Cl site, Cl is bonded to four K and one Tl atom to form a mixture of edge and corner-sharing ClK4Tl trigonal bipyramids. In the seventh Cl site, Cl is bonded to four K and one Tl atom to form a mixture of edge and corner-sharing ClK4Tl square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2V3P2O13F2 by Materials Project

K2V3P2O13F2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded in a 10-coordinate geometry to eight O and two F atoms. There are a spread of K–O bond distances ranging from 2.83–3.27 Å. There are one shorter (2.80 Å) and one longer (2.81 Å) K–F bond lengths. In the second K site, K is bonded in a 3-coordinate geometry to seven O and two F atoms. There are a spread of K–O bond distances ranging from 2.76–3.23 Å. There are one shorter (2.77 Å) and one longer (3.23 Å) K–F bond lengths. There are three inequivalent V sites. In the first V site, V is bonded to five O and one F atom to form distorted VO5F octahedra that share corners with four PO4 tetrahedra and a faceface with one VO5F octahedra. There are a spread of V–O bond distances ranging from 1.64–2.14 Å. The V–F bond length is 2.11 Å. In the second V site, V is bonded in a 6-coordinate geometry to four O and two equivalent F atoms. There are a spread of V–O bond distances ranging from 1.66–2.20 Å. There are one shorter (1.97 Å) and one longer (2.29 Å) V–F bond lengths. In the third V site, V is bonded to five O and one F atom to form distorted VO5F octahedra that share corners with four PO4 tetrahedra and a faceface with one VO5F octahedra. There are a spread of V–O bond distances ranging from 1.61–2.09 Å. The V–F bond length is 2.11 Å. There are two inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with four VO5F octahedra. The corner-sharing octahedra tilt angles range from 33–57°. There are a spread of P–O bond distances ranging from 1.51–1.59 Å. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with four VO5F octahedra. The corner-sharing octahedra tilt angles range from 31–55°. There are a spread of P–O bond distances ranging from 1.49–1.60 Å. There are thirteen inequivalent O sites. In the first O site, O is bonded in a 2-coordinate geometry to one K, one V, and one P atom. In the second O site, O is bonded in a distorted bent 150 degrees geometry to one K, one V, and one P atom. In the third O site, O is bonded in a 3-coordinate geometry to two V and one P atom. In the fourth O site, O is bonded in a bent 150 degrees geometry to one K, one V, and one P atom. In the fifth O site, O is bonded in a distorted bent 150 degrees geometry to one K, one V, and one P atom. In the sixth O site, O is bonded in a 1-coordinate geometry to one K, one V, and one P atom. In the seventh O site, O is bonded in a 3-coordinate geometry to two V and one P atom. In the eighth O site, O is bonded in a distorted bent 150 degrees geometry to one K, one V, and one P atom. In the ninth O site, O is bonded in a single-bond geometry to two K and one V atom. In the tenth O site, O is bonded in a distorted single-bond geometry to three K and one V atom. In the eleventh O site, O is bonded in a single-bond geometry to two K and one V atom. In the twelfth O site, O is bonded in a single-bond geometry to one K and one V atom. In the thirteenth O site, O is bonded in a single-bond geometry to one K atom. There are two inequivalent F sites. In the first F site, F is bonded in a 1-coordinate geometry to two K and two equivalent V atoms. In the second F site, F is bonded in a distorted trigonal pyramidal geometry to two K and two V atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

X-ray absorption spectroscopy and theoretical investigations of the effect of extended ligands in potassium organic matter interaction

Potassium (K) is an essential nutrient for plant growth, and despite its abundance in soil, most of the K is structurally bound in minerals, limiting its bioavailability and making this soil K reservoir largely inaccessible to plants. Microbial biochemical weathering has been shown to be a promising pathway to sustainably increase plant available K. However, the mechanisms underpinning microbial K uptake, transformation, storage, and sharing are poorly resolved. Here, to better understand the controls on microbial K transformations, we performed K K-edge x-ray absorption near-edge structure (XANES) spectroscopy on K-organic salts, including acetate, citrate, nitrate, oxalate, and tartrate, which are frequently observed as low molecular weight organic acids secreted by soil microbes, as well as humic acid, which acts as a proxy for higher molecular weight organic acids. The organic salts display feature-rich K XANES spectra, each demonstrating numerous unique features spanning ~13 eV range across the absorption edge. In contrast, the spectra for humic acid have one broad, wide feature across the same energy range. We used a combination of time-dependent density functional theory and the Bethe–Salpeter equation based approach within the OCEAN code to simulate the experimental spectra for K-nitrate (KNO 3 ) and K-citrate [K 3 (C 6 H 5 O 7 )·H 2 O] to identify the electronic transitions that give rise to some of the outlying and unique spectral features in the organic salts. KNO 3 has both the lowest and highest lying energy features, and K 3 (C 6 H 5 O 7 )·H 2 O is produced by several soil microbes and is effective at mineral weathering. Our results analyze the K-organic salt bonding in detail to elucidate why the spectral shapes differ and indicate that the K K-edge XANES spectra are associated with the entire ligand despite similar first-shell bonding environments around the K center. The improved understanding of K bonding environments with organic ligands and their use for interpretation of the K-XANES spectra provides an important toolkit to understand how K is transformed by microbial processes and made bioavailable for plant uptake.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on K5(AsPb)3 by Materials Project

K5(PbAs)3 is Magnesium tetraboride-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are four inequivalent K sites. In the first K site, K is bonded in a 6-coordinate geometry to three Pb and four As atoms. There are a spread of K–Pb bond distances ranging from 3.74–4.14 Å. There are a spread of K–As bond distances ranging from 3.33–3.68 Å. In the second K site, K is bonded in a 5-coordinate geometry to one Pb and four As atoms. The K–Pb bond length is 4.09 Å. There are a spread of K–As bond distances ranging from 3.74–3.77 Å. In the third K site, K is bonded in a 7-coordinate geometry to four Pb and three As atoms. There are a spread of K–Pb bond distances ranging from 3.71–3.86 Å. There are two shorter (3.23 Å) and one longer (3.49 Å) K–As bond lengths. In the fourth K site, K is bonded in a 8-coordinate geometry to four equivalent Pb and four As atoms. There are two shorter (3.62 Å) and two longer (3.87 Å) K–Pb bond lengths. There are two shorter (3.47 Å) and two longer (3.59 Å) K–As bond lengths. There are two inequivalent Pb sites. In the first Pb site, Pb is bonded in a 6-coordinate geometry to four K, one Pb, and two As atoms. The Pb–Pb bond length is 3.39 Å. There are one shorter (2.82 Å) and one longer (2.87 Å) Pb–As bond lengths. In the second Pb site, Pb is bonded in a 11-coordinate geometry to seven K, two equivalent Pb, and two equivalent As atoms. Both Pb–As bond lengths are 2.90 Å. There are two inequivalent As sites. In the first As site, As is bonded in a 9-coordinate geometry to seven K and two equivalent Pb atoms. In the second As site, As is bonded in a 8-coordinate geometry to six K and two Pb atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2B10H13O2 by Materials Project

K2B10H13O2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded in a 7-coordinate geometry to six H and one O atom. There are a spread of K–H bond distances ranging from 2.73–2.92 Å. The K–O bond length is 2.86 Å. In the second K site, K is bonded in a 11-coordinate geometry to nine H and two O atoms. There are a spread of K–H bond distances ranging from 2.74–3.06 Å. There are one shorter (3.04 Å) and one longer (3.25 Å) K–O bond lengths. There are ten inequivalent B sites. In the first B site, B is bonded in a distorted single-bond geometry to one H atom. The B–H bond length is 1.20 Å. In the second B site, B is bonded in a distorted single-bond geometry to one H atom. The B–H bond length is 1.21 Å. In the third B site, B is bonded in a distorted single-bond geometry to one H atom. The B–H bond length is 1.21 Å. In the fourth B site, B is bonded in a distorted single-bond geometry to one H atom. The B–H bond length is 1.21 Å. In the fifth B site, B is bonded in a distorted single-bond geometry to one H atom. The B–H bond length is 1.21 Å. In the sixth B site, B is bonded in a distorted single-bond geometry to one B and one H atom. The B–B bond length is 1.73 Å. The B–H bond length is 1.21 Å. In the seventh B site, B is bonded in a single-bond geometry to one B and one H atom. The B–B bond length is 1.73 Å. The B–H bond length is 1.22 Å. In the eighth B site, B is bonded in a distorted single-bond geometry to one B and one H atom. The B–B bond length is 1.72 Å. The B–H bond length is 1.20 Å. In the ninth B site, B is bonded in a distorted single-bond geometry to one B and one H atom. The B–B bond length is 1.72 Å. The B–H bond length is 1.21 Å. In the tenth B site, B is bonded in a 5-coordinate geometry to five B atoms. The B–B bond length is 1.69 Å. There are thirteen inequivalent H sites. In the first H site, H is bonded in a distorted single-bond geometry to two equivalent K and one B atom. In the second H site, H is bonded in a distorted water-like geometry to one K and one B atom. In the third H site, H is bonded in a distorted single-bond geometry to two equivalent K and one B atom. In the fourth H site, H is bonded in a single-bond geometry to one K and one B atom. In the fifth H site, H is bonded in a distorted single-bond geometry to two K and one B atom. In the sixth H site, H is bonded in a distorted single-bond geometry to two K and one B atom. In the seventh H site, H is bonded in a distorted single-bond geometry to one K and one B atom. In the eighth H site, H is bonded in a distorted single-bond geometry to two equivalent K and one B atom. In the ninth H site, H is bonded in a single-bond geometry to one K and one B atom. In the tenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the eleventh H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the twelfth H site, H is bonded in a single-bond geometry to one K and one O atom. The H–O bond length is 0.97 Å. In the thirteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. There are two inequivalent O sites. In the first O site, O is bonded in a water-like geometry to two K and two H atoms. In the second O site, O is bonded in a water-like geometry to one K and two H atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K4MoO8 by Materials Project

K4MoO8 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent K sites. In the first K site, K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.60–3.04 Å. In the second K site, K is bonded in a 4-coordinate geometry to five O atoms. There are a spread of K–O bond distances ranging from 2.56–3.31 Å. In the third K site, K is bonded in a 2-coordinate geometry to four O atoms. There are a spread of K–O bond distances ranging from 2.73–3.28 Å. In the fourth K site, K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.72–3.31 Å. Mo is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Mo–O bond distances ranging from 1.79–2.10 Å. There are eight inequivalent O sites. In the first O site, O is bonded to three K and one O atom to form distorted corner-sharing OK3O trigonal pyramids. The O–O bond length is 1.48 Å. In the second O site, O is bonded in a distorted single-bond geometry to two K and one Mo atom. In the third O site, O is bonded in a 1-coordinate geometry to three K and one Mo atom. In the fourth O site, O is bonded in a 3-coordinate geometry to one K and two O atoms. The O–O bond length is 1.47 Å. In the fifth O site, O is bonded in a 4-coordinate geometry to three K and one O atom. In the sixth O site, O is bonded in a 4-coordinate geometry to four K and one Mo atom. In the seventh O site, O is bonded in a 4-coordinate geometry to two K, one Mo, and one O atom. The O–O bond length is 1.54 Å. In the eighth O site, O is bonded to five K, one Mo, and one O atom to form distorted OK5MoO pentagonal bipyramids that share corners with two equivalent OK5MoO pentagonal bipyramids and corners with three equivalent OK3O trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3Zr2S(O2F3)3 by Materials Project

K3Zr2S(O2F3)3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent K sites. In the first K site, K is bonded in a 8-coordinate geometry to one O and seven F atoms. The K–O bond length is 3.13 Å. There are a spread of K–F bond distances ranging from 2.64–3.21 Å. In the second K site, K is bonded in a 8-coordinate geometry to three O and five F atoms. There are one shorter (2.85 Å) and two longer (2.88 Å) K–O bond lengths. There are a spread of K–F bond distances ranging from 2.73–3.02 Å. In the third K site, K is bonded in a 8-coordinate geometry to six O and two equivalent F atoms. There are a spread of K–O bond distances ranging from 2.91–3.01 Å. Both K–F bond lengths are 2.77 Å. Zr is bonded in a 8-coordinate geometry to one O and seven F atoms. The Zr–O bond length is 2.24 Å. There are a spread of Zr–F bond distances ranging from 2.02–2.24 Å. S is bonded in a tetrahedral geometry to four O atoms. There are a spread of S–O bond distances ranging from 1.48–1.51 Å. There are four inequivalent O sites. In the first O site, O is bonded in a distorted water-like geometry to one K and one Zr atom. In the second O site, O is bonded in a distorted single-bond geometry to two K and one S atom. In the third O site, O is bonded in a distorted single-bond geometry to two K and one S atom. In the fourth O site, O is bonded in a distorted single-bond geometry to two equivalent K and one S atom. There are six inequivalent F sites. In the first F site, F is bonded in a bent 120 degrees geometry to two equivalent Zr atoms. In the second F site, F is bonded in a 1-coordinate geometry to three K and one Zr atom. In the third F site, F is bonded in a tetrahedral geometry to two K and two equivalent Zr atoms. In the fourth F site, F is bonded in a linear geometry to two equivalent Zr atoms. In the fifth F site, F is bonded in a distorted trigonal non-coplanar geometry to two K and one Zr atom. In the sixth F site, F is bonded in a distorted trigonal non-coplanar geometry to one K and two equivalent Zr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3V2O12 by Materials Project

K3V2O12 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent K sites. In the first K site, K is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of K–O bond distances ranging from 2.82–3.26 Å. In the second K site, K is bonded in a 10-coordinate geometry to ten O atoms. There are a spread of K–O bond distances ranging from 2.82–3.16 Å. In the third K site, K is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of K–O bond distances ranging from 2.69–3.17 Å. There are two inequivalent V sites. In the first V site, V is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of V–O bond distances ranging from 1.66–2.54 Å. In the second V site, V is bonded in a 2-coordinate geometry to seven O atoms. There are a spread of V–O bond distances ranging from 1.65–2.64 Å. There are twelve inequivalent O sites. In the first O site, O is bonded in a 1-coordinate geometry to two K, two V, and one O atom. The O–O bond length is 1.44 Å. In the second O site, O is bonded in a linear geometry to two K atoms. In the third O site, O is bonded in a 5-coordinate geometry to two K, two V, and one O atom. The O–O bond length is 1.45 Å. In the fourth O site, O is bonded in a 1-coordinate geometry to three K, one V, and one O atom. In the fifth O site, O is bonded in a 1-coordinate geometry to two K, one V, and one O atom. The O–O bond length is 1.40 Å. In the sixth O site, O is bonded in a water-like geometry to two V atoms. In the seventh O site, O is bonded in a 1-coordinate geometry to two K, one V, and one O atom. In the eighth O site, O is bonded in a 1-coordinate geometry to three K, one V, and one O atom. The O–O bond length is 1.43 Å. In the ninth O site, O is bonded in a distorted single-bond geometry to three K and one V atom. In the tenth O site, O is bonded in a 1-coordinate geometry to three K, one V, and one O atom. In the eleventh O site, O is bonded in a distorted single-bond geometry to three K and one V atom. In the twelfth O site, O is bonded in a 1-coordinate geometry to three K, one V, and one O atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2CrMo6H19O32 by Materials Project

(K2Mo6CrH19O31)2O2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional and consists of two water molecules and one K2Mo6CrH19O31 framework. In the K2Mo6CrH19O31 framework, there are two inequivalent K sites. In the first K site, K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.78–3.06 Å. In the second K site, K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.78–3.24 Å. There are six inequivalent Mo sites. In the first Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.73–2.35 Å. In the second Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.73–2.36 Å. In the third Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.74–2.34 Å. In the fourth Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.73–2.33 Å. In the fifth Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.73–2.34 Å. In the sixth Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.73–2.35 Å. There are two inequivalent Cr sites. In the first Cr site, Cr is bonded in an octahedral geometry to six O atoms. There are four shorter (2.00 Å) and two longer (2.02 Å) Cr–O bond lengths. In the second Cr site, Cr is bonded in an octahedral geometry to six O atoms. All Cr–O bond lengths are 2.01 Å. There are nineteen inequivalent H sites. In the first H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the second H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the third H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the fourth H site, H is bonded in a single-bond geometry to two O atoms. There is one shorter (1.00 Å) and one longer (1.74 Å) H–O bond length. In the fifth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the sixth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the seventh H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.00 Å) and one longer (1.68 Å) H–O bond length. In the eighth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the ninth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the tenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the eleventh H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.62 Å) H–O bond length. In the twelfth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the thirteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the fourteenth H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.59 Å) H–O bond length. In the fifteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the sixteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the seventeenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the eighteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.97 Å. In the nineteenth H site, H is bonded in a linear geometry to two O atoms. There is one shorter (1.12 Å) and one longer (1.29 Å) H–O bond length. There are thirty-one inequivalent O sites. In the first O site, O is bonded in a water-like geometry to one K and two H atoms. In the second O site, O is bonded in a trigonal planar geometry to two Mo and one H atom. In the third O site, O is bonded in a distorted single-bond geometry to one K and one Mo atom. In the fourth O site, O is bonded in a distorted trigonal planar geometry to two Mo and one H atom. In the fifth O site, O is bonded in a single-bond geometry to one H atom. In the sixth O site, O is bonded in a water-like geometry to one K and two H atoms. In the seventh O site, O is bonded in a distorted single-bond geometry to two Mo, one Cr, and one H atom. In the eighth O site, O is bonded in a distorted bent 150 degrees geometry to one Mo and one H atom. In the ninth O site, O is bonded in a distorted single-bond geometry to two Mo, one Cr, and one H atom. In the tenth O site, O is bonded in a single-bond geometry to one Mo atom. In the eleventh O site, O is bonded in a distorted single-bond geometry to two Mo, one Cr, and one H atom. In the twelfth O site, O is bonded in a water-like geometry to one K and two H atoms. In the thirteenth O site, O is bonded in a distorted single-bond geometry to two Mo, one Cr, and one H atom. In the fourteenth O site, O is bonded in a single-bond geometry to one Mo atom. In the fifteenth O site, O is bonded in a distorted single-bond geometry to one K and one Mo atom. In the sixteenth O site, O is bonded in a distorted single-bond geometry to one K and one Mo atom. In the seventeenth O site, O is bonded in a distorted trigonal planar geometry to two Mo and one H atom. In the eighteenth O site, O is bonded in a water-like geometry to two equivalent K and two H atoms. In the nineteenth O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the twentieth O site, O is bonded in a water-like geometry to one K and two H atoms. In the twenty-first O site, O is bonded in a distorted bent 150 degrees geometry to one K and one Mo atom. In the twenty-second O site, O is bonded in a distorted single-bond geometry to two Mo, one Cr, and one H atom. In the twenty-third O site, O is bonded in a single-bond geometry to one Mo atom. In the twenty-fourth O site, O is bonded in a distorted single-bond geometry to two Mo, one Cr, and one H atom. In the twenty-fifth O site, O is bonded in a trigonal planar geometry to one K and two Mo atoms. In the twenty-sixth O site, O is bonded in a distorted single-bond geometry to two K and one Mo atom. In the twenty-seventh O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the twenty-eighth O site, O is bonded in a single-bond geometry to one K and one Mo atom. In the twenty-ninth O site, O is bonded in a 2-coordinate geometry to one K and three H atoms. In the thirtieth O site, O is bonded in a single-bond geometry to one Mo atom. In the thirty-first O site, O is bonded in a distorted single-bond geometry to one K and one Mo atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K6Bi6O19 by Materials Project

K6Bi6O19 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are three inequivalent K sites. In the first K site, K is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of K–O bond distances ranging from 2.79–3.11 Å. In the second K site, K is bonded in a 10-coordinate geometry to ten O atoms. There are a spread of K–O bond distances ranging from 2.69–3.29 Å. In the third K site, K is bonded in a 4-coordinate geometry to seven O atoms. There are a spread of K–O bond distances ranging from 2.67–3.14 Å. There are four inequivalent Bi sites. In the first Bi site, Bi is bonded to six O atoms to form a mixture of corner and edge-sharing BiO6 octahedra. The corner-sharing octahedra tilt angles range from 53–54°. There are a spread of Bi–O bond distances ranging from 2.15–2.17 Å. In the second Bi site, Bi is bonded to six O atoms to form a mixture of corner and edge-sharing BiO6 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Bi–O bond distances ranging from 2.12–2.18 Å. In the third Bi site, Bi is bonded to six O atoms to form a mixture of corner and edge-sharing BiO6 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Bi–O bond distances ranging from 2.13–2.18 Å. In the fourth Bi site, Bi is bonded to six O atoms to form a mixture of corner and edge-sharing BiO6 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Bi–O bond distances ranging from 2.13–2.18 Å. There are eleven inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to two equivalent K and two Bi atoms. In the second O site, O is bonded in a 3-coordinate geometry to two K and two Bi atoms. In the third O site, O is bonded to two K and two Bi atoms to form distorted corner-sharing OK2Bi2 trigonal pyramids. In the fourth O site, O is bonded to two K and two Bi atoms to form distorted corner-sharing OK2Bi2 tetrahedra. In the fifth O site, O is bonded in a 4-coordinate geometry to two K and two Bi atoms. In the sixth O site, O is bonded in a 6-coordinate geometry to six K atoms. In the seventh O site, O is bonded in a distorted water-like geometry to four K and two equivalent Bi atoms. In the eighth O site, O is bonded in a 4-coordinate geometry to two equivalent K and two equivalent Bi atoms. In the ninth O site, O is bonded in a 2-coordinate geometry to three K and two equivalent Bi atoms. In the tenth O site, O is bonded in a distorted water-like geometry to three K and two Bi atoms. In the eleventh O site, O is bonded in a 2-coordinate geometry to two K and two Bi atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3ZrC3O13 by Materials Project

K3ZrC3O13 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent K sites. In the first K site, K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.71–2.89 Å. In the second K site, K is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of K–O bond distances ranging from 2.67–2.98 Å. In the third K site, K is bonded in a 5-coordinate geometry to five O atoms. There are a spread of K–O bond distances ranging from 2.69–3.22 Å. Zr is bonded to eight O atoms to form edge-sharing ZrO8 hexagonal bipyramids. There are a spread of Zr–O bond distances ranging from 2.16–2.28 Å. There are three inequivalent C sites. In the first C site, C is bonded in a trigonal planar geometry to three O atoms. There is one shorter (1.25 Å) and two longer (1.33 Å) C–O bond length. In the second C site, C is bonded in a trigonal planar geometry to three O atoms. There are a spread of C–O bond distances ranging from 1.28–1.32 Å. In the third C site, C is bonded in a trigonal planar geometry to three O atoms. There are a spread of C–O bond distances ranging from 1.25–1.34 Å. There are thirteen inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to two K and one C atom. In the second O site, O is bonded in an L-shaped geometry to one Zr and one C atom. In the third O site, O is bonded in a 1-coordinate geometry to one K, one Zr, and one C atom. In the fourth O site, O is bonded in a distorted L-shaped geometry to one K and one O atom. The O–O bond length is 1.25 Å. In the fifth O site, O is bonded in a 3-coordinate geometry to one K, one Zr, and one C atom. In the sixth O site, O is bonded in an L-shaped geometry to one K and one O atom. In the seventh O site, O is bonded in a 1-coordinate geometry to one K, one Zr, and one C atom. In the eighth O site, O is bonded in a 1-coordinate geometry to two K, one Zr, and one C atom. In the ninth O site, O is bonded in a water-like geometry to two K atoms. In the tenth O site, O is bonded in a 1-coordinate geometry to two K, one Zr, and one C atom. In the eleventh O site, O is bonded in a distorted single-bond geometry to three K and one C atom. In the twelfth O site, O is bonded in a distorted single-bond geometry to two K and one C atom. In the thirteenth O site, O is bonded in a 2-coordinate geometry to two equivalent Zr and one O atom. The O–O bond length is 1.53 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3TaO2F7 by Materials Project

K3TaO2F7 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are three inequivalent K sites. In the first K site, K is bonded in a 6-coordinate geometry to six F atoms. There are a spread of K–F bond distances ranging from 2.60–3.13 Å. In the second K site, K is bonded in a 8-coordinate geometry to one O and seven F atoms. The K–O bond length is 2.97 Å. There are a spread of K–F bond distances ranging from 2.49–3.13 Å. In the third K site, K is bonded in a 6-coordinate geometry to one O and five F atoms. The K–O bond length is 3.02 Å. There are a spread of K–F bond distances ranging from 2.48–2.92 Å. Ta is bonded in a distorted pentagonal bipyramidal geometry to two O and five F atoms. Both Ta–O bond lengths are 2.12 Å. There are a spread of Ta–F bond distances ranging from 1.92–1.96 Å. There are two inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to one K, one Ta, and one O atom. The O–O bond length is 1.37 Å. In the second O site, O is bonded in a 3-coordinate geometry to one K, one Ta, and one O atom. There are seven inequivalent F sites. In the first F site, F is bonded in a distorted single-bond geometry to two K and one Ta atom. In the second F site, F is bonded in a distorted single-bond geometry to two K and one Ta atom. In the third F site, F is bonded in a distorted single-bond geometry to two K and one Ta atom. In the fourth F site, F is bonded in a distorted rectangular see-saw-like geometry to four K atoms. In the fifth F site, F is bonded to four K atoms to form distorted edge-sharing FK4 tetrahedra. In the sixth F site, F is bonded in a distorted trigonal non-coplanar geometry to two K and one Ta atom. In the seventh F site, F is bonded in a distorted single-bond geometry to two K and one Ta atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K5Hf3OF17 by Materials Project

K5Hf3OF17 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent K sites. In the first K site, K is bonded in a 9-coordinate geometry to one O and eight F atoms. The K–O bond length is 3.13 Å. There are a spread of K–F bond distances ranging from 2.61–3.20 Å. In the second K site, K is bonded in a 8-coordinate geometry to eight F atoms. There are a spread of K–F bond distances ranging from 2.62–3.01 Å. In the third K site, K is bonded in a 7-coordinate geometry to seven F atoms. There are a spread of K–F bond distances ranging from 2.71–2.83 Å. There are two inequivalent Hf sites. In the first Hf site, Hf is bonded to seven F atoms to form a mixture of edge and corner-sharing HfF7 pentagonal bipyramids. There are a spread of Hf–F bond distances ranging from 2.00–2.18 Å. In the second Hf site, Hf is bonded to seven F atoms to form distorted corner-sharing HfF7 pentagonal bipyramids. There are a spread of Hf–F bond distances ranging from 2.01–2.18 Å. O is bonded in a 2-coordinate geometry to two equivalent K atoms. There are ten inequivalent F sites. In the first F site, F is bonded in a 1-coordinate geometry to three K and one Hf atom. In the second F site, F is bonded in a distorted bent 120 degrees geometry to one K and two equivalent Hf atoms. In the third F site, F is bonded in a 1-coordinate geometry to three K and one Hf atom. In the fourth F site, F is bonded in a 1-coordinate geometry to four equivalent K and one Hf atom. In the fifth F site, F is bonded to three K and one Hf atom to form distorted corner-sharing FK3Hf tetrahedra. In the sixth F site, F is bonded in a distorted trigonal non-coplanar geometry to two K and one Hf atom. In the seventh F site, F is bonded in a linear geometry to two Hf atoms. In the eighth F site, F is bonded in a 4-coordinate geometry to three K and one Hf atom. In the ninth F site, F is bonded in a distorted trigonal non-coplanar geometry to two equivalent K and one Hf atom. In the tenth F site, F is bonded in a 1-coordinate geometry to three K and one Hf atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3As2O11 by Materials Project

K3As2O11 crystallizes in the orthorhombic Pca2_1 space group. The structure is three-dimensional. there are three inequivalent K sites. In the first K site, K is bonded in a 2-coordinate geometry to nine O atoms. There are a spread of K–O bond distances ranging from 2.70–3.36 Å. In the second K site, K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.55–3.24 Å. In the third K site, K is bonded in a 2-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.58–3.30 Å. There are two inequivalent As sites. In the first As site, As is bonded to four O atoms to form edge-sharing AsO4 tetrahedra. There are a spread of As–O bond distances ranging from 1.65–1.85 Å. In the second As site, As is bonded to four O atoms to form distorted edge-sharing AsO4 tetrahedra. There are a spread of As–O bond distances ranging from 1.66–1.87 Å. There are eleven inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one K and one As atom. In the second O site, O is bonded in a 2-coordinate geometry to two K and one As atom. In the third O site, O is bonded in a 3-coordinate geometry to two K and one O atom. The O–O bond length is 1.24 Å. In the fourth O site, O is bonded in a distorted L-shaped geometry to two K and two As atoms. In the fifth O site, O is bonded in a T-shaped geometry to three K atoms. In the sixth O site, O is bonded in a distorted L-shaped geometry to two K and one O atom. In the seventh O site, O is bonded in a 3-coordinate geometry to two K and two As atoms. In the eighth O site, O is bonded in a 4-coordinate geometry to three K and one O atom. The O–O bond length is 1.25 Å. In the ninth O site, O is bonded in a single-bond geometry to one K and one As atom. In the tenth O site, O is bonded in a 4-coordinate geometry to three K and one O atom. In the eleventh O site, O is bonded in a distorted T-shaped geometry to two K and one As atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K4ZrC5O15F2 by Materials Project

K4ZrC5O15F2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent K sites. In the first K site, K is bonded in a 7-coordinate geometry to five O and two F atoms. There are a spread of K–O bond distances ranging from 2.74–3.14 Å. There are one shorter (2.53 Å) and one longer (2.77 Å) K–F bond lengths. In the second K site, K is bonded in a 6-coordinate geometry to five O and one F atom. There are a spread of K–O bond distances ranging from 2.69–2.88 Å. The K–F bond length is 2.67 Å. In the third K site, K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.64–3.03 Å. Zr is bonded in a 8-coordinate geometry to six O and two F atoms. There are a spread of Zr–O bond distances ranging from 2.22–2.35 Å. There are one shorter (2.03 Å) and one longer (2.10 Å) Zr–F bond lengths. There are three inequivalent C sites. In the first C site, C is bonded in a distorted bent 120 degrees geometry to two O atoms. There is one shorter (1.25 Å) and one longer (1.29 Å) C–O bond length. In the second C site, C is bonded in a distorted bent 120 degrees geometry to two O atoms. There is one shorter (1.25 Å) and one longer (1.28 Å) C–O bond length. In the third C site, C is bonded in a trigonal planar geometry to three O atoms. There is one shorter (1.26 Å) and two longer (1.32 Å) C–O bond length. There are eight inequivalent O sites. In the first O site, O is bonded in a water-like geometry to one K and one O atom. The O–O bond length is 1.24 Å. In the second O site, O is bonded in a distorted trigonal planar geometry to one K, one Zr, and one C atom. In the third O site, O is bonded in a distorted single-bond geometry to two equivalent K, one Zr, and one C atom. In the fourth O site, O is bonded in a distorted rectangular see-saw-like geometry to three K and one C atom. In the fifth O site, O is bonded in an L-shaped geometry to one Zr and one C atom. In the sixth O site, O is bonded in a 1-coordinate geometry to two K and one C atom. In the seventh O site, O is bonded in a 1-coordinate geometry to two K and one C atom. In the eighth O site, O is bonded in a distorted L-shaped geometry to one K and one O atom. The O–O bond length is 1.24 Å. There are two inequivalent F sites. In the first F site, F is bonded in a distorted trigonal planar geometry to two equivalent K and one Zr atom. In the second F site, F is bonded in a rectangular see-saw-like geometry to three K and one Zr atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K5Hg7 by Materials Project

K5Hg7 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are five inequivalent K sites. In the first K site, K is bonded in a 8-coordinate geometry to eight Hg atoms. There are a spread of K–Hg bond distances ranging from 3.56–3.85 Å. In the second K site, K is bonded in a 8-coordinate geometry to eight Hg atoms. There are a spread of K–Hg bond distances ranging from 3.70–3.78 Å. In the third K site, K is bonded in a 2-coordinate geometry to eight Hg atoms. There are a spread of K–Hg bond distances ranging from 3.56–3.93 Å. In the fourth K site, K is bonded in a 8-coordinate geometry to twelve Hg atoms. There are a spread of K–Hg bond distances ranging from 3.70–4.06 Å. In the fifth K site, K is bonded in a 10-coordinate geometry to ten Hg atoms. There are a spread of K–Hg bond distances ranging from 3.58–3.81 Å. There are four inequivalent Hg sites. In the first Hg site, Hg is bonded in a 10-coordinate geometry to seven K and three Hg atoms. There are a spread of Hg–Hg bond distances ranging from 3.10–3.19 Å. In the second Hg site, Hg is bonded in a 10-coordinate geometry to eight K and two equivalent Hg atoms. Both Hg–Hg bond lengths are 3.33 Å. In the third Hg site, Hg is bonded in a 1-coordinate geometry to six K and three Hg atoms. There are one shorter (3.12 Å) and one longer (3.23 Å) Hg–Hg bond lengths. In the fourth Hg site, Hg is bonded in a 10-coordinate geometry to six K and four Hg atoms. The Hg–Hg bond length is 3.09 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3AlAs2 by Materials Project

K3AlAs2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are twelve inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 1-coordinate geometry to two K1+ and six As3- atoms. There are one shorter (3.24 Å) and one longer (3.46 Å) K–K bond lengths. There are a spread of K–As bond distances ranging from 3.29–3.63 Å. In the second K1+ site, K1+ is bonded in a 5-coordinate geometry to six As3- atoms. There are a spread of K–As bond distances ranging from 3.40–3.76 Å. In the third K1+ site, K1+ is bonded in a distorted see-saw-like geometry to four As3- atoms. There are a spread of K–As bond distances ranging from 3.26–3.49 Å. In the fourth K1+ site, K1+ is bonded in a 4-coordinate geometry to one K1+ and four As3- atoms. There are a spread of K–As bond distances ranging from 3.19–3.45 Å. In the fifth K1+ site, K1+ is bonded in a 4-coordinate geometry to one K1+ and four As3- atoms. The K–K bond length is 3.56 Å. There are a spread of K–As bond distances ranging from 3.33–3.52 Å. In the sixth K1+ site, K1+ is bonded in a distorted see-saw-like geometry to four As3- atoms. There are a spread of K–As bond distances ranging from 3.33–3.72 Å. In the seventh K1+ site, K1+ is bonded to one K1+ and four As3- atoms to form distorted KKAs4 trigonal pyramids that share corners with two AlAs4 tetrahedra and an edgeedge with one AlAs4 tetrahedra. There are a spread of K–As bond distances ranging from 3.26–3.47 Å. In the eighth K1+ site, K1+ is bonded in a 2-coordinate geometry to three As3- atoms. There are a spread of K–As bond distances ranging from 3.43–3.82 Å. In the ninth K1+ site, K1+ is bonded in a 4-coordinate geometry to four As3- atoms. There are a spread of K–As bond distances ranging from 3.33–3.66 Å. In the tenth K1+ site, K1+ is bonded in a 8-coordinate geometry to two K1+ and five As3- atoms. The K–K bond length is 3.38 Å. There are a spread of K–As bond distances ranging from 3.54–3.88 Å. In the eleventh K1+ site, K1+ is bonded in a 6-coordinate geometry to two K1+ and four As3- atoms. There are one shorter (3.33 Å) and one longer (3.42 Å) K–K bond lengths. There are a spread of K–As bond distances ranging from 3.34–3.66 Å. In the twelfth K1+ site, K1+ is bonded in a 3-coordinate geometry to one K1+ and four As3- atoms. There are a spread of K–As bond distances ranging from 3.35–3.78 Å. There are four inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four As3- atoms to form AlAs4 tetrahedra that share a cornercorner with one KKAs4 trigonal pyramid and edges with two AlAs4 tetrahedra. There are three shorter (2.54 Å) and one longer (2.56 Å) Al–As bond lengths. In the second Al3+ site, Al3+ is bonded to four As3- atoms to form AlAs4 tetrahedra that share a cornercorner with one KKAs4 trigonal pyramid, edges with two AlAs4 tetrahedra, and an edgeedge with one KKAs4 trigonal pyramid. There are a spread of Al–As bond distances ranging from 2.55–2.61 Å. In the third Al3+ site, Al3+ is bonded in a trigonal planar geometry to three As3- atoms. There are a spread of Al–As bond distances ranging from 2.37–2.49 Å. In the fourth Al3+ site, Al3+ is bonded in a trigonal planar geometry to three As3- atoms. There are a spread of Al–As bond distances ranging from 2.36–2.48 Å. There are eight inequivalent As3- sites. In the first As3- site, As3- is bonded in a 9-coordinate geometry to seven K1+ and two Al3+ atoms. In the second As3- site, As3- is bonded in a 2-coordinate geometry to seven K1+ and two equivalent Al3+ atoms. In the third As3- site, As3- is bonded in a 9-coordinate geometry to seven K1+ and two Al3+ atoms. In the fourth As3- site, As3- is bonded in a 2-coordinate geometry to seven K1+ and two equivalent Al3+ atoms. In the fifth As3- site, As3- is bonded in a 1-coordinate geometry to six K1+ and one Al3+ atom. In the sixth As3- site, As3- is bonded in a 1-coordinate geometry to seven K1+ and one Al3+ atom. In the seventh As3- site, As3- is bonded in a 4-coordinate geometry to five K1+ and two Al3+ atoms. In the eighth As3- site, As3- is bonded in a 8-coordinate geometry to six K1+ and two Al3+ atoms.

36 MATERIALS SCIENCE↗