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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Nb5(SeS)2 by Materials Project

Nb5(SeS)2 is Titanium telluride-derived structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Nb sites. In the first Nb site, Nb is bonded in a distorted square co-planar geometry to two equivalent Se and two equivalent S atoms. Both Nb–Se bond lengths are 2.88 Å. Both Nb–S bond lengths are 2.73 Å. In the second Nb site, Nb is bonded to two equivalent Se and three equivalent S atoms to form distorted NbSe2S3 square pyramids that share corners with eight equivalent NbSe3S2 square pyramids and edges with six NbSe2S3 square pyramids. Both Nb–Se bond lengths are 2.66 Å. There are one shorter (2.50 Å) and two longer (2.59 Å) Nb–S bond lengths. In the third Nb site, Nb is bonded to three equivalent Se and two equivalent S atoms to form a mixture of distorted edge and corner-sharing NbSe3S2 square pyramids. There are one shorter (2.63 Å) and two longer (2.72 Å) Nb–Se bond lengths. Both Nb–S bond lengths are 2.54 Å. Se is bonded in a 6-coordinate geometry to six Nb atoms. S is bonded in a 6-coordinate geometry to six Nb atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd4Ge(SeS)3 by Materials Project

Cd4Ge(SeS)3 is Chalcostibite-derived structured and crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are four inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to three Se2- and one S2- atom to form CdSe3S tetrahedra that share corners with two equivalent GeSeS3 tetrahedra, corners with six CdSe3S tetrahedra, and corners with two equivalent CdSe2S2 trigonal pyramids. There are a spread of Cd–Se bond distances ranging from 2.67–2.71 Å. The Cd–S bond length is 2.66 Å. In the second Cd2+ site, Cd2+ is bonded to three Se2- and one S2- atom to form CdSe3S tetrahedra that share corners with two equivalent GeSeS3 tetrahedra, corners with five CdSe3S tetrahedra, and corners with three equivalent CdSe2S2 trigonal pyramids. There are two shorter (2.68 Å) and one longer (2.75 Å) Cd–Se bond lengths. The Cd–S bond length is 2.60 Å. In the third Cd2+ site, Cd2+ is bonded to two Se2- and two S2- atoms to form distorted CdSe2S2 trigonal pyramids that share corners with two equivalent GeSeS3 tetrahedra and corners with eight CdSe3S tetrahedra. There are one shorter (2.69 Å) and one longer (2.72 Å) Cd–Se bond lengths. There are one shorter (2.59 Å) and one longer (2.74 Å) Cd–S bond lengths. In the fourth Cd2+ site, Cd2+ is bonded to two Se2- and two S2- atoms to form CdSe2S2 tetrahedra that share corners with two equivalent GeSeS3 tetrahedra, corners with five CdSe3S tetrahedra, and corners with three equivalent CdSe2S2 trigonal pyramids. There are one shorter (2.69 Å) and one longer (2.73 Å) Cd–Se bond lengths. There are one shorter (2.60 Å) and one longer (2.61 Å) Cd–S bond lengths. Ge4+ is bonded to one Se2- and three S2- atoms to form GeSeS3 tetrahedra that share corners with six CdSe3S tetrahedra and corners with two equivalent CdSe2S2 trigonal pyramids. The Ge–Se bond length is 2.37 Å. There are two shorter (2.23 Å) and one longer (2.25 Å) Ge–S bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four Cd2+ atoms to form corner-sharing SeCd4 tetrahedra. In the second Se2- site, Se2- is bonded to four Cd2+ atoms to form corner-sharing SeCd4 tetrahedra. In the third Se2- site, Se2- is bonded in a distorted trigonal non-coplanar geometry to two Cd2+ and one Ge4+ atom. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted trigonal non-coplanar geometry to two Cd2+ and one Ge4+ atom. In the second S2- site, S2- is bonded in a distorted trigonal non-coplanar geometry to two Cd2+ and one Ge4+ atom. In the third S2- site, S2- is bonded in a trigonal non-coplanar geometry to two Cd2+ and one Ge4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VCu3(SeS)2 by Materials Project

VCu3(SeS)2 is Stannite-like structured and crystallizes in the orthorhombic Cmm2 space group. The structure is three-dimensional. V5+ is bonded to two equivalent Se2- and two equivalent S2- atoms to form VSe2S2 tetrahedra that share edges with six CuSe2S2 tetrahedra. Both V–Se bond lengths are 2.35 Å. Both V–S bond lengths are 2.22 Å. There are two inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to two equivalent Se2- and two equivalent S2- atoms to form CuSe2S2 tetrahedra that share corners with eight CuSe2S2 tetrahedra and edges with two equivalent VSe2S2 tetrahedra. Both Cu–Se bond lengths are 2.43 Å. Both Cu–S bond lengths are 2.28 Å. In the second Cu1+ site, Cu1+ is bonded to two equivalent Se2- and two equivalent S2- atoms to form CuSe2S2 tetrahedra that share corners with eight equivalent CuSe2S2 tetrahedra and edges with two equivalent VSe2S2 tetrahedra. Both Cu–Se bond lengths are 2.41 Å. Both Cu–S bond lengths are 2.30 Å. Se2- is bonded to one V5+ and three Cu1+ atoms to form distorted SeVCu3 tetrahedra that share corners with two equivalent SeVCu3 tetrahedra, corners with four equivalent SVCu3 tetrahedra, an edgeedge with one SeVCu3 tetrahedra, and edges with two equivalent SVCu3 tetrahedra. S2- is bonded to one V5+ and three Cu1+ atoms to form distorted SVCu3 tetrahedra that share corners with two equivalent SVCu3 tetrahedra, corners with four equivalent SeVCu3 tetrahedra, an edgeedge with one SVCu3 tetrahedra, and edges with two equivalent SeVCu3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr4(SeS)3 by Materials Project

Cr4(SeS)3 is Ilmenite-like structured and crystallizes in the trigonal R3 space group. The structure is three-dimensional. there are four inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to three equivalent Se2- and three equivalent S2- atoms to form a mixture of corner and edge-sharing CrSe3S3 octahedra. The corner-sharing octahedra tilt angles range from 46–48°. All Cr–Se bond lengths are 2.52 Å. All Cr–S bond lengths are 2.41 Å. In the second Cr3+ site, Cr3+ is bonded to three equivalent Se2- and three equivalent S2- atoms to form a mixture of corner and face-sharing CrSe3S3 octahedra. The corner-sharing octahedra tilt angles range from 46–50°. All Cr–Se bond lengths are 2.56 Å. All Cr–S bond lengths are 2.36 Å. In the third Cr3+ site, Cr3+ is bonded to three equivalent Se2- and three equivalent S2- atoms to form a mixture of corner, edge, and face-sharing CrSe3S3 octahedra. The corner-sharing octahedral tilt angles are 50°. All Cr–Se bond lengths are 2.54 Å. All Cr–S bond lengths are 2.42 Å. In the fourth Cr3+ site, Cr3+ is bonded to three equivalent Se2- and three equivalent S2- atoms to form a mixture of corner, edge, and face-sharing CrSe3S3 octahedra. The corner-sharing octahedral tilt angles are 48°. All Cr–Se bond lengths are 2.52 Å. All Cr–S bond lengths are 2.35 Å. Se2- is bonded in a rectangular see-saw-like geometry to four Cr3+ atoms. S2- is bonded in a distorted rectangular see-saw-like geometry to four Cr3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr2Cu(SeS)2 by Materials Project

Cr2Cu(SeS)2 is Spinel-derived structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Cr3+ is bonded to three equivalent Se2- and three equivalent S2- atoms to form CrSe3S3 octahedra that share corners with six CuS4 tetrahedra and edges with six equivalent CrSe3S3 octahedra. All Cr–Se bond lengths are 2.53 Å. All Cr–S bond lengths are 2.39 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to four equivalent S2- atoms to form CuS4 tetrahedra that share corners with twelve equivalent CrSe3S3 octahedra. The corner-sharing octahedral tilt angles are 55°. All Cu–S bond lengths are 2.33 Å. In the second Cu2+ site, Cu2+ is bonded to four equivalent Se2- atoms to form CuSe4 tetrahedra that share corners with twelve equivalent CrSe3S3 octahedra. The corner-sharing octahedral tilt angles are 60°. All Cu–Se bond lengths are 2.35 Å. Se2- is bonded to three equivalent Cr3+ and one Cu2+ atom to form a mixture of distorted edge and corner-sharing SeCr3Cu tetrahedra. S2- is bonded in a rectangular see-saw-like geometry to three equivalent Cr3+ and one Cu2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaCu3(SeS)2 by Materials Project

TaCu3(SeS)2 is Stannite-like structured and crystallizes in the orthorhombic Cmm2 space group. The structure is three-dimensional. Ta5+ is bonded to two equivalent Se2- and two equivalent S2- atoms to form TaSe2S2 tetrahedra that share edges with six CuSe2S2 tetrahedra. Both Ta–Se bond lengths are 2.46 Å. Both Ta–S bond lengths are 2.33 Å. There are two inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to two equivalent Se2- and two equivalent S2- atoms to form CuSe2S2 tetrahedra that share corners with eight CuSe2S2 tetrahedra and edges with two equivalent TaSe2S2 tetrahedra. Both Cu–Se bond lengths are 2.50 Å. Both Cu–S bond lengths are 2.35 Å. In the second Cu1+ site, Cu1+ is bonded to two equivalent Se2- and two equivalent S2- atoms to form CuSe2S2 tetrahedra that share corners with eight equivalent CuSe2S2 tetrahedra and edges with two equivalent TaSe2S2 tetrahedra. Both Cu–Se bond lengths are 2.47 Å. Both Cu–S bond lengths are 2.37 Å. Se2- is bonded to one Ta5+ and three Cu1+ atoms to form distorted SeTaCu3 tetrahedra that share corners with two equivalent SeTaCu3 tetrahedra, corners with four equivalent STaCu3 tetrahedra, an edgeedge with one SeTaCu3 tetrahedra, and edges with two equivalent STaCu3 tetrahedra. S2- is bonded to one Ta5+ and three Cu1+ atoms to form distorted STaCu3 tetrahedra that share corners with two equivalent STaCu3 tetrahedra, corners with four equivalent SeTaCu3 tetrahedra, an edgeedge with one STaCu3 tetrahedra, and edges with two equivalent SeTaCu3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mo3(SeS)2 by Materials Project

Mo3(SeS)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Mo+2.67+ sites. In the first Mo+2.67+ site, Mo+2.67+ is bonded to three Se2- and two S2- atoms to form a mixture of corner and edge-sharing MoSe3S2 square pyramids. All Mo–Se bond lengths are 2.56 Å. There are one shorter (2.43 Å) and one longer (2.44 Å) Mo–S bond lengths. In the second Mo+2.67+ site, Mo+2.67+ is bonded to two Se2- and three S2- atoms to form a mixture of corner and edge-sharing MoSe2S3 square pyramids. Both Mo–Se bond lengths are 2.57 Å. There are a spread of Mo–S bond distances ranging from 2.43–2.45 Å. In the third Mo+2.67+ site, Mo+2.67+ is bonded to two Se2- and three S2- atoms to form a mixture of corner and edge-sharing MoSe2S3 square pyramids. There are one shorter (2.54 Å) and one longer (2.55 Å) Mo–Se bond lengths. There are one shorter (2.44 Å) and two longer (2.45 Å) Mo–S bond lengths. In the fourth Mo+2.67+ site, Mo+2.67+ is bonded to two Se2- and three S2- atoms to form MoSe2S3 square pyramids that share corners with four MoSe2S3 square pyramids and edges with five MoSe3S2 square pyramids. There are one shorter (2.57 Å) and one longer (2.61 Å) Mo–Se bond lengths. There are two shorter (2.45 Å) and one longer (2.50 Å) Mo–S bond lengths. In the fifth Mo+2.67+ site, Mo+2.67+ is bonded to three Se2- and two S2- atoms to form a mixture of corner and edge-sharing MoSe3S2 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.55–2.61 Å. There are one shorter (2.42 Å) and one longer (2.50 Å) Mo–S bond lengths. In the sixth Mo+2.67+ site, Mo+2.67+ is bonded to two Se2- and three S2- atoms to form a mixture of corner and edge-sharing MoSe2S3 square pyramids. There are one shorter (2.56 Å) and one longer (2.57 Å) Mo–Se bond lengths. There are a spread of Mo–S bond distances ranging from 2.44–2.46 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to four Mo+2.67+ atoms. In the second Se2- site, Se2- is bonded in a 4-coordinate geometry to four Mo+2.67+ atoms. In the third Se2- site, Se2- is bonded in a 6-coordinate geometry to three Mo+2.67+ atoms. In the fourth Se2- site, Se2- is bonded in a 6-coordinate geometry to three Mo+2.67+ atoms. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.67+ atoms. In the second S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.67+ atoms. In the third S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.67+ atoms. In the fourth S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.67+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Electronic and structural properties of RbCe X 2 ( X 2 : O 2 , S 2 , SeS, Se 2 , TeSe, Te 2 )

We report triangular lattice delafossite compounds built from magnetic lanthanide ions are a topic of recent interest due to their frustrated magnetism and realization of quantum disordered magnetic ground states. Here we report the evolution of the structure and electronic ground states of RbCeX 2 compounds, built from a triangular lattice of Ce 3+ ions, upon varying their anion character (X 2 =O 2 , S 2 , SeS, Se 2 , TeSe, Te 2 ). This includes the discovery of a new member of this series, RbCeO 2 , that potentially realizes a quantum disordered ground state analogous to NaYbO 2 . Magnetization and susceptibility measurements reveal that all compounds manifest mean-field antiferromagnetic interactions and, with the exception of the oxide, possess signatures of magnetic correlations onset below 1 K. The crystalline electric field level scheme is explored via neutron scattering and ab initio calculations in order to model the intramultiplet splitting of the J=5/2 multiplet. In addition to the two excited doublets expected within the J=5/2 manifold, we observe one extra local mode present across the sample series. This added mode shifts downward in energy with increasing anion mass and decreasing crystal field strength, suggesting a long-lived anomalous mode endemic to anion motion about the Ce3 + sites.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1971

Variation in spectral irradiance of the SES solar simulator

A test to determine the spectral characteristics of the solar simulation produced by the solar environment simulator (SES) comprised a statistical analysis to determine the spectral variance, and its effect on the average absorptivity of surface coatings.

Mcnutt, A. E.↗
NASA NTRS1978

Orbiter/payload proximity operations SES Postsim report. Lateral approach and other techniques

Various approach and stationkeeping simulations (proximity operations) were conducted in the Shuttle engineering simulator (SES). This simulator is the first to dynamically include the Orbiter reaction control system (RCS) plume effects on a payload being recovered after rendezvous operations. A procedure for braking, using the simultaneous firing of both jets, was evaluated and found very useful for proximity operations. However this procedure is very inefficient in the RCS usage and requires modifications to the digital autopilot (DAP) software. A new final approach, the lateral approach technique (LAT), or the momentum vector proximity approach, was also evaluated in the simulations. The LAT, which included a tailfirst approach for braking, was evaluated successfully with both inertial and gravity stabilized payloads.

Olszewski, O.↗
NASA NTRS1989

STS-32 LDEF Approach in SES

Astronauts Wetherbee, Dunbar, and Low are shown in the Shuttle Engineering Simulator (SES) practicing techniques for approaching the Long Duration Exposure Facility on orbit.

Source record↗
NASA NTRS2011

Systems Engineering Simulator (SES) Simulator Planning Guide

The simulation process, milestones and inputs are unknowns to first-time users of the SES. The Simulator Planning Guide aids in establishing expectations for both NASA and non-NASA facility customers. The potential audience for this guide includes both internal and commercial spaceflight hardware/software developers. It is intended to assist their engineering personnel in simulation planning and execution. Material covered includes a roadmap of the simulation process, roles and responsibilities of facility and user, major milestones, facility capabilities, and inputs required by the facility. Samples of deliverables, facility interfaces, and inputs necessary to define scope, cost, and schedule are included as an appendix to the guide.

McFarlane, Michael↗
DOE OSTI2020

Materials Data on MoW(SeS)2 by Materials Project

MoSe2WS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoSe2 sheet oriented in the (0, 0, 1) direction and one WS2 sheet oriented in the (0, 0, 1) direction. In the MoSe2 sheet, Mo6+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.53 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the WS2 sheet, W2+ is bonded to six equivalent S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.44 Å. S2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MoW(SeS)2 by Materials Project

WSe2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction and one WSe2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo6+ is bonded to six S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. All Mo–S bond lengths are 2.43 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent Mo6+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the WSe2 sheet, W2+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing WSe6 pentagonal pyramids. All W–Se bond lengths are 2.54 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2MoW2(SeS)2 by Materials Project

WTe2WSe2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction; one WSe2 sheet oriented in the (0, 0, 1) direction; and one WTe2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo6+ is bonded to six equivalent S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. All Mo–S bond lengths are 2.46 Å. S2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the WSe2 sheet, W3+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing WSe6 pentagonal pyramids. All W–Se bond lengths are 2.56 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent W3+ atoms. In the WTe2 sheet, W3+ is bonded to six Te2- atoms to form distorted edge-sharing WTe6 pentagonal pyramids. There are three shorter (2.71 Å) and three longer (2.72 Å) W–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent W3+ atoms. In the second Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent W3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2MoW2(SeS)2 by Materials Project

WTe2MoSe2WS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoSe2 sheet oriented in the (0, 0, 1) direction; one WS2 sheet oriented in the (0, 0, 1) direction; and one WTe2 sheet oriented in the (0, 0, 1) direction. In the MoSe2 sheet, Mo6+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.55 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the WS2 sheet, W3+ is bonded to six S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.46 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent W3+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent W3+ atoms. In the WTe2 sheet, W3+ is bonded to six equivalent Te2- atoms to form distorted edge-sharing WTe6 pentagonal pyramids. All W–Te bond lengths are 2.71 Å. Te2- is bonded in a 12-coordinate geometry to three equivalent W3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2MoW2(SeS)2 by Materials Project

WTe2WSe2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction; one WSe2 sheet oriented in the (0, 0, 1) direction; and one WTe2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo6+ is bonded to six S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. All Mo–S bond lengths are 2.46 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the second S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent Mo6+ atoms. In the WSe2 sheet, W3+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing WSe6 pentagonal pyramids. All W–Se bond lengths are 2.56 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent W3+ atoms. In the WTe2 sheet, W3+ is bonded to six Te2- atoms to form distorted edge-sharing WTe6 pentagonal pyramids. There are three shorter (2.71 Å) and three longer (2.72 Å) W–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent W3+ atoms. In the second Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent W3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2Mo2W(SeS)2 by Materials Project

MoTe2MoSe2WS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoSe2 sheet oriented in the (0, 0, 1) direction; one MoTe2 sheet oriented in the (0, 0, 1) direction; and one WS2 sheet oriented in the (0, 0, 1) direction. In the MoSe2 sheet, Mo+4.50+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.55 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.50+ atoms. In the MoTe2 sheet, Mo+4.50+ is bonded to six Te2- atoms to form distorted edge-sharing MoTe6 pentagonal pyramids. There are three shorter (2.70 Å) and three longer (2.71 Å) Mo–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.50+ atoms. In the second Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent Mo+4.50+ atoms. In the WS2 sheet, W3+ is bonded to six S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.46 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent W3+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent W3+ atoms.

36 MATERIALS SCIENCE↗