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At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Metal-Silicate-Sulfide Partitioning of U, Th, and K: Implications for the Budget of Volatile Elements in Mercury

During formation of the solar system, the Sun produced strong solar winds, which stripped away a portion of the volatile elements from the forming planets. Hence, it was expected that planets closest to the sun, such as Mercury, are more depleted in volatile elements in comparison to other terrestrial planets. However, the MESSENGER mission detected higher than expected K/U and K/Th ratios on Mercury's surface, indicating a volatile content between that of Mars and Earth. Our experiments aim to resolve this discrepancy by experimentally determining the partition coefficients (D(sup met/sil)) of K, U, and Th between metal and silicate at varying pressure (1 to 5 GPa), temperature (1500 to 1900 C), oxygen fugacity (IW-2.5 to IW-6.5) and sulfur-content in the metal (0 to 33 wt%). Our data show that U, Th, and K become more siderophile with decreasing fO2 and increasing sulfur-content, with a stronger effect for U and Th in comparison to K. Using these results, the concentrations of U, Th, and K in the bulk planet were calculated for different scenarios, where the planet equilibrated at a fO2 between IW-4 and IW-7, assuming the existence of a FeS layer, between the core and mantle, with variable thickness. These models show that significant amounts of U and Th are partitioned into Mercury's core. The elevated superficial K/U and K/Th values are therefore only a consequence of the sequestration of U and Th into the core, not evidence of the overall volatile content of Mercury.

Habermann, M.↗
DOE OSTI2020

Materials Data on U(SiIr)2 by Materials Project

UIr2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Ir and eight equivalent Si atoms. All U–Ir bond lengths are 3.22 Å. All U–Si bond lengths are 3.07 Å. Ir is bonded to four equivalent U and four equivalent Si atoms to form a mixture of distorted edge, face, and corner-sharing IrU4Si4 tetrahedra. All Ir–Si bond lengths are 2.43 Å. Si is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Ir, and one Si atom. The Si–Si bond length is 2.30 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(MnGe)2 by Materials Project

UMn2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Mn and eight equivalent Ge atoms. All U–Mn bond lengths are 3.29 Å. All U–Ge bond lengths are 3.09 Å. Mn is bonded to four equivalent U and four equivalent Ge atoms to form a mixture of face, edge, and corner-sharing MnU4Ge4 tetrahedra. All Mn–Ge bond lengths are 2.41 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Mn, and one Ge atom. The Ge–Ge bond length is 2.51 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(FeGe)2 by Materials Project

UFe2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Fe and eight equivalent Ge atoms. All U–Fe bond lengths are 3.12 Å. All U–Ge bond lengths are 3.11 Å. Fe is bonded in a 4-coordinate geometry to four equivalent U and four equivalent Ge atoms. All Fe–Ge bond lengths are 2.32 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Fe, and one Ge atom. The Ge–Ge bond length is 2.48 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(CoGe)2 by Materials Project

UCo2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Co and eight equivalent Ge atoms. All U–Co bond lengths are 3.13 Å. All U–Ge bond lengths are 3.11 Å. Co is bonded in a 4-coordinate geometry to four equivalent U and four equivalent Ge atoms. All Co–Ge bond lengths are 2.33 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Co, and one Ge atom. The Ge–Ge bond length is 2.46 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(GeIr)2 by Materials Project

UIr2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Ir and eight equivalent Ge atoms. All U–Ir bond lengths are 3.33 Å. All U–Ge bond lengths are 3.17 Å. Ir is bonded to four equivalent U and four equivalent Ge atoms to form a mixture of distorted face, edge, and corner-sharing IrU4Ge4 tetrahedra. All Ir–Ge bond lengths are 2.48 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Ir, and one Ge atom. The Ge–Ge bond length is 2.48 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(GeRh)2 by Materials Project

URh2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Rh and eight equivalent Ge atoms. All U–Rh bond lengths are 3.34 Å. All U–Ge bond lengths are 3.16 Å. Rh is bonded to four equivalent U and four equivalent Ge atoms to form a mixture of distorted face, edge, and corner-sharing RhU4Ge4 tetrahedra. All Rh–Ge bond lengths are 2.47 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Rh, and one Ge atom. The Ge–Ge bond length is 2.50 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(CuGe)2 by Materials Project

UCu2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Cu and eight equivalent Ge atoms. All U–Cu bond lengths are 3.28 Å. All U–Ge bond lengths are 3.11 Å. Cu is bonded to four equivalent U and four equivalent Ge atoms to form a mixture of distorted face, edge, and corner-sharing CuU4Ge4 tetrahedra. All Cu–Ge bond lengths are 2.43 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Cu, and one Ge atom. The Ge–Ge bond length is 2.46 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(GePd)2 by Materials Project

UPd2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Pd and eight equivalent Ge atoms. All U–Pd bond lengths are 3.37 Å. All U–Ge bond lengths are 3.19 Å. Pd is bonded to four equivalent U and four equivalent Ge atoms to form a mixture of distorted face, edge, and corner-sharing PdU4Ge4 tetrahedra. All Pd–Ge bond lengths are 2.53 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Pd, and one Ge atom. The Ge–Ge bond length is 2.43 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(SiRh)2 by Materials Project

URh2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Rh and eight equivalent Si atoms. All U–Rh bond lengths are 3.21 Å. All U–Si bond lengths are 3.06 Å. Rh is bonded to four equivalent U and four equivalent Si atoms to form a mixture of distorted corner, edge, and face-sharing RhU4Si4 tetrahedra. All Rh–Si bond lengths are 2.42 Å. Si is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Rh, and one Si atom. The Si–Si bond length is 2.31 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(NiGe)2 by Materials Project

UNi2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Ni and eight equivalent Ge atoms. All U–Ni bond lengths are 3.18 Å. All U–Ge bond lengths are 3.12 Å. Ni is bonded in a 4-coordinate geometry to four equivalent U and four equivalent Ge atoms. All Ni–Ge bond lengths are 2.36 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Ni, and one Ge atom. The Ge–Ge bond length is 2.47 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(MoO4)2 by Materials Project

UMo2O8 crystallizes in the trigonal P3 space group. The structure is three-dimensional. there are five inequivalent U4+ sites. In the first U4+ site, U4+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of U–O bond distances ranging from 2.31–2.50 Å. In the second U4+ site, U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six MoO4 tetrahedra. There are three shorter (2.20 Å) and three longer (2.21 Å) U–O bond lengths. In the third U4+ site, U4+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of U–O bond distances ranging from 2.34–2.45 Å. In the fourth U4+ site, U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six MoO4 tetrahedra. All U–O bond lengths are 2.20 Å. In the fifth U4+ site, U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six MoO4 tetrahedra. All U–O bond lengths are 2.19 Å. There are six inequivalent Mo6+ sites. In the first Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 30°. There are a spread of Mo–O bond distances ranging from 1.77–1.85 Å. In the second Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 26°. There are a spread of Mo–O bond distances ranging from 1.77–1.86 Å. In the third Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 21°. There are a spread of Mo–O bond distances ranging from 1.77–1.87 Å. In the fourth Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 37°. There are a spread of Mo–O bond distances ranging from 1.77–1.85 Å. In the fifth Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 30°. There are a spread of Mo–O bond distances ranging from 1.77–1.85 Å. In the sixth Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 30°. There are a spread of Mo–O bond distances ranging from 1.77–1.85 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one U4+ and one Mo6+ atom. In the third O2- site, O2- is bonded in a distorted linear geometry to one U4+ and one Mo6+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the tenth O2- site, O2- is bonded in a linear geometry to one U4+ and one Mo6+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the fourteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the fifteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the sixteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the seventeenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the eighteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the nineteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twentieth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twenty-first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twenty-second O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twenty-third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twenty-fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Fe2Ge)2 by Materials Project

UFe4Ge2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. U is bonded in a 10-coordinate geometry to four equivalent Fe and six equivalent Ge atoms. All U–Fe bond lengths are 2.95 Å. There are two shorter (2.89 Å) and four longer (2.92 Å) U–Ge bond lengths. Fe is bonded in a 3-coordinate geometry to one U and three equivalent Ge atoms. There are two shorter (2.47 Å) and one longer (2.48 Å) Fe–Ge bond lengths. Ge is bonded in a 9-coordinate geometry to three equivalent U and six equivalent Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Zn10Ru)2 by Materials Project

U(RuZn10)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. U is bonded in a 4-coordinate geometry to sixteen Zn atoms. There are four shorter (3.08 Å) and twelve longer (3.13 Å) U–Zn bond lengths. Ru is bonded to twelve Zn atoms to form RuZn12 cuboctahedra that share corners with six equivalent RuZn12 cuboctahedra, edges with eighteen equivalent ZnUZn10Ru cuboctahedra, and faces with six equivalent ZnUZn10Ru cuboctahedra. There are six shorter (2.52 Å) and six longer (2.77 Å) Ru–Zn bond lengths. There are three inequivalent Zn sites. In the first Zn site, Zn is bonded in a 2-coordinate geometry to two equivalent U and twelve equivalent Zn atoms. All Zn–Zn bond lengths are 3.03 Å. In the second Zn site, Zn is bonded in a distorted linear geometry to two equivalent Ru and six equivalent Zn atoms. There are two shorter (2.68 Å) and four longer (2.81 Å) Zn–Zn bond lengths. In the third Zn site, Zn is bonded to one U, one Ru, and ten Zn atoms to form distorted ZnUZn10Ru cuboctahedra that share corners with fifteen equivalent ZnUZn10Ru cuboctahedra, edges with two equivalent ZnUZn10Ru cuboctahedra, edges with three equivalent RuZn12 cuboctahedra, a faceface with one RuZn12 cuboctahedra, and faces with fifteen equivalent ZnUZn10Ru cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.64–2.89 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Zn10Co)2 by Materials Project

U(CoZn10)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. U is bonded in a 4-coordinate geometry to sixteen Zn atoms. There are four shorter (3.04 Å) and twelve longer (3.10 Å) U–Zn bond lengths. Co is bonded to twelve Zn atoms to form CoZn12 cuboctahedra that share corners with six equivalent CoZn12 cuboctahedra, edges with eighteen equivalent ZnUZn10Co cuboctahedra, and faces with six equivalent ZnUZn10Co cuboctahedra. There are six shorter (2.49 Å) and six longer (2.73 Å) Co–Zn bond lengths. There are three inequivalent Zn sites. In the first Zn site, Zn is bonded in a 2-coordinate geometry to two equivalent U and twelve equivalent Zn atoms. All Zn–Zn bond lengths are 3.00 Å. In the second Zn site, Zn is bonded in a distorted linear geometry to two equivalent Co and ten Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.64–2.77 Å. In the third Zn site, Zn is bonded to one U, one Co, and ten Zn atoms to form distorted ZnUZn10Co cuboctahedra that share corners with fifteen equivalent ZnUZn10Co cuboctahedra, edges with two equivalent ZnUZn10Co cuboctahedra, edges with three equivalent CoZn12 cuboctahedra, a faceface with one CoZn12 cuboctahedra, and faces with fifteen equivalent ZnUZn10Co cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.61–2.84 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Al10Cr)2 by Materials Project

U(CrAl10)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. U is bonded in a 4-coordinate geometry to sixteen Al atoms. There are four shorter (3.11 Å) and twelve longer (3.17 Å) U–Al bond lengths. Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share corners with six equivalent CrAl12 cuboctahedra, edges with eighteen equivalent AlUAl10Cr cuboctahedra, and faces with six equivalent AlUAl10Cr cuboctahedra. There are six shorter (2.54 Å) and six longer (2.78 Å) Cr–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded in a distorted linear geometry to two equivalent U and twelve equivalent Al atoms. All Al–Al bond lengths are 3.07 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to two equivalent Cr and ten Al atoms. There are a spread of Al–Al bond distances ranging from 2.70–2.82 Å. In the third Al site, Al is bonded to one U, one Cr, and ten Al atoms to form distorted AlUAl10Cr cuboctahedra that share corners with fifteen equivalent AlUAl10Cr cuboctahedra, edges with two equivalent AlUAl10Cr cuboctahedra, edges with three equivalent CrAl12 cuboctahedra, a faceface with one CrAl12 cuboctahedra, and faces with fifteen equivalent AlUAl10Cr cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.68–2.90 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Zn10Ir)2 by Materials Project

U(IrZn10)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. U is bonded in a 4-coordinate geometry to sixteen Zn atoms. All U–Zn bond lengths are 3.09 Å. Ir is bonded to twelve Zn atoms to form IrZn12 cuboctahedra that share corners with six equivalent IrZn12 cuboctahedra, edges with eighteen equivalent ZnUZn10Ir cuboctahedra, and faces with six equivalent ZnUZn10Ir cuboctahedra. There are six shorter (2.53 Å) and six longer (2.83 Å) Ir–Zn bond lengths. There are three inequivalent Zn sites. In the first Zn site, Zn is bonded in a 2-coordinate geometry to two equivalent U and twelve equivalent Zn atoms. All Zn–Zn bond lengths are 3.02 Å. In the second Zn site, Zn is bonded in a distorted linear geometry to two equivalent Ir and six equivalent Zn atoms. There are two shorter (2.68 Å) and four longer (2.84 Å) Zn–Zn bond lengths. In the third Zn site, Zn is bonded to one U, one Ir, and ten Zn atoms to form distorted ZnUZn10Ir cuboctahedra that share corners with fifteen equivalent ZnUZn10Ir cuboctahedra, edges with two equivalent ZnUZn10Ir cuboctahedra, edges with three equivalent IrZn12 cuboctahedra, a faceface with one IrZn12 cuboctahedra, and faces with fifteen equivalent ZnUZn10Ir cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.60–2.94 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Zn10Rh)2 by Materials Project

U(RhZn10)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. U is bonded in a 4-coordinate geometry to sixteen Zn atoms. There are four shorter (3.09 Å) and twelve longer (3.11 Å) U–Zn bond lengths. Rh is bonded to twelve Zn atoms to form RhZn12 cuboctahedra that share corners with six equivalent RhZn12 cuboctahedra, edges with eighteen equivalent ZnUZn10Rh cuboctahedra, and faces with six equivalent ZnUZn10Rh cuboctahedra. There are six shorter (2.53 Å) and six longer (2.80 Å) Rh–Zn bond lengths. There are three inequivalent Zn sites. In the first Zn site, Zn is bonded in a 2-coordinate geometry to two equivalent U and twelve equivalent Zn atoms. All Zn–Zn bond lengths are 3.03 Å. In the second Zn site, Zn is bonded in a distorted linear geometry to two equivalent Rh and six equivalent Zn atoms. There are two shorter (2.69 Å) and four longer (2.83 Å) Zn–Zn bond lengths. In the third Zn site, Zn is bonded to one U, one Rh, and ten Zn atoms to form distorted ZnUZn10Rh cuboctahedra that share corners with fifteen equivalent ZnUZn10Rh cuboctahedra, edges with two equivalent ZnUZn10Rh cuboctahedra, edges with three equivalent RhZn12 cuboctahedra, a faceface with one RhZn12 cuboctahedra, and faces with fifteen equivalent ZnUZn10Rh cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.62–2.92 Å.

36 MATERIALS SCIENCE↗