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DOE OSTI2020

Materials Data on KDy3F10 by Materials Project

KDy3F10 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. K1+ is bonded to sixteen F1- atoms to form distorted edge-sharing KF16 tetrahedra. There are four shorter (2.78 Å) and twelve longer (3.23 Å) K–F bond lengths. Dy3+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are four shorter (2.22 Å) and four longer (2.38 Å) Dy–F bond lengths. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a bent 150 degrees geometry to two equivalent K1+ and two equivalent Dy3+ atoms. In the second F1- site, F1- is bonded to one K1+ and three equivalent Dy3+ atoms to form a mixture of edge and corner-sharing FKDy3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2Ag4S3 by Materials Project

K2Ag4S3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six S2- atoms to form a mixture of distorted corner, edge, and face-sharing KS6 octahedra. The corner-sharing octahedra tilt angles range from 40–64°. There are a spread of K–S bond distances ranging from 3.35–3.39 Å. In the second K1+ site, K1+ is bonded to six S2- atoms to form a mixture of distorted corner, edge, and face-sharing KS6 octahedra. The corner-sharing octahedra tilt angles range from 40–64°. There are a spread of K–S bond distances ranging from 3.17–3.41 Å. There are four inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a distorted trigonal planar geometry to three S2- atoms. There are two shorter (2.57 Å) and one longer (2.63 Å) Ag–S bond lengths. In the second Ag1+ site, Ag1+ is bonded in a distorted trigonal planar geometry to three S2- atoms. There are two shorter (2.49 Å) and one longer (2.71 Å) Ag–S bond lengths. In the third Ag1+ site, Ag1+ is bonded in a distorted trigonal planar geometry to three S2- atoms. There are one shorter (2.55 Å) and two longer (2.73 Å) Ag–S bond lengths. In the fourth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are one shorter (2.52 Å) and two longer (2.75 Å) Ag–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 9-coordinate geometry to three K1+ and six Ag1+ atoms. In the second S2- site, S2- is bonded in a 7-coordinate geometry to four K1+ and three Ag1+ atoms. In the third S2- site, S2- is bonded in a 8-coordinate geometry to five K1+ and three Ag1+ atoms.

36 MATERIALS SCIENCE↗
NASA NTRS2012

The Gray Needle: Large Grains in the HD 15115 Debris Disk from LBT*/PISCES/K s and LBTIi+/LMIRcam/L(prime) Adaptive Optics Imaging

We present diffraction-limited K s band and L(prime) adaptive optics images of the edge-on debris disk around the nearby F2 star HD 15115, obtained with a single 8.4 m primary mirror at the Large Binocular Telescope. At the Ks band, the disk is detected at signal-to-noise per resolution element (SNRE) approx. 3-8 from approx. 1 to 2".5 (45-113 AU) on the western side and from approx. 1". 2 to 2".1 (63-90 AU) on the east. At L the disk is detected at SNRE approx. 2.5 from approx. 1 to 1".45 (45-90 AU) on both sides, implying more symmetric disk structure at 3.8 micrometers. At both wavelengths the disk has a bow-like shape and is offset from the star to the north by a few AU. A surface brightness asymmetry exists between the two sides of the disk at the Ks band, but not at L(prime). The surface brightness at the K s band declines inside 1"(approx. 45 AU), which may be indicative of a gap in the disk near 1".The K s − L(prime) disk color, after removal of the stellar color, is mostly gray for both sides of the disk. This suggests that scattered light is coming from large dust grains, with 3-10 micrometers sized grains on the east side and 1-10 micrometers dust grains on the west. This may suggest that the west side is composed of smaller dust grains than the east side, which would support the interpretation that the disk is being dynamically affected by interactions with the local interstellar medium.

signal-to-noise↗
DOE OSTI2020

Materials Data on KNaH2 by Materials Project

KNaH2 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. K1+ is bonded to six H1- atoms to form KH6 octahedra that share corners with six equivalent KH6 octahedra, edges with four equivalent KH6 octahedra, and edges with eight equivalent NaH6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.67 Å) and four longer (2.68 Å) K–H bond lengths. Na1+ is bonded to six H1- atoms to form NaH6 octahedra that share corners with six equivalent NaH6 octahedra, edges with four equivalent NaH6 octahedra, and edges with eight equivalent KH6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.67 Å) and four longer (2.68 Å) Na–H bond lengths. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded to four equivalent K1+ and two equivalent Na1+ atoms to form a mixture of edge and corner-sharing HK4Na2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second H1- site, H1- is bonded to two equivalent K1+ and four equivalent Na1+ atoms to form HK2Na4 octahedra that share corners with six equivalent HK2Na4 octahedra and edges with twelve HK4Na2 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KFeS2 by Materials Project

KFeS2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K1+ is bonded to eight equivalent S2- atoms to form distorted KS8 hexagonal bipyramids that share corners with four equivalent KS8 hexagonal bipyramids, corners with six equivalent FeS4 tetrahedra, edges with six equivalent KS8 hexagonal bipyramids, edges with five equivalent FeS4 tetrahedra, and faces with two equivalent KS8 hexagonal bipyramids. There are a spread of K–S bond distances ranging from 3.37–3.45 Å. Fe3+ is bonded to four equivalent S2- atoms to form FeS4 tetrahedra that share corners with six equivalent KS8 hexagonal bipyramids, edges with five equivalent KS8 hexagonal bipyramids, and edges with two equivalent FeS4 tetrahedra. There are two shorter (2.18 Å) and two longer (2.19 Å) Fe–S bond lengths. S2- is bonded in a 6-coordinate geometry to four equivalent K1+ and two equivalent Fe3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KFeSe2 by Materials Project

KFeSe2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K1+ is bonded to eight equivalent Se2- atoms to form distorted KSe8 hexagonal bipyramids that share corners with four equivalent KSe8 hexagonal bipyramids, corners with six equivalent FeSe4 tetrahedra, edges with six equivalent KSe8 hexagonal bipyramids, edges with five equivalent FeSe4 tetrahedra, and faces with two equivalent KSe8 hexagonal bipyramids. There are a spread of K–Se bond distances ranging from 3.49–3.59 Å. Fe3+ is bonded to four equivalent Se2- atoms to form FeSe4 tetrahedra that share corners with six equivalent KSe8 hexagonal bipyramids, edges with five equivalent KSe8 hexagonal bipyramids, and edges with two equivalent FeSe4 tetrahedra. There are two shorter (2.33 Å) and two longer (2.35 Å) Fe–Se bond lengths. Se2- is bonded in a 6-coordinate geometry to four equivalent K1+ and two equivalent Fe3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KC2N3 by Materials Project

KC2N3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. K1+ is bonded to seven N3- atoms to form a mixture of distorted edge and face-sharing KN7 pentagonal bipyramids. There are a spread of K–N bond distances ranging from 2.84–3.23 Å. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a linear geometry to two N3- atoms. There is one shorter (1.19 Å) and one longer (1.30 Å) C–N bond length. In the second C4+ site, C4+ is bonded in a linear geometry to two N3- atoms. There is one shorter (1.18 Å) and one longer (1.30 Å) C–N bond length. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded to three equivalent K1+ and one C4+ atom to form a mixture of distorted edge and corner-sharing NK3C tetrahedra. In the second N3- site, N3- is bonded in a 1-coordinate geometry to two equivalent K1+ and one C4+ atom. In the third N3- site, N3- is bonded in a distorted bent 120 degrees geometry to two equivalent K1+ and two C4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3NaTh2O6 by Materials Project

K3NaTh2O6 is High Pressure (4-7GPa) Tellurium-derived structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six O2- atoms to form distorted KO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with four ThO6 octahedra, edges with two equivalent NaO6 octahedra, edges with four ThO6 octahedra, and edges with six equivalent KO6 octahedra. The corner-sharing octahedra tilt angles range from 13–18°. There are two shorter (2.70 Å) and four longer (2.95 Å) K–O bond lengths. In the second K1+ site, K1+ is bonded to six O2- atoms to form distorted KO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with four ThO6 octahedra, edges with two equivalent NaO6 octahedra, edges with four ThO6 octahedra, and edges with six KO6 octahedra. The corner-sharing octahedra tilt angles range from 14–17°. There are a spread of K–O bond distances ranging from 2.76–2.97 Å. Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six KO6 octahedra, edges with six KO6 octahedra, and edges with six ThO6 octahedra. The corner-sharing octahedra tilt angles range from 17–18°. There are four shorter (2.64 Å) and two longer (2.65 Å) Na–O bond lengths. There are two inequivalent Th4+ sites. In the first Th4+ site, Th4+ is bonded to six O2- atoms to form ThO6 octahedra that share corners with six KO6 octahedra, edges with three equivalent NaO6 octahedra, edges with three equivalent ThO6 octahedra, and edges with six KO6 octahedra. The corner-sharing octahedra tilt angles range from 13–14°. There are four shorter (2.35 Å) and two longer (2.36 Å) Th–O bond lengths. In the second Th4+ site, Th4+ is bonded to six O2- atoms to form ThO6 octahedra that share corners with six KO6 octahedra, edges with three equivalent NaO6 octahedra, edges with three equivalent ThO6 octahedra, and edges with six KO6 octahedra. The corner-sharing octahedra tilt angles range from 13–14°. All Th–O bond lengths are 2.35 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three K1+, one Na1+, and two Th4+ atoms to form a mixture of distorted edge and corner-sharing OK3NaTh2 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. In the second O2- site, O2- is bonded to three K1+, one Na1+, and two Th4+ atoms to form a mixture of distorted edge and corner-sharing OK3NaTh2 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. In the third O2- site, O2- is bonded to three K1+, one Na1+, and two Th4+ atoms to form a mixture of distorted edge and corner-sharing OK3NaTh2 octahedra. The corner-sharing octahedra tilt angles range from 0–10°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KNiTeO6 by Materials Project

KNiTeO6 crystallizes in the trigonal P312 space group. The structure is three-dimensional. K is bonded in a 6-coordinate geometry to six equivalent O atoms. All K–O bond lengths are 2.76 Å. Ni is bonded to six equivalent O atoms to form NiO6 octahedra that share edges with three equivalent TeO6 octahedra. All Ni–O bond lengths are 1.88 Å. Te is bonded to six equivalent O atoms to form TeO6 octahedra that share edges with three equivalent NiO6 octahedra. All Te–O bond lengths are 1.96 Å. O is bonded in a 3-coordinate geometry to one K, one Ni, and one Te atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Advanced EXAFS analysis techniques applied to the L -edges of the lanthanide oxides

The unique properties of the lanthanide (Ln) elements make them critical components of modern technologies, such as lasers, anti-corrosive films and catalysts. Thus, there is significant interest in establishing structure–property relationships for Ln-containing materials to advance these technologies. Extended X-ray absorption fine structure (EXAFS) is an excellent technique for this task considering its ability to determine the average local structure around the Ln atoms for both crystalline and amorphous materials. However, the limited availability of EXAFS reference spectra of the Ln oxides and challenges in the EXAFS analysis have hindered the application of this technique to these elements. The challenges include the limited k-range available for the analysis due to the superposition of L-edges on the EXAFS, multielectron excitations (MEEs) creating erroneous peaks in the EXAFS and the presence of inequivalent absorption sites. Herein, we removed MEEs to model the local atomic environment more accurately for light Ln oxides. Further, we investigated the use of cubic and non-cubic lattice expansion to minimize the fitting parameters needed and connect the fitting parameters to physically meaningful crystal parameters. The cubic expansion reduced the number of fitting parameters but resulted in a statistically worse fit. The non-cubic expansion resulted in a similar quality fit and showed non-isotropic expansion in the crystal lattice of Nd 2 O 3 . In total, the EXAFS spectra and the fits for the entire set of Ln oxides (excluding promethium) are included. The knowledge developed here can assist in the structural determination of a wide variety of Ln compounds and can further studies on their structure–property relationships.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Oxophilicity Drives Oxygen Transfer at a Palladium–Silver Interface for Increased CO Oxidation Activity

A single-layer AgO x phase grown on Ag(111) efficiently transfers oxygen to Pd domains at room temperature, rendering the Pd-decorated surface highly reactive toward CO oxidation. Here, oxygen transfer from AgO x to Pd and the surface reactivity toward CO were investigated as a function of the Pd coverage using X-ray photoelectron spectroscopy, surface infrared spectroscopy of adsorbed CO, temperature-programmed reaction spectroscopy, and density functional theory (DFT) calculations. Our results show that all of the oxygen from the AgO x layer (~0.375 monolayer) migrates to the surface of Pd during formation of a nearly complete Pd bilayer at 300 K and that the oxygen coverages generated on Pd increase as the Pd cluster size decreases, reaching values that exceed the oxygen concentration in the AgO x layer by as much as a factor of 2. Experimental measurements and DFT calculations show that preferential binding of oxygen on the edges of the Pd clusters enhances the oxygen coverage on Pd clusters of decreasing size and produces a heterogeneous spatial distribution of oxygen. CO adsorbs in high coverages at 100 K by binding on both the terraces and O-rich edges of the Pd clusters. During subsequent heating, oxidation of the adsorbed CO consumes nearly all of the oxygen that transferred from AgO x to the Pd domains; in contrast, the pure AgO x layer exhibits limited reactivity toward CO adsorbed at 100 K. These results demonstrate that differences in oxophilicity drive facile oxygen transfer from Ag to the edges of Pd nanoclusters and thereby give rise to an efficient pathway for CO oxidation on bimetallic PdAg surfaces. The cooperation between the Pd and Ag domains results in near-interfacial chemistry that may be broadly important in catalysis by bimetallic alloys.

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

Materials Data on K2O by Materials Project

K2O is Hydrophilite-like structured and crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. K1+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. There are two shorter (2.68 Å) and one longer (2.71 Å) K–O bond lengths. O2- is bonded to six equivalent K1+ atoms to form a mixture of edge and corner-sharing OK6 octahedra. The corner-sharing octahedral tilt angles are 53°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2GeSe3 by Materials Project

K2GeSe3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six Se2- atoms to form KSe6 octahedra that share corners with two equivalent KSe6 octahedra, corners with three equivalent GeSe4 tetrahedra, edges with three equivalent KSe6 octahedra, and edges with two equivalent GeSe4 tetrahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of K–Se bond distances ranging from 3.35–3.53 Å. In the second K1+ site, K1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of K–Se bond distances ranging from 3.37–3.77 Å. Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share corners with three equivalent KSe6 octahedra, edges with two equivalent KSe6 octahedra, and an edgeedge with one GeSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 18–87°. There are a spread of Ge–Se bond distances ranging from 2.33–2.49 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to five K1+ and one Ge4+ atom to form a mixture of distorted edge and corner-sharing SeK5Ge octahedra. The corner-sharing octahedra tilt angles range from 5–65°. In the second Se2- site, Se2- is bonded to five K1+ and one Ge4+ atom to form a mixture of distorted edge and corner-sharing SeK5Ge octahedra. The corner-sharing octahedra tilt angles range from 5–65°. In the third Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two K1+ and two equivalent Ge4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2TeO5 by Materials Project

K2TeO5 crystallizes in the orthorhombic Immm space group. The structure is two-dimensional and consists of two K2TeO5 sheets oriented in the (0, 0, 1) direction. there are three inequivalent K sites. In the first K site, K is bonded in a 6-coordinate geometry to four equivalent O atoms. All K–O bond lengths are 2.78 Å. In the second K site, K is bonded in a 4-coordinate geometry to four equivalent O atoms. All K–O bond lengths are 2.74 Å. In the third K site, K is bonded in a distorted T-shaped geometry to three O atoms. There are two shorter (2.57 Å) and one longer (2.60 Å) K–O bond lengths. Te is bonded to six O atoms to form edge-sharing TeO6 octahedra. There are a spread of Te–O bond distances ranging from 1.90–2.04 Å. There are five inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Te atom. In the second O site, O is bonded in a 1-coordinate geometry to three K and one Te atom. In the third O site, O is bonded in a water-like geometry to two equivalent Te atoms. In the fourth O site, O is bonded in a water-like geometry to two equivalent Te atoms. In the fifth O site, O is bonded in a bent 150 degrees geometry to one K and one Te atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2U2O7 by Materials Project

K2U2O7 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six O2- atoms to form KO6 octahedra that share corners with six UO6 octahedra and edges with six KO6 octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of K–O bond distances ranging from 2.71–2.83 Å. In the second K1+ site, K1+ is bonded to six O2- atoms to form distorted KO6 octahedra that share corners with six UO6 octahedra and edges with six KO6 octahedra. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of K–O bond distances ranging from 2.71–2.86 Å. There are two inequivalent U6+ sites. In the first U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with five UO6 octahedra, corners with six KO6 octahedra, and an edgeedge with one UO6 octahedra. The corner-sharing octahedra tilt angles range from 9–59°. There are a spread of U–O bond distances ranging from 1.88–2.32 Å. In the second U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with five UO6 octahedra, corners with six KO6 octahedra, and an edgeedge with one UO6 octahedra. The corner-sharing octahedra tilt angles range from 9–59°. There are a spread of U–O bond distances ranging from 1.89–2.28 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two U6+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three K1+ and one U6+ atom. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three K1+ and one U6+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three K1+ and one U6+ atom. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to three U6+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three U6+ atoms. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three K1+ and one U6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K8SnSb4 by Materials Project

K8SnSb4 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six equivalent Sb3- atoms to form distorted KSb6 octahedra that share corners with eighteen equivalent KSb4 tetrahedra, edges with six equivalent KSb6 octahedra, faces with two equivalent SnSb4 tetrahedra, and faces with six equivalent KSb4 tetrahedra. All K–Sb bond lengths are 3.80 Å. In the second K1+ site, K1+ is bonded to four equivalent Sb3- atoms to form distorted KSb4 tetrahedra that share corners with six equivalent KSb6 octahedra, corners with two equivalent SnSb4 tetrahedra, corners with twelve equivalent KSb4 tetrahedra, an edgeedge with one SnSb4 tetrahedra, edges with four equivalent KSb4 tetrahedra, and faces with two equivalent KSb6 octahedra. The corner-sharing octahedra tilt angles range from 33–51°. There are two shorter (3.68 Å) and two longer (3.69 Å) K–Sb bond lengths. Sn4+ is bonded to four equivalent Sb3- atoms to form SnSb4 tetrahedra that share corners with twelve equivalent KSb4 tetrahedra, edges with six equivalent KSb4 tetrahedra, and faces with four equivalent KSb6 octahedra. All Sn–Sb bond lengths are 2.95 Å. Sb3- is bonded in a 10-coordinate geometry to nine K1+ and one Sn4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KMg6Ti by Materials Project

KMg6Ti crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. K is bonded to ten Mg and two equivalent Ti atoms to form KMg10Ti2 cuboctahedra that share corners with four equivalent MgK2Mg10 cuboctahedra, corners with six equivalent KMg10Ti2 cuboctahedra, edges with two equivalent MgK2Mg10 cuboctahedra, edges with four equivalent TiK2Mg10 cuboctahedra, faces with two equivalent KMg10Ti2 cuboctahedra, faces with two equivalent TiK2Mg10 cuboctahedra, and faces with eight MgMg10Ti2 cuboctahedra. There are a spread of K–Mg bond distances ranging from 3.26–3.38 Å. Both K–Ti bond lengths are 3.47 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a 3-coordinate geometry to two equivalent K, six Mg, and two equivalent Ti atoms. There are a spread of Mg–Mg bond distances ranging from 3.23–3.31 Å. There are one shorter (3.02 Å) and one longer (3.54 Å) Mg–Ti bond lengths. In the second Mg site, Mg is bonded to ten Mg and two equivalent Ti atoms to form MgMg10Ti2 cuboctahedra that share corners with four equivalent TiK2Mg10 cuboctahedra, corners with six equivalent MgMg10Ti2 cuboctahedra, edges with two equivalent TiK2Mg10 cuboctahedra, edges with four equivalent MgK2Mg10 cuboctahedra, faces with two equivalent TiK2Mg10 cuboctahedra, faces with four MgMg10Ti2 cuboctahedra, and faces with six equivalent KMg10Ti2 cuboctahedra. There are two shorter (3.27 Å) and four longer (3.30 Å) Mg–Mg bond lengths. Both Mg–Ti bond lengths are 3.38 Å. In the third Mg site, Mg is bonded in a 11-coordinate geometry to two equivalent K, seven Mg, and two equivalent Ti atoms. There are a spread of Mg–Mg bond distances ranging from 3.08–3.29 Å. Both Mg–Ti bond lengths are 3.11 Å. In the fourth Mg site, Mg is bonded to two equivalent K and ten Mg atoms to form distorted MgK2Mg10 cuboctahedra that share corners with four equivalent KMg10Ti2 cuboctahedra, corners with six equivalent MgK2Mg10 cuboctahedra, edges with two equivalent KMg10Ti2 cuboctahedra, edges with four equivalent MgMg10Ti2 cuboctahedra, faces with two equivalent KMg10Ti2 cuboctahedra, faces with four MgMg10Ti2 cuboctahedra, and faces with six equivalent TiK2Mg10 cuboctahedra. Ti is bonded to two equivalent K and ten Mg atoms to form TiK2Mg10 cuboctahedra that share corners with four equivalent MgMg10Ti2 cuboctahedra, corners with six equivalent TiK2Mg10 cuboctahedra, edges with two equivalent MgMg10Ti2 cuboctahedra, edges with four equivalent KMg10Ti2 cuboctahedra, faces with two equivalent KMg10Ti2 cuboctahedra, faces with two equivalent TiK2Mg10 cuboctahedra, and faces with eight MgMg10Ti2 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3GeS3 by Materials Project

K3GeS3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of K–S bond distances ranging from 3.27–3.43 Å. In the second K1+ site, K1+ is bonded to six S2- atoms to form a mixture of distorted corner and edge-sharing KS6 octahedra. The corner-sharing octahedral tilt angles are 41°. There are a spread of K–S bond distances ranging from 3.22–3.57 Å. In the third K1+ site, K1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of K–S bond distances ranging from 3.18–3.40 Å. Ge3+ is bonded in a trigonal non-coplanar geometry to three S2- atoms. All Ge–S bond lengths are 2.25 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 7-coordinate geometry to six K1+ and one Ge3+ atom. In the second S2- site, S2- is bonded in a 7-coordinate geometry to six K1+ and one Ge3+ atom.

36 MATERIALS SCIENCE↗