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DOE OSTI2020

Materials Data on K2Ag4Se3 by Materials Project

K2Ag4Se3 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 Se2- atoms to form a mixture of edge, face, and corner-sharing KSe6 octahedra. The corner-sharing octahedra tilt angles range from 41–60°. There are a spread of K–Se bond distances ranging from 3.45–3.51 Å. In the second K1+ site, K1+ is bonded to six Se2- atoms to form a mixture of edge, face, and corner-sharing KSe6 octahedra. The corner-sharing octahedra tilt angles range from 41–60°. There are a spread of K–Se bond distances ranging from 3.33–3.49 Å. There are four inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a distorted trigonal non-coplanar geometry to three Se2- atoms. There are two shorter (2.68 Å) and one longer (2.74 Å) Ag–Se bond lengths. In the second Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to four Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.65–3.23 Å. In the third Ag1+ site, Ag1+ is bonded in a distorted trigonal non-coplanar geometry to three Se2- atoms. There are one shorter (2.67 Å) and two longer (2.80 Å) Ag–Se bond lengths. In the fourth Ag1+ site, Ag1+ is bonded in a distorted trigonal planar geometry to three Se2- atoms. There are two shorter (2.60 Å) and one longer (2.77 Å) Ag–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 7-coordinate geometry to four K1+ and four Ag1+ atoms. In the second Se2- site, Se2- is bonded in a 8-coordinate geometry to five K1+ and three Ag1+ atoms. In the third Se2- site, Se2- is bonded in a 9-coordinate geometry to three K1+ and six Ag1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Fungal organic acid uptake of mineral-derived K is dependent on distance from carbon hotspot

Fungal mineral weathering regulates the bioavailability of inorganic nutrients from mineral surfaces to organic matter and increase the bioavailable fraction of nutrients. Such weathering strategies are classified as biomechanical or biochemical. In the case of fungal uptake of mineral nutrients through biochemical weathering, it is widely hypothesized that uptake of inorganic nutrients occurs through organic acid chelation, but such processes have not been directly visualized. This is in part due to challenges in probing the complex and heterogeneous soil environment. Here, using an epoxy-based, mineral-doped soil micromodel platform, which emulates soil mineralogy and porosity, we visualize the molecular mechanisms of mineral weathering. Mass spectrometry imaging revealed differences in the distribution of fungal exudates, citric acid, and tartaric acid on the soil micromodels in presence of minerals. Citric acid was detected closer to the nutrient-rich inoculation point, whereas tartaric acid was highly abundant away from inoculation point. This suggested that the organic acid exuded by the fungi depended on the proximity from the carbon-rich organic substrate at the point of inoculation. Using a combination of X-ray fluorescence and X-ray near edge structure analysis, we identified citric acid- and tartaric acid-bound K within fungal hyphae networks grown in the presence of minerals. Combined, our results provide direct evidence that fungi uptake and transport mineral derived nutrient organic acid chelation. The results of this study provided unprecedented visualization of fungal uptake and transport of K + , while resolving the indirect weathering mechanism of fungal K uptake from mineral interfaces.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Materials Data on K9Bi5O13 by Materials Project

K9Bi5O13 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are nine 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 KO6 octahedra, a cornercorner with one KO5 square pyramid, a cornercorner with one BiO4 tetrahedra, a cornercorner with one KO5 trigonal bipyramid, edges with five KO6 octahedra, edges with two equivalent KO5 square pyramids, edges with two equivalent BiO4 tetrahedra, and an edgeedge with one KO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 13°. There are a spread of K–O bond distances ranging from 2.72–3.02 Å. In the second K1+ site, K1+ is bonded to five O2- atoms to form distorted KO5 trigonal bipyramids that share corners with two KO6 octahedra, a cornercorner with one BiO4 tetrahedra, corners with two equivalent KO5 trigonal bipyramids, and edges with two equivalent KO6 octahedra. The corner-sharing octahedra tilt angles range from 37–44°. There are a spread of K–O bond distances ranging from 2.63–3.01 Å. In the third K1+ site, K1+ is bonded to five O2- atoms to form distorted KO5 square pyramids that share a cornercorner with one KO6 octahedra, corners with two equivalent KO5 square pyramids, a cornercorner with one BiO4 tetrahedra, corners with three equivalent KO5 trigonal bipyramids, and edges with four KO6 octahedra. The corner-sharing octahedral tilt angles are 9°. There are a spread of K–O bond distances ranging from 2.68–2.93 Å. In the fourth K1+ site, K1+ is bonded to six O2- atoms to form distorted KO6 octahedra that share corners with three KO6 octahedra, a cornercorner with one KO5 trigonal bipyramid, an edgeedge with one KO5 square pyramid, and edges with three KO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 19–35°. There are a spread of K–O bond distances ranging from 2.73–3.00 Å. In the fifth K1+ site, K1+ is bonded to five O2- atoms to form distorted KO5 trigonal bipyramids that share a cornercorner with one KO6 octahedra, corners with three equivalent KO5 square pyramids, corners with two equivalent BiO4 tetrahedra, a cornercorner with one KO5 trigonal bipyramid, edges with two KO6 octahedra, and an edgeedge with one KO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 27°. There are a spread of K–O bond distances ranging from 2.68–2.85 Å. In the sixth K1+ site, K1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 2.70–3.13 Å. In the seventh K1+ site, K1+ is bonded to five O2- atoms to form distorted KO5 trigonal bipyramids that share a cornercorner with one BiO4 tetrahedra, corners with three KO5 trigonal bipyramids, edges with two equivalent KO6 octahedra, and an edgeedge with one KO5 trigonal bipyramid. There are a spread of K–O bond distances ranging from 2.60–2.99 Å. In the eighth K1+ site, K1+ is bonded to six O2- atoms to form distorted KO6 octahedra that share corners with three KO6 octahedra, corners with two equivalent BiO4 tetrahedra, a cornercorner with one KO5 trigonal bipyramid, edges with three equivalent KO6 octahedra, an edgeedge with one KO5 square pyramid, an edgeedge with one BiO4 tetrahedra, and edges with two equivalent KO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 29–35°. There are a spread of K–O bond distances ranging from 2.73–3.29 Å. In the ninth K1+ site, K1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of K–O bond distances ranging from 2.69–3.05 Å. There are five inequivalent Bi+3.40+ sites. In the first Bi+3.40+ site, Bi+3.40+ is bonded in a see-saw-like geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.10–2.43 Å. In the second Bi+3.40+ site, Bi+3.40+ is bonded to four O2- atoms to form BiO4 tetrahedra that share corners with three KO6 octahedra, a cornercorner with one KO5 square pyramid, corners with four KO5 trigonal bipyramids, and edges with three KO6 octahedra. The corner-sharing octahedra tilt angles range from 11–75°. There are two shorter (2.04 Å) and two longer (2.05 Å) Bi–O bond lengths. In the third Bi+3.40+ site, Bi+3.40+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.06–2.69 Å. In the fourth Bi+3.40+ site, Bi+3.40+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.09–2.91 Å. In the fifth Bi+3.40+ site, Bi+3.40+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.07–2.40 Å. There are thirteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to four K1+ and two Bi+3.40+ atoms. In the second O2- site, O2- is bonded to five K1+ and one Bi+3.40+ atom to form distorted OK5Bi octahedra that share corners with four OK5Bi octahedra, corners with two OK4Bi trigonal bipyramids, edges with four OK5Bi octahedra, and edges with two equivalent OK4Bi trigonal bipyramids. The corner-sharing octahedra tilt angles range from 3–13°. In the third O2- site, O2- is bonded in a 5-coordinate geometry to four K1+ and one Bi+3.40+ atom. In the fourth O2- site, O2- is bonded to four K1+ and two Bi+3.40+ atoms to form distorted OK4Bi2 octahedra that share corners with four OK5Bi octahedra, a cornercorner with one OK3Bi2 trigonal bipyramid, edges with two equivalent OK5Bi octahedra, an edgeedge with one OK3Bi2 square pyramid, and edges with three OK4Bi trigonal bipyramids. The corner-sharing octahedra tilt angles range from 5–12°. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three K1+ and one Bi+3.40+ atom. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to three K1+ and two Bi+3.40+ atoms. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to two K1+ and three Bi+3.40+ atoms. In the eighth O2- site, O2- is bonded to four K1+ and one Bi+3.40+ atom to form distorted OK4Bi trigonal bipyramids that share a cornercorner with one OK5Bi octahedra, a cornercorner with one OK3Bi2 trigonal bipyramid, and edges with five OK5Bi octahedra. The corner-sharing octahedral tilt angles are 82°. In the ninth O2- site, O2- is bonded to five K1+ and one Bi+3.40+ atom to form distorted OK5Bi octahedra that share corners with four OK5Bi octahedra and an edgeedge with one OK4Bi trigonal bipyramid. The corner-sharing octahedra tilt angles range from 3–27°. In the tenth O2- site, O2- is bonded to three K1+ and two Bi+3.40+ atoms to form distorted OK3Bi2 square pyramids that share corners with two equivalent OK3Bi2 square pyramids, corners with two equivalent OK3Bi2 trigonal bipyramids, edges with three OK5Bi octahedra, and an edgeedge with one OK3Bi2 trigonal bipyramid. In the eleventh O2- site, O2- is bonded to five K1+ and one Bi+3.40+ atom to form distorted OK5Bi octahedra that share corners with four OK5Bi octahedra, edges with two equivalent OK3Bi2 square pyramids, and edges with two OK4Bi trigonal bipyramids. The corner-sharing octahedra tilt angles range from 12–27°. In the twelfth O2- site, O2- is bonded in a 5-coordinate geometry to four K1+ and one Bi+3.40+ atom. In the thirteenth O2- site, O2- is bonded to three K1+ and two equivalent Bi+3.40+ atoms to form distorted OK3Bi2 trigonal bipyramids that share corners with two OK5Bi octahedra, corners with two equivalent OK3Bi2 square pyramids, a cornercorner with one OK4Bi trigonal bipyramid, edges with three OK5Bi octahedra, an edgeedge with one OK3Bi2 square pyramid, and an edgeedge with one OK3Bi2 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 19–80°.

36 MATERIALS SCIENCE↗
NASA NTRS1993

Hypersonic engine component experiments in high heat flux, supersonic flow environment

A major concern in advancing the state-of-the-art technologies for hypersonic vehicles is the development of an aeropropulsion system capable of withstanding the sustained high thermal loads expected during hypersonic flight. Even though progress has been made in the computational understanding of fluid dynamics and the physics/chemistry of high speed flight, there is also a need for experimental facilities capable of providing a high heat flux environment for testing component concepts and verifying/calibrating these analyses. A hydrogen/oxygen rocket engine heat source was developed at the NASA Lewis Research Center as one element in a series of facilities at national laboratories designed to fulfill this need. This 'Hot Gas Facility' is capable of providing heat fluxes up to 450 w/sq cm on flat surfaces and up to 5,000 w/sq cm at the leading edge stagnation point of a strut in a supersonic flow stream. Gas temperatures up to 3050 K can also be attained. Two recent experimental programs conducted in this facility are discussed. The objective of the first experiment is to evaluate the erosion and oxidation characteristics of a coating on a cowl leading edge (or strut leading edge) in a supersonic, high heat flux environment. Macrophotographic data from a coated leading edge model show progressive degradation over several thermal cycles at aerothermal conditions representative of high Mach number flight. The objective of the second experiment is to assess the capability of cooling a porous surface exposed to a high temperature, high velocity flow environment and to provide a heat transfer data base for a design procedure. Experimental results from transpiration cooled surfaces in a supersonic flow environment are presented.

Gladden, Herbert J.↗
DOE OSTI2020

Materials Data on K2VCuS4 by Materials Project

K2VCuS4 crystallizes in the orthorhombic Fddd 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 two equivalent VS4 tetrahedra, corners with four equivalent CuS4 tetrahedra, edges with six equivalent KS8 hexagonal bipyramids, edges with two equivalent CuS4 tetrahedra, edges with three equivalent VS4 tetrahedra, and faces with two equivalent KS8 hexagonal bipyramids. There are a spread of K–S bond distances ranging from 3.32–3.52 Å. V5+ is bonded to four equivalent S2- atoms to form VS4 tetrahedra that share corners with four equivalent KS8 hexagonal bipyramids, edges with six equivalent KS8 hexagonal bipyramids, and edges with two equivalent CuS4 tetrahedra. All V–S bond lengths are 2.18 Å. Cu1+ is bonded to four equivalent S2- atoms to form CuS4 tetrahedra that share corners with eight equivalent KS8 hexagonal bipyramids, edges with four equivalent KS8 hexagonal bipyramids, and edges with two equivalent VS4 tetrahedra. All Cu–S bond lengths are 2.31 Å. S2- is bonded in a 6-coordinate geometry to four equivalent K1+, one V5+, and one Cu1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2VCuSe4 by Materials Project

K2VCuSe4 crystallizes in the orthorhombic Fddd 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 two equivalent VSe4 tetrahedra, corners with four equivalent CuSe4 tetrahedra, edges with six equivalent KSe8 hexagonal bipyramids, edges with two equivalent CuSe4 tetrahedra, edges with three equivalent VSe4 tetrahedra, and faces with two equivalent KSe8 hexagonal bipyramids. There are a spread of K–Se bond distances ranging from 3.42–3.64 Å. V5+ is bonded to four equivalent Se2- atoms to form VSe4 tetrahedra that share corners with four equivalent KSe8 hexagonal bipyramids, edges with six equivalent KSe8 hexagonal bipyramids, and edges with two equivalent CuSe4 tetrahedra. All V–Se bond lengths are 2.32 Å. Cu1+ is bonded to four equivalent Se2- atoms to form CuSe4 tetrahedra that share corners with eight equivalent KSe8 hexagonal bipyramids, edges with four equivalent KSe8 hexagonal bipyramids, and edges with two equivalent VSe4 tetrahedra. All Cu–Se bond lengths are 2.43 Å. Se2- is bonded in a 6-coordinate geometry to four equivalent K1+, one V5+, and one Cu1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2TaCuSe4 by Materials Project

K2TaCuSe4 crystallizes in the orthorhombic Fddd 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 two equivalent TaSe4 tetrahedra, corners with four equivalent CuSe4 tetrahedra, edges with six equivalent KSe8 hexagonal bipyramids, edges with two equivalent CuSe4 tetrahedra, edges with three equivalent TaSe4 tetrahedra, and faces with two equivalent KSe8 hexagonal bipyramids. There are a spread of K–Se bond distances ranging from 3.52–3.72 Å. Ta5+ is bonded to four equivalent Se2- atoms to form TaSe4 tetrahedra that share corners with four equivalent KSe8 hexagonal bipyramids, edges with six equivalent KSe8 hexagonal bipyramids, and edges with two equivalent CuSe4 tetrahedra. All Ta–Se bond lengths are 2.43 Å. Cu1+ is bonded to four equivalent Se2- atoms to form CuSe4 tetrahedra that share corners with eight equivalent KSe8 hexagonal bipyramids, edges with four equivalent KSe8 hexagonal bipyramids, and edges with two equivalent TaSe4 tetrahedra. All Cu–Se bond lengths are 2.47 Å. Se2- is bonded in a 6-coordinate geometry to four equivalent K1+, one Ta5+, and one Cu1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2NbCuSe4 by Materials Project

K2NbCuSe4 crystallizes in the orthorhombic Fddd 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 two equivalent NbSe4 tetrahedra, corners with four equivalent CuSe4 tetrahedra, edges with six equivalent KSe8 hexagonal bipyramids, edges with two equivalent CuSe4 tetrahedra, edges with three equivalent NbSe4 tetrahedra, and faces with two equivalent KSe8 hexagonal bipyramids. There are a spread of K–Se bond distances ranging from 3.53–3.71 Å. Nb5+ is bonded to four equivalent Se2- atoms to form NbSe4 tetrahedra that share corners with four equivalent KSe8 hexagonal bipyramids, edges with six equivalent KSe8 hexagonal bipyramids, and edges with two equivalent CuSe4 tetrahedra. All Nb–Se bond lengths are 2.43 Å. Cu1+ is bonded to four equivalent Se2- atoms to form CuSe4 tetrahedra that share corners with eight equivalent KSe8 hexagonal bipyramids, edges with four equivalent KSe8 hexagonal bipyramids, and edges with two equivalent NbSe4 tetrahedra. All Cu–Se bond lengths are 2.47 Å. Se2- is bonded in a 6-coordinate geometry to four equivalent K1+, one Nb5+, and one Cu1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2NbCuS4 by Materials Project

K2NbCuS4 crystallizes in the orthorhombic Fddd 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 two equivalent NbS4 tetrahedra, corners with four equivalent CuS4 tetrahedra, edges with six equivalent KS8 hexagonal bipyramids, edges with two equivalent CuS4 tetrahedra, edges with three equivalent NbS4 tetrahedra, and faces with two equivalent KS8 hexagonal bipyramids. There are a spread of K–S bond distances ranging from 3.43–3.59 Å. Nb5+ is bonded to four equivalent S2- atoms to form NbS4 tetrahedra that share corners with four equivalent KS8 hexagonal bipyramids, edges with six equivalent KS8 hexagonal bipyramids, and edges with two equivalent CuS4 tetrahedra. All Nb–S bond lengths are 2.30 Å. Cu1+ is bonded to four equivalent S2- atoms to form CuS4 tetrahedra that share corners with eight equivalent KS8 hexagonal bipyramids, edges with four equivalent KS8 hexagonal bipyramids, and edges with two equivalent NbS4 tetrahedra. All Cu–S bond lengths are 2.35 Å. S2- is bonded in a 6-coordinate geometry to four equivalent K1+, one Nb5+, and one Cu1+ atom.

36 MATERIALS SCIENCE↗
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↗