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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on SbXe2OF15 by Materials Project

XeF5XeOF4SbF6 crystallizes in the monoclinic P2_1/m space group. The structure is zero-dimensional and consists of two SbF6 clusters, two XeF5 clusters, and two XeOF4 clusters. In each SbF6 cluster, Sb is bonded in an octahedral geometry to six F atoms. There are a spread of Sb–F bond distances ranging from 1.89–1.97 Å. There are five inequivalent F sites. In the first F site, F is bonded in a distorted single-bond geometry to one Sb atom. In the second F site, F is bonded in a single-bond geometry to one Sb atom. In the third F site, F is bonded in a single-bond geometry to one Sb atom. In the fourth F site, F is bonded in a single-bond geometry to one Sb atom. In the fifth F site, F is bonded in a single-bond geometry to one Sb atom. In each XeF5 cluster, Xe is bonded in a 5-coordinate geometry to five F atoms. There are a spread of Xe–F bond distances ranging from 1.95–1.98 Å. There are three inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom. In the third F site, F is bonded in a single-bond geometry to one Xe atom. In each XeOF4 cluster, Xe is bonded in a square pyramidal geometry to one O and four F atoms. The Xe–O bond length is 1.83 Å. All Xe–F bond lengths are 2.03 Å. O is bonded in a single-bond geometry to one Xe atom. There are two inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pt4(O3F8)3 by Materials Project

(PtF6)2PtOF6PtO3F5(O2)2OF crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one hypofluorous acid molecule, two oxygen molecules, two PtF6 clusters, one PtO3F5 cluster, and one PtOF6 cluster. In each PtF6 cluster, Pt is bonded in an octahedral geometry to six F atoms. There are a spread of Pt–F bond distances ranging from 1.90–1.93 Å. There are six inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Pt atom. In the second F site, F is bonded in a single-bond geometry to one Pt atom. In the third F site, F is bonded in a single-bond geometry to one Pt atom. In the fourth F site, F is bonded in a single-bond geometry to one Pt atom. In the fifth F site, F is bonded in a single-bond geometry to one Pt atom. In the sixth F site, F is bonded in a single-bond geometry to one Pt atom. In the PtO3F5 cluster, Pt is bonded in an octahedral geometry to one O and five F atoms. The Pt–O bond length is 2.16 Å. There are a spread of Pt–F bond distances ranging from 1.91–2.17 Å. There are three inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one Pt and one O atom. The O–O bond length is 1.24 Å. In the second O site, O is bonded in a single-bond geometry to one F atom. The O–F bond length is 1.42 Å. In the third O site, O is bonded in a single-bond geometry to one O atom. There are five inequivalent F sites. In the first F site, F is bonded in a bent 120 degrees geometry to one Pt and one O atom. In the second F site, F is bonded in a single-bond geometry to one Pt atom. In the third F site, F is bonded in a single-bond geometry to one Pt atom. In the fourth F site, F is bonded in a single-bond geometry to one Pt atom. In the fifth F site, F is bonded in a single-bond geometry to one Pt atom. In the PtOF6 cluster, Pt is bonded in an octahedral geometry to six F atoms. There are a spread of Pt–F bond distances ranging from 1.91–2.25 Å. O is bonded in a single-bond geometry to one F atom. The O–F bond length is 1.40 Å. There are six inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Pt atom. In the second F site, F is bonded in a single-bond geometry to one Pt atom. In the third F site, F is bonded in a bent 120 degrees geometry to one Pt and one O atom. In the fourth F site, F is bonded in a single-bond geometry to one Pt atom. In the fifth F site, F is bonded in a single-bond geometry to one Pt atom. In the sixth F site, F is bonded in a single-bond geometry to one Pt atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KH28S4N7O16 by Materials Project

(KNH5O4)2(H2)6(NHO)2(HNO2)2(H2S)2(NH4SO)2(N2H3SO)2(NO)2(H2O)4H2O2(SO3H)2 crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one aminohydroperoxide molecule, three hydrogen molecules, one hydrogen sulfide molecule, one hydroxylamine molecule, one hydroxylamine molecule, two water molecules, one water molecule, one KNH5O4 cluster, one N2H3SO cluster, one NH4SO cluster, and one SO3H cluster. In the KNH5O4 cluster, K1+ is bonded in a 2-coordinate geometry to one H1+ and one O2- atom. The K–H bond length is 2.41 Å. The K–O bond length is 2.64 Å. N+1.57+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.20 Å) and one longer (2.12 Å) N–O bond length. There are five inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one H1+ atom. The H–H bond length is 0.75 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.01 Å) and one longer (1.64 Å) H–O bond length. In the fifth H1+ site, H1+ is bonded in a distorted L-shaped geometry to one K1+ and one H1+ atom. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a water-like geometry to one K1+ and two H1+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one N+1.57+, one H1+, and one O2- atom. The O–O bond length is 1.44 Å. In the third O2- site, O2- is bonded in a single-bond geometry to one N+1.57+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one H1+ and one O2- atom. In the N2H3SO cluster, there are two inequivalent N+1.57+ sites. In the first N+1.57+ site, N+1.57+ is bonded in a single-bond geometry to one S2- atom. The N–S bond length is 1.48 Å. In the second N+1.57+ site, N+1.57+ is bonded in a bent 120 degrees geometry to one H1+ and one S2- atom. The N–H bond length is 1.03 Å. The N–S bond length is 1.55 Å. There are three inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one S2- atom. The H–S bond length is 1.42 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N+1.57+ atom. S2- is bonded in a tetrahedral geometry to two N+1.57+, one H1+, and one O2- atom. The S–O bond length is 1.74 Å. O2- is bonded in a distorted water-like geometry to one H1+ and one S2- atom. In the NH4SO cluster, N+1.57+ is bonded in a distorted trigonal non-coplanar geometry to two H1+ and one S2- atom. Both N–H bond lengths are 1.03 Å. The N–S bond length is 1.66 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N+1.57+ atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one S2- atom. The H–S bond length is 1.35 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N+1.57+ atom. S2- is bonded in a 3-coordinate geometry to one N+1.57+, one H1+, and one O2- atom. The S–O bond length is 1.65 Å. O2- is bonded in a distorted water-like geometry to one H1+ and one S2- atom. In the SO3H cluster, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. S2- is bonded in a water-like geometry to two O2- atoms. There is one shorter (1.51 Å) and one longer (1.75 Å) S–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one S2- and one O2- atom. The O–O bond length is 1.44 Å. In the second O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the third O2- site, O2- is bonded in a single-bond geometry to one H1+ and one O2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on As2Kr3F16 by Materials Project

Kr2F3KrAsF7AsF6 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four AsF6 clusters, four Kr2F3 clusters, and four KrAsF7 clusters. In each AsF6 cluster, As is bonded in an octahedral geometry to six F atoms. There is three shorter (1.77 Å) and three longer (1.78 Å) As–F bond length. There are six inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one As atom. In the second F site, F is bonded in a single-bond geometry to one As atom. In the third F site, F is bonded in a single-bond geometry to one As atom. In the fourth F site, F is bonded in a single-bond geometry to one As atom. In the fifth F site, F is bonded in a single-bond geometry to one As atom. In the sixth F site, F is bonded in a single-bond geometry to one As atom. In each Kr2F3 cluster, there are two inequivalent Kr sites. In the first Kr site, Kr is bonded in a linear geometry to two F atoms. There is one shorter (1.85 Å) and one longer (2.09 Å) Kr–F bond length. In the second Kr site, Kr is bonded in a linear geometry to two F atoms. There is one shorter (1.85 Å) and one longer (2.09 Å) Kr–F bond length. There are three inequivalent F sites. In the first F site, F is bonded in a bent 120 degrees geometry to two Kr atoms. In the second F site, F is bonded in a single-bond geometry to one Kr atom. In the third F site, F is bonded in a single-bond geometry to one Kr atom. In each KrAsF7 cluster, Kr is bonded in a linear geometry to two F atoms. There is one shorter (1.85 Å) and one longer (2.09 Å) Kr–F bond length. As is bonded in an octahedral geometry to six F atoms. There are a spread of As–F bond distances ranging from 1.74–2.01 Å. There are seven inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Kr atom. In the second F site, F is bonded in a bent 120 degrees geometry to one Kr and one As atom. In the third F site, F is bonded in a single-bond geometry to one As atom. In the fourth F site, F is bonded in a single-bond geometry to one As atom. In the fifth F site, F is bonded in a single-bond geometry to one As atom. In the sixth F site, F is bonded in a single-bond geometry to one As atom. In the seventh F site, F is bonded in a single-bond geometry to one As atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Ab Initio Molecular Dynamics Study of Pd Nucleation on a γ-Al 2 O 3 Surface

We perform ab initio molecular dynamics (AIMD) free energy simulations to investigate the stability and dynamics of dispersed Pd atoms and subnanometer clusters on γ-Al 2 O 3 . We consider nucleation for varying Pd loadings on dry γ-Al 2 O 3 (100), dry γ-Al 2 O 3 (110) and wet γ-Al 2 O 3 (110) and examine temperature, entropy and water coverage effects on the stability and dynamics of Pd clusters. At low Pd loading (1.07 Pd atoms/nm 2 on the (100) and 0.75 Pd/nm 2 on the (110)), association of the Pd atoms is thermodynamically unfavorable on the dry surfaces and almost thermoneutral on the wet (110) owing to water blocking of the AlIII defect sites. In agreement with past studies, the Pd atoms are quite mobile but the diffusion free energy barriers do not increase with the water coverage, as previously suggested, but rather remain similar in magnitude owing to translational entropy at finite temperatures. At these Pd loadings, oxidized Pd(II) atoms on the wet (110) surface are dispersed and immobile. At higher Pd loading (1.12 and 1.5 Pd atoms/nm 2 ) on the (110) surface, Pd 3 and Pd 4 clusters are thermodynamically very stable and form fast. At the 1.12 Pd atoms/nm 2 loading, the formation of the Pd 3 cluster is two orders of magnitude slower when the surface is hydroxylated as the system becomes somewhat trapped before the dinuclear cluster Pd 2 collides with a Pd atom.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1992

Equilibrium properties of transition-metal ion-argon clusters via simulated annealing

The geometrical structures of M(+) (Ar)n ions, with n = 1-14, have been studied by the minimization of a many-body potential surface with a simulated annealing procedure. The minimization method is justified for finite systems through the use of an information theory approach. It is carried out for eight potential-energy surfaces constructed with two- and three-body terms parametrized from experimental data and ab initio results. The potentials should be representative of clusters of argon atoms with first-row transition-metal monocations of varying size. The calculated geometries for M(+) = Co(+) and V(+) possess radial shells with small (ca. 4-8) first-shell coordination number. The inclusion of an ion-induced-dipole-ion-induced-dipole interaction between argon atoms raises the energy and generally lowers the symmetry of the cluster by promoting incomplete shell closure. Rotational constants as well as electric dipole and quadrupole moments are quoted for the Co(+) (Ar)n and V(+) (Ar)n predicted structures.

Asher, Robert L.↗
DOE OSTI2020

Atomic Layer Deposition for Preparing Isolated Co Sites on SiO 2 for Ethane Dehydrogenation Catalysis

Unlike Co clusters, isolated Co atoms have been shown to be selective for catalytic dehydrogenation of ethane to ethylene; however, preparation of isolated Co sites requires special preparation procedures. Here, we demonstrate that Atomic Layer Deposition (ALD) of tris(2,2,6,6-tetramethyl-3,5-heptanedionato)cobalt(III) (Co(TMHD) 3 ) on silica and other supports is effective in producing these isolated species. Silica-supported catalysts prepared with one ALD cycle showed ethylene selectivities greater than 96% at 923 K and were stable when CO 2 was co-fed with the ethane. Co catalysts prepared by impregnation formed clusters that were significantly less active, selective, and stable. Rates and selectivities also decreased for catalysts with multiple ALD cycles. Isolated Co catalysts prepared on Al 2 O 3 and MgAl 2 O 4 showed reasonable selectivity for ethane dehydrogenation but were not as effective as their silica counterpart.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AgAsS16N16(O4F3)2 by Materials Project

AgS12(N2O)6(N2S2O)2AsF6 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two AgS12(N2O)6 clusters, two AsF6 clusters, and two N2S2O clusters. In each AgS12(N2O)6 cluster, Ag1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of Ag–O bond distances ranging from 2.83–3.24 Å. There are twelve inequivalent N3+ sites. In the first N3+ site, N3+ is bonded in a bent 120 degrees geometry to two S2- atoms. There is one shorter (1.60 Å) and one longer (1.64 Å) N–S bond length. In the second N3+ site, N3+ is bonded in a bent 150 degrees geometry to two S2- atoms. There is one shorter (1.55 Å) and one longer (1.58 Å) N–S bond length. In the third N3+ site, N3+ is bonded in a bent 150 degrees geometry to two S2- atoms. There is one shorter (1.56 Å) and one longer (1.60 Å) N–S bond length. In the fourth N3+ site, N3+ is bonded in a bent 120 degrees geometry to two S2- atoms. There is one shorter (1.58 Å) and one longer (1.64 Å) N–S bond length. In the fifth N3+ site, N3+ is bonded in a bent 120 degrees geometry to two S2- atoms. There is one shorter (1.59 Å) and one longer (1.65 Å) N–S bond length. In the sixth N3+ site, N3+ is bonded in a bent 150 degrees geometry to two S2- atoms. There is one shorter (1.56 Å) and one longer (1.59 Å) N–S bond length. In the seventh N3+ site, N3+ is bonded in a bent 150 degrees geometry to two S2- atoms. There is one shorter (1.57 Å) and one longer (1.59 Å) N–S bond length. In the eighth N3+ site, N3+ is bonded in a bent 120 degrees geometry to two S2- atoms. There is one shorter (1.57 Å) and one longer (1.63 Å) N–S bond length. In the ninth N3+ site, N3+ is bonded in a bent 120 degrees geometry to two S2- atoms. There is one shorter (1.59 Å) and one longer (1.65 Å) N–S bond length. In the tenth N3+ site, N3+ is bonded in a bent 150 degrees geometry to two S2- atoms. There is one shorter (1.56 Å) and one longer (1.59 Å) N–S bond length. In the eleventh N3+ site, N3+ is bonded in a bent 150 degrees geometry to two S2- atoms. There is one shorter (1.57 Å) and one longer (1.59 Å) N–S bond length. In the twelfth N3+ site, N3+ is bonded in a bent 120 degrees geometry to two S2- atoms. There is one shorter (1.57 Å) and one longer (1.63 Å) N–S bond length. There are twelve inequivalent S2- sites. In the first S2- site, S2- is bonded in a bent 120 degrees geometry to two N3+ atoms. In the second S2- site, S2- is bonded in a bent 120 degrees geometry to two N3+ atoms. In the third S2- site, S2- is bonded in a distorted bent 120 degrees geometry to two N3+ atoms. In the fourth S2- site, S2- is bonded in a bent 120 degrees geometry to two N3+ atoms. In the fifth S2- site, S2- is bonded in a bent 120 degrees geometry to two N3+ atoms. In the sixth S2- site, S2- is bonded in a bent 120 degrees geometry to two N3+ atoms. In the seventh S2- site, S2- is bonded in a tetrahedral geometry to two N3+ and two O2- atoms. There is one shorter (1.44 Å) and one longer (1.45 Å) S–O bond length. In the eighth S2- site, S2- is bonded in a bent 120 degrees geometry to two N3+ atoms. In the ninth S2- site, S2- is bonded in a bent 120 degrees geometry to two N3+ atoms. In the tenth S2- site, S2- is bonded in a tetrahedral geometry to two N3+ and two O2- atoms. Both S–O bond lengths are 1.45 Å. In the eleventh S2- site, S2- is bonded in a tetrahedral geometry to two N3+ and two O2- atoms. There is one shorter (1.44 Å) and one longer (1.45 Å) S–O bond length. In the twelfth S2- site, S2- is bonded in a distorted bent 120 degrees geometry to two N3+ atoms. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Ag1+ and one S2- atom. In the second O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the third O2- site, O2- is bonded in a single-bond geometry to one Ag1+ and one S2- atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to one Ag1+ and one S2- atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In each AsF6 cluster, As5+ is bonded in an octahedral geometry to six F1- atoms. There is one shorter (1.77 Å) and five longer (1.78 Å) As–F bond length. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the sixth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In each N2S2O cluster, there are four inequivalent N3+ sites. In the first N3+ site, N3+ is bonded in a bent 150 degrees geometry to two S2- atoms. There is one shorter (1.56 Å) and one longer (1.59 Å) N–S bond length. In the second N3+ site, N3+ is bonded in a bent 120 degrees geometry to two S2- atoms. There is one shorter (1.57 Å) and one longer (1.63 Å) N–S bond length. In the third N3+ site, N3+ is bonded in a bent 120 degrees geometry to two S2- atoms. There is one shorter (1.59 Å) and one longer (1.65 Å) N–S bond length. In the fourth N3+ site, N3+ is bonded in a bent 150 degrees geometry to two S2- atoms. There is one shorter (1.56 Å) and one longer (1.60 Å) N–S bond length. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a tetrahedral geometry to two N3+ and two O2- atoms. There is one shorter (1.44 Å) and one longer (1.45 Å) S–O bond length. In the second S2- site, S2- is bonded in a bent 120 degrees geometry to two N3+ atoms. In the third S2- site, S2- is bonded in a bent 120 degrees geometry to two N3+ atoms. In the fourth S2- site, S2- is bonded in a bent 120 degrees geometry to two N3+ atoms. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the second O2- site, O2- is bonded in a single-bond geometry to one S2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Energetics and Structure of Ag–Water Clusters Formed in Mordenite

Zeolite-supported Ag 0 clusters have broad applications from catalysis to medicine, necessitating a mechanistic understanding of the formation of Ag 0 clusters in situ. Density functional theory (DFT) simulations have been performed on silver, water, and silver–water clusters in silica mordenite (Si-MOR), to identify the role of the confinement on the structure and energetics of Ag 0 cluster formation. The most favorable binding energy in the 12-membered ring (MR) pore of the Si-MOR is a 10–15-atom Ag 0 cluster. Computational pair distribution function (PDF) data indicates that the Ag 0 and Ag 0 –H 2 O clusters formed in vacuum versus in Si-MOR exhibit structural differences. Additionally, when the Ag 0 cluster is confined, the density decreases and the surface area increases, hypothesized to be due to the limiting geometry of the 12-MR main channel. An energetic drive toward formation of larger Ag 0 clusters was also identified, with hydrated silver atoms generating higher energy structures. In conclusion, this work identifies mechanistic and structural insight into the role of nanoconfinement on formation of Ag 0 clusters in mordenite.

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

Materials Data on InTe14(IrBr8)2 by Materials Project

(Ir)2InBr4(Te)7(Te2Br3)2(TeBr2)3 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of four iridium molecules, fourteen tellurium molecules, two InBr4 clusters, two Te2Br3 clusters, and two TeBr2 clusters. In each InBr4 cluster, In3+ is bonded in a tetrahedral geometry to four Br1- atoms. There are a spread of In–Br bond distances ranging from 2.54–2.57 Å. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one In3+ atom. In the second Br1- site, Br1- is bonded in a single-bond geometry to one In3+ atom. In the third Br1- site, Br1- is bonded in a single-bond geometry to one In3+ atom. In the fourth Br1- site, Br1- is bonded in a single-bond geometry to one In3+ atom. In each Te2Br3 cluster, there are four inequivalent Te+0.29+ sites. In the first Te+0.29+ site, Te+0.29+ is bonded in a 1-coordinate geometry to one Br1- atom. The Te–Br bond length is 3.39 Å. In the second Te+0.29+ site, Te+0.29+ is bonded in a distorted single-bond geometry to one Br1- atom. The Te–Br bond length is 3.45 Å. In the third Te+0.29+ site, Te+0.29+ is bonded in a rectangular see-saw-like geometry to four Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.64–2.98 Å. In the fourth Te+0.29+ site, Te+0.29+ is bonded in a rectangular see-saw-like geometry to four Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.64–2.98 Å. There are six inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Te+0.29+ atom. In the second Br1- site, Br1- is bonded in a 2-coordinate geometry to three Te+0.29+ atoms. In the third Br1- site, Br1- is bonded in a single-bond geometry to one Te+0.29+ atom. In the fourth Br1- site, Br1- is bonded in a 2-coordinate geometry to three Te+0.29+ atoms. In the fifth Br1- site, Br1- is bonded in a single-bond geometry to one Te+0.29+ atom. In the sixth Br1- site, Br1- is bonded in a single-bond geometry to one Te+0.29+ atom. In each TeBr2 cluster, there are three inequivalent Te+0.29+ sites. In the first Te+0.29+ site, Te+0.29+ is bonded in a single-bond geometry to one Br1- atom. The Te–Br bond length is 3.33 Å. In the second Te+0.29+ site, Te+0.29+ is bonded in a rectangular see-saw-like geometry to four Br1- atoms. There are two shorter (2.67 Å) and two longer (2.94 Å) Te–Br bond lengths. In the third Te+0.29+ site, Te+0.29+ is bonded in a rectangular see-saw-like geometry to four Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.64–3.03 Å. There are six inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Te+0.29+ atom. In the second Br1- site, Br1- is bonded in a 2-coordinate geometry to two Te+0.29+ atoms. In the third Br1- site, Br1- is bonded in a 3-coordinate geometry to three Te+0.29+ atoms. In the fourth Br1- site, Br1- is bonded in a single-bond geometry to one Te+0.29+ atom. In the fifth Br1- site, Br1- is bonded in a single-bond geometry to one Te+0.29+ atom. In the sixth Br1- site, Br1- is bonded in a single-bond geometry to one Te+0.29+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS2023

4.46 Ga Zircons Anchor Chronology of Lunar Magma Ocean

The crystallisation ages of lunar samples provide critical constraints on the minimum formation age of the Moon and its early evolution. Zircon crystals from Apollo 17 lunar impact melt breccia 72255 preserve ancient domains with a concordant average uranium-lead radiometric date of 4460 ± 31 Ma (Zhang et al., 2021), the oldest lunar zircon yet reported. To assess the possible mobility of radiogenic lead in zircon, which may lead to redistribution and clustering of Pb atoms that may cause a U-Pb age bias (Valley et al., 2014), we investigated a zircon grain from Zhang et al. (2021) by atom probe tomography (APT). The atomic spatial resolution analysis of individual mineral grains demonstrates the absence of nanoscale clustering of lead, which supports a 4.46 Ga ancient formation age for lunar zircon in sample 72255. This age pushes back the age of the first preserved lunar crust by ∼40 Myr and provides a minimum formation age for the Moon within 110 Myr after the formation of the solar system.

atom probe tomography↗
NASA NTRS1977

On the character of the melting transition in small atomic aggregates

A biased random walk, Monte Carlo procedure is used to study the melting transition in small clusters of N atoms. Results show an abrupt change in physical properties near melting, but there is no evidence that the transition is either first or second order; rather the transition is more gradual.

Etters, R. D.↗
DOE OSTI2020

Materials Data on Sb2XeF15 by Materials Project

XeF4Sb2F11 crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four Sb2F11 clusters and four XeF4 clusters. In each Sb2F11 cluster, Sb is bonded to six F atoms to form corner-sharing SbF6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Sb–F bond distances ranging from 1.89–2.08 Å. There are six inequivalent F sites. In the first F site, F is bonded in a linear geometry to two equivalent Sb atoms. In the second F site, F is bonded in a single-bond geometry to one Sb atom. In the third F site, F is bonded in a single-bond geometry to one Sb atom. In the fourth F site, F is bonded in a single-bond geometry to one Sb atom. In the fifth F site, F is bonded in a single-bond geometry to one Sb atom. In the sixth F site, F is bonded in a single-bond geometry to one Sb atom. In each XeF4 cluster, Xe is bonded in a square co-planar geometry to four F atoms. There are two shorter (2.00 Å) and two longer (2.02 Å) Xe–F bond lengths. There are two inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AgS8N9(ClO6)2 by Materials Project

(NAgN)2N2(NS2)4(N2Cl)4(SO3)8 crystallizes in the tetragonal I-42d space group. The structure is zero-dimensional and consists of four ammonia molecules, sixteen sulfur trioxide molecules, eight N2Cl clusters, four NAgN clusters, and eight NS2 clusters. In each N2Cl cluster, N+4.56+ is bonded in a single-bond geometry to one Cl1- atom. The N–Cl bond length is 1.50 Å. Cl1- is bonded in a distorted bent 150 degrees geometry to two equivalent N+4.56+ atoms. In each NAgN cluster, Ag1+ is bonded in a distorted linear geometry to two equivalent N+4.56+ atoms. Both Ag–N bond lengths are 2.07 Å. N+4.56+ is bonded in a single-bond geometry to one Ag1+ atom. In each NS2 cluster, N+4.56+ is bonded in a linear geometry to two equivalent S2- atoms. Both N–S bond lengths are 1.53 Å. S2- is bonded in a distorted single-bond geometry to one N+4.56+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

In Situ Dispersion of Palladium on TiO 2 During Reverse Water–Gas Shift Reaction: Formation of Atomically Dispersed Palladium

The application of single-atom catalysts (SACs) to high-temperature hydrogenation requires materials that thermodynamically favor metal atom isolation over cluster formation. Here, we show that Pd can be predominantly dispersed as isolated atoms onto TiO 2 during the reverse water-gas shift (rWGS) reaction at 400 °C. Achieving atomic dispersion requires an artificial increase of the absolute TiO 2 surface area by an order of magnitude and can be accomplished by physically mixing a precatalyst (Pd/TiO 2 ) with neat TiO 2 prior to the rWGS reaction. Furthermore, the in situ dispersion of Pd was reflected through a continuous increase of rWGS activity over 92 h and supported by kinetic analysis, infrared and X-ray absorption spectroscopies and scanning transmission electron microscopy. The thermodynamic stability of Pd under high-temperature rWGS conditions is associated with Pd-Ti coordination, which manifests upon O-vacancy formation and the artificial increase in TiO 2 surface area.

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

Materials Data on TeP3(N2O9)2 by Materials Project

PNO5PNO4PN2TeO9 crystallizes in the monoclinic Pc space group. The structure is zero-dimensional and consists of two PN2TeO9 clusters, two PNO4 clusters, and two PNO5 clusters. In each PN2TeO9 cluster, P+4.67+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.48 Å) and one longer (1.63 Å) P–O bond length. There are two inequivalent N+4.50+ sites. In the first N+4.50+ site, N+4.50+ is bonded in a distorted bent 120 degrees geometry to two O2- atoms. There is one shorter (1.12 Å) and one longer (1.94 Å) N–O bond length. In the second N+4.50+ site, N+4.50+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.22 Å) and one longer (1.28 Å) N–O bond length. Te4+ is bonded in a distorted trigonal bipyramidal geometry to five O2- atoms. There are a spread of Te–O bond distances ranging from 1.80–2.37 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one P+4.67+ and one Te4+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one P+4.67+ atom. In the third O2- site, O2- is bonded in a distorted water-like geometry to one N+4.50+ and one Te4+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one N+4.50+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to one Te4+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one P+4.67+ atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one N+4.50+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one Te4+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one N+4.50+ and one Te4+ atom. In each PNO4 cluster, P+4.67+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.48 Å) and one longer (1.55 Å) P–O bond length. N+4.50+ is bonded in a water-like geometry to two O2- atoms. There is one shorter (1.13 Å) and one longer (1.85 Å) N–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one P+4.67+ and one N+4.50+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one N+4.50+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one P+4.67+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one P+4.67+ atom. In each PNO5 cluster, P+4.67+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.53–1.56 Å. N+4.50+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.13 Å) and one longer (1.92 Å) N–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one P+4.67+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one N+4.50+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one P+4.67+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one P+4.67+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one P+4.67+ and one N+4.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NbP4(S2Cl)5 by Materials Project

NbCl5(P2S5)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of one NbCl5 cluster and two P2S5 clusters. In the NbCl5 cluster, Nb5+ is bonded to six Cl1- atoms to form edge-sharing NbCl6 octahedra. There are a spread of Nb–Cl bond distances ranging from 2.28–2.60 Å. There are four inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Nb5+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Nb5+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Nb5+ atom. In the fourth Cl1- site, Cl1- is bonded in a water-like geometry to two equivalent Nb5+ atoms. In each P2S5 cluster, there are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four S2- atoms to form corner-sharing PS4 tetrahedra. There are one shorter (1.92 Å) and three longer (2.12 Å) P–S bond lengths. In the second P5+ site, P5+ is bonded to four S2- atoms to form corner-sharing PS4 tetrahedra. There are one shorter (1.92 Å) and three longer (2.12 Å) P–S bond lengths. In the third P5+ site, P5+ is bonded to four S2- atoms to form corner-sharing PS4 tetrahedra. There are one shorter (1.92 Å) and three longer (2.12 Å) P–S bond lengths. In the fourth P5+ site, P5+ is bonded to four S2- atoms to form corner-sharing PS4 tetrahedra. There are one shorter (1.92 Å) and three longer (2.12 Å) P–S bond lengths. There are ten inequivalent S2- sites. In the first S2- site, S2- is bonded in a single-bond geometry to one P5+ atom. In the second S2- site, S2- is bonded in a water-like geometry to two P5+ atoms. In the third S2- site, S2- is bonded in a water-like geometry to two P5+ atoms. In the fourth S2- site, S2- is bonded in a water-like geometry to two P5+ atoms. In the fifth S2- site, S2- is bonded in a single-bond geometry to one P5+ atom. In the sixth S2- site, S2- is bonded in a water-like geometry to two P5+ atoms. In the seventh S2- site, S2- is bonded in a single-bond geometry to one P5+ atom. In the eighth S2- site, S2- is bonded in a water-like geometry to two P5+ atoms. In the ninth S2- site, S2- is bonded in a single-bond geometry to one P5+ atom. In the tenth S2- site, S2- is bonded in a water-like geometry to two P5+ atoms.

36 MATERIALS SCIENCE↗