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At least 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on EuMoO5 by Materials Project

EuMoO5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Eu is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Eu–O bond distances ranging from 2.31–2.52 Å. Mo is bonded in a distorted tetrahedral geometry to five O atoms. There are a spread of Mo–O bond distances ranging from 1.77–2.41 Å. There are five inequivalent O sites. In the first O site, O is bonded in a distorted trigonal non-coplanar geometry to two equivalent Eu and one Mo atom. In the second O site, O is bonded in a distorted trigonal planar geometry to two equivalent Eu and one Mo atom. In the third O site, O is bonded in a distorted trigonal planar geometry to two equivalent Eu and one Mo atom. In the fourth O site, O is bonded in a distorted linear geometry to one Eu and one Mo atom. In the fifth O site, O is bonded in a distorted bent 150 degrees geometry to one Eu and one Mo atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrEu by Materials Project

Eu(Sr1) crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Sr is bonded to six equivalent Sr and six equivalent Eu atoms to form SrSr6Eu6 cuboctahedra that share corners with eighteen equivalent SrSr6Eu6 cuboctahedra, edges with six equivalent SrSr6Eu6 cuboctahedra, edges with twelve equivalent EuSr6Eu6 cuboctahedra, faces with eight equivalent SrSr6Eu6 cuboctahedra, and faces with twelve equivalent EuSr6Eu6 cuboctahedra. All Sr–Sr bond lengths are 4.11 Å. All Sr–Eu bond lengths are 4.14 Å. Eu is bonded to six equivalent Sr and six equivalent Eu atoms to form EuSr6Eu6 cuboctahedra that share corners with eighteen equivalent EuSr6Eu6 cuboctahedra, edges with six equivalent EuSr6Eu6 cuboctahedra, edges with twelve equivalent SrSr6Eu6 cuboctahedra, faces with eight equivalent EuSr6Eu6 cuboctahedra, and faces with twelve equivalent SrSr6Eu6 cuboctahedra. All Eu–Eu bond lengths are 4.11 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu2Si3Ni by Materials Project

Eu2NiSi3 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Eu is bonded to three equivalent Ni and nine Si atoms to form a mixture of face and edge-sharing EuSi9Ni3 cuboctahedra. All Eu–Ni bond lengths are 3.16 Å. There are three shorter (3.16 Å) and six longer (3.26 Å) Eu–Si bond lengths. Ni is bonded in a 9-coordinate geometry to six equivalent Eu and three equivalent Si atoms. All Ni–Si bond lengths are 2.33 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to six equivalent Eu and three equivalent Si atoms. All Si–Si bond lengths are 2.33 Å. In the second Si site, Si is bonded in a 9-coordinate geometry to six equivalent Eu and three equivalent Ni atoms. In the third Si site, Si is bonded in a 9-coordinate geometry to six equivalent Eu and three equivalent Si atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu3Mg by Materials Project

MgEu3 crystallizes in the orthorhombic Imm2 space group. The structure is two-dimensional and consists of two MgEu3 sheets oriented in the (0, 0, 1) direction. Mg is bonded in a body-centered cubic geometry to eight Eu atoms. There are a spread of Mg–Eu bond distances ranging from 3.44–3.64 Å. There are two inequivalent Eu sites. In the first Eu site, Eu is bonded in a 12-coordinate geometry to two equivalent Mg atoms. In the second Eu site, Eu is bonded in a 4-coordinate geometry to four equivalent Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on EuCo2SiGe by Materials Project

EuCo2GeSi crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. Eu is bonded in a 12-coordinate geometry to eight equivalent Co, four equivalent Ge, and four equivalent Si atoms. There are four shorter (3.19 Å) and four longer (3.28 Å) Eu–Co bond lengths. All Eu–Ge bond lengths are 3.11 Å. All Eu–Si bond lengths are 3.13 Å. Co is bonded in a 4-coordinate geometry to four equivalent Eu, two equivalent Ge, and two equivalent Si atoms. Both Co–Ge bond lengths are 2.35 Å. Both Co–Si bond lengths are 2.27 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Eu, four equivalent Co, and one Si atom. The Ge–Si bond length is 2.73 Å. Si is bonded in a 9-coordinate geometry to four equivalent Eu, four equivalent Co, and one Ge atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on EuSiNi2Ge by Materials Project

EuNi2GeSi crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. Eu is bonded in a 12-coordinate geometry to eight equivalent Ni, four equivalent Ge, and four equivalent Si atoms. There are four shorter (3.17 Å) and four longer (3.26 Å) Eu–Ni bond lengths. All Eu–Ge bond lengths are 3.16 Å. All Eu–Si bond lengths are 3.18 Å. Ni is bonded in a 12-coordinate geometry to four equivalent Eu, two equivalent Ge, and two equivalent Si atoms. Both Ni–Ge bond lengths are 2.39 Å. Both Ni–Si bond lengths are 2.31 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Eu, four equivalent Ni, and one Si atom. The Ge–Si bond length is 2.63 Å. Si is bonded in a 9-coordinate geometry to four equivalent Eu, four equivalent Ni, and one Ge atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu2Si3Au by Materials Project

Eu2AuSi3 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Eu+2.50+ is bonded to three equivalent Au1- and nine Si+1.33- atoms to form a mixture of face and edge-sharing EuSi9Au3 cuboctahedra. All Eu–Au bond lengths are 3.28 Å. There are three shorter (3.28 Å) and six longer (3.31 Å) Eu–Si bond lengths. Au1- is bonded in a distorted trigonal planar geometry to six equivalent Eu+2.50+ and three equivalent Si+1.33- atoms. All Au–Si bond lengths are 2.44 Å. There are three inequivalent Si+1.33- sites. In the first Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to six equivalent Eu+2.50+ and three equivalent Si+1.33- atoms. All Si–Si bond lengths are 2.44 Å. In the second Si+1.33- site, Si+1.33- is bonded in a distorted trigonal planar geometry to six equivalent Eu+2.50+ and three equivalent Au1- atoms. In the third Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to six equivalent Eu+2.50+ and three equivalent Si+1.33- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on EuWO5 by Materials Project

EuWO5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Eu is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Eu–O bond distances ranging from 2.36–2.54 Å. W is bonded in a distorted trigonal bipyramidal geometry to five O atoms. There are a spread of W–O bond distances ranging from 1.80–2.14 Å. There are five inequivalent O sites. In the first O site, O is bonded in a trigonal non-coplanar geometry to two equivalent Eu and one W atom. In the second O site, O is bonded in a distorted trigonal non-coplanar geometry to two equivalent Eu and one W atom. In the third O site, O is bonded in a 3-coordinate geometry to two equivalent Eu and one W atom. In the fourth O site, O is bonded in a linear geometry to one Eu and one W atom. In the fifth O site, O is bonded in a bent 150 degrees geometry to one Eu and one W atom.

36 MATERIALS SCIENCE↗
NASA NTRS2002

Ree in Shergottite Augites and Whole Rocks

Redox variations have been reported among the shergottites. Eu and Gd partitioning experiments designed for the LEW86010 angrite, to infer a range of fo2 for the shergottites have been used. Fo2 using equilibria between Fe-Ti oxides have been inferred. There is fairly good agreement between the Fe-Ti oxide determinations and the estimates from Eu anomalies in terms of which meteorites are more or less oxidized. The Eu anomaly technique and the Fe-Ti oxide technique both essentially show the same trend, with Shergotty and Zagami being the most oxidized and QUE94201 and DaG 476 being the most reduced. Thus, the variation in fo2 appears to be both real and substantive. However, although the redox trends indicated by the two techniques are similar, there is as much as a two log unit offset between the results. One explanation for this offset is that the Eu calibration used for the shergottites was actually designed for the LEW86010 angrite, a silica-undersaturated basalt whose pyroxene (diopside) compositions are rather extreme. To correct this, a set of experiments on the redox relationship of Eu partitioning relative to Sm and Gd for pyroxene and melt compositions more relevant to Martian meteorites were conducted. We have taken the experimentally determined relationship between D (sup Augite/melt) (Sm,Eu,Gd) and fO2 and applied it to augite Eu and Gd data for the basaltic Shergottites of as well as previously unreported augite Sm data.

Musselwhite, D. S.↗
NASA NTRS2002

REE in Shergottite Augites and Whole Rocks

Redox variations have been reported among the shergottites. Eu and Gd were used in partitioning experiments designed for the LEW86010 angrite, to infer a range of fO2 for the shergottites. Inferred fO2 using equilibria between Fe-Ti oxides was used. There is fairly good agreement between the Fe- Ti oxide determinations and the estimates from Eu anomalies in terms of which meteorites are more or less oxidized. The Eu anomaly technique and the Fe-Ti oxide technique both essentially show the same trend, with Shergotty and Zagami being the most oxidized and QUE94201 and DaG 476 being the most reduced. Thus, the variation in fO2 appears to be both real and substantive. However, although the redox trends indicated by the two techniques are similar, there is as much as a two log unit offset between the results of presented. One explanation for this offset is that the Eu calibration used for the shergottites was actually designed for the LEW86010 angrite, a silica-undersaturated basalt whose pyroxene (diopside) compositions are rather extreme. To correct this, a set of experiments were conducted on the redox relationship of Eu partitioning relative to Sm and Gd for pyroxene and melt compositions more relevant to Martian meteorites. We have taken the experimentally determined relationship between (Sm,Eu,Gd) and fO2 and applied it to augite Eu and Gd data for the basaltic Shergottites as well as previously unreported augite Sm data.

Musselwhite, D. S.↗
NASA NTRS2014

Expanding the REE Partitioning Database for Lunar Materials

Positive europium anomalies are ubiquitous in the plagioclase-rich rocks of the lunar highlands, and complementary negative Eu anomalies are found in most lunar basalts. This is taken as evidence of a large-scale differentation event, with crystallization of a global-scale lunar magma ocean (LMO) resulting in a plagioclase flotation crust and a mafic lunar interior from which mare basalts were later derived. However, the extent of the Eu anomaly in lunar rocks is variable. Some plagioclase grains in a lunar impact rock (60635) have been reported to display a negative Eu anomaly, or in some cases single grains display both positive and neagtive anomalies. Cathodoluminescence images reveal that some crystals have a negative anomaly in the core and positive at the rim, or vice versa, and the negative anomalies are not associated with crystal overgrowths. Oxygen fugacity is known to affect Eu partitioning into plagioclase, as under low fO2 conditions Eu can be divalent, and has an ionic radius similar to Ca2+ - significant in lunar samples where plagioclase compositions are predominantly anorthitic. However, there are very few experimental studies of rare earth element (REE) partitioning in plagioclase relevant to lunar magmatism, with only two plagioclase DEu measurements from experiments using lunar materials, and little data in low fO2 conditions relevant to the Moon. We report on REE partitioning experiments on lunar compositions. We investigate two lunar basaltic compositions, high-alumina basalt 14072 and impact melt breccia 60635. These samples span a large range of lunar surface bulk compositions. The experiments are carried out at variable fO2 in 1 bar gas mixing furnaces, and REE are analysed by and LA-ICP-MS. Our results not only greatly expand the existing plagioclase DREE database for lunar compositions, but also investigate the significance of fO2 in Eu partitioning, and in the interpretation of Eu anomalies in lunar materials.

Rapp, Jennifer F.↗
DOE OSTI2020

Materials Data on EuCoGe3 by Materials Project

EuCoGe3 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. Eu is bonded in a 12-coordinate geometry to five equivalent Co and twelve Ge atoms. There are one shorter (3.40 Å) and four longer (3.45 Å) Eu–Co bond lengths. There are a spread of Eu–Ge bond distances ranging from 3.15–3.31 Å. Co is bonded in a 5-coordinate geometry to five equivalent Eu and five Ge atoms. There are one shorter (2.30 Å) and four longer (2.36 Å) Co–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 2-coordinate geometry to four equivalent Eu, two equivalent Co, and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.79 Å. In the second Ge site, Ge is bonded in a 1-coordinate geometry to four equivalent Eu, one Co, and four equivalent Ge atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on EuAl2 by Materials Project

EuAl2 is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Eu is bonded in a 12-coordinate geometry to four equivalent Eu and twelve equivalent Al atoms. All Eu–Eu bond lengths are 3.54 Å. All Eu–Al bond lengths are 3.39 Å. Al is bonded to six equivalent Eu and six equivalent Al atoms to form a mixture of edge, face, and corner-sharing AlEu6Al6 cuboctahedra. All Al–Al bond lengths are 2.89 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu2(Ga3Ir)3 by Materials Project

Eu2(IrGa3)3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Eu is bonded in a 11-coordinate geometry to eleven Ga atoms. There are a spread of Eu–Ga bond distances ranging from 3.09–3.17 Å. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 8-coordinate geometry to eight Ga atoms. There are two shorter (2.63 Å) and six longer (2.64 Å) Ir–Ga bond lengths. In the second Ir site, Ir is bonded in a 8-coordinate geometry to eight Ga atoms. There are a spread of Ir–Ga bond distances ranging from 2.61–2.65 Å. There are four inequivalent Ga sites. In the first Ga site, Ga is bonded in a 3-coordinate geometry to two equivalent Eu, three Ir, and five Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.78–2.89 Å. In the second Ga site, Ga is bonded in a 3-coordinate geometry to three equivalent Eu, three Ir, and five Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.80–2.97 Å. In the third Ga site, Ga is bonded in a 10-coordinate geometry to two equivalent Eu, two equivalent Ir, and six Ga atoms. Both Ga–Ga bond lengths are 2.75 Å. In the fourth Ga site, Ga is bonded in a 10-coordinate geometry to two equivalent Eu, two equivalent Ir, and six Ga atoms. The Ga–Ga bond length is 2.73 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on EuCu9Sn4 by Materials Project

EuCu9Sn4 is Bergman Structure: Mg32(Al,Zn)49 Bergman-like structured and crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Eu is bonded in a 8-coordinate geometry to sixteen Cu and eight equivalent Sn atoms. There are eight shorter (3.60 Å) and eight longer (3.65 Å) Eu–Cu bond lengths. All Eu–Sn bond lengths are 3.52 Å. There are three inequivalent Cu sites. In the first Cu site, Cu is bonded in a 12-coordinate geometry to two equivalent Eu, six Cu, and four equivalent Sn atoms. There are a spread of Cu–Cu bond distances ranging from 2.54–2.76 Å. There are a spread of Cu–Sn bond distances ranging from 2.60–2.70 Å. In the second Cu site, Cu is bonded in a 12-coordinate geometry to two equivalent Eu, six Cu, and four equivalent Sn atoms. There are a spread of Cu–Cu bond distances ranging from 2.56–2.99 Å. There are two shorter (2.75 Å) and two longer (2.79 Å) Cu–Sn bond lengths. In the third Cu site, Cu is bonded in a cuboctahedral geometry to eight Cu and four equivalent Sn atoms. All Cu–Sn bond lengths are 2.77 Å. Sn is bonded in a 11-coordinate geometry to two equivalent Eu and nine Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu3As4 by Materials Project

Eu3As4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Eu2+ sites. In the first Eu2+ site, Eu2+ is bonded to eight As+1.50- atoms to form corner-sharing EuAs8 hexagonal bipyramids. There are a spread of Eu–As bond distances ranging from 3.09–3.22 Å. In the second Eu2+ site, Eu2+ is bonded in a 8-coordinate geometry to eight As+1.50- atoms. There are a spread of Eu–As bond distances ranging from 3.07–3.18 Å. In the third Eu2+ site, Eu2+ is bonded in a 8-coordinate geometry to eight As+1.50- atoms. There are a spread of Eu–As bond distances ranging from 3.06–3.20 Å. In the fourth Eu2+ site, Eu2+ is bonded in a 8-coordinate geometry to eight As+1.50- atoms. There are a spread of Eu–As bond distances ranging from 3.08–3.23 Å. In the fifth Eu2+ site, Eu2+ is bonded in a 8-coordinate geometry to eight As+1.50- atoms. There are a spread of Eu–As bond distances ranging from 3.06–3.19 Å. In the sixth Eu2+ site, Eu2+ is bonded in a 8-coordinate geometry to eight As+1.50- atoms. There are a spread of Eu–As bond distances ranging from 3.07–3.20 Å. There are eight inequivalent As+1.50- sites. In the first As+1.50- site, As+1.50- is bonded in a 8-coordinate geometry to six Eu2+ and two As+1.50- atoms. There are one shorter (2.47 Å) and one longer (2.61 Å) As–As bond lengths. In the second As+1.50- site, As+1.50- is bonded in a 7-coordinate geometry to six Eu2+ and one As+1.50- atom. The As–As bond length is 2.54 Å. In the third As+1.50- site, As+1.50- is bonded in a 8-coordinate geometry to six Eu2+ and two As+1.50- atoms. There are one shorter (2.45 Å) and one longer (2.59 Å) As–As bond lengths. In the fourth As+1.50- site, As+1.50- is bonded in a 7-coordinate geometry to six Eu2+ and one As+1.50- atom. In the fifth As+1.50- site, As+1.50- is bonded in a 7-coordinate geometry to six Eu2+ and one As+1.50- atom. The As–As bond length is 2.54 Å. In the sixth As+1.50- site, As+1.50- is bonded in a 8-coordinate geometry to six Eu2+ and two As+1.50- atoms. In the seventh As+1.50- site, As+1.50- is bonded in a 8-coordinate geometry to six Eu2+ and two As+1.50- atoms. In the eighth As+1.50- site, As+1.50- is bonded in a 7-coordinate geometry to six Eu2+ and one As+1.50- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu2Ga3Ir by Materials Project

Eu2IrGa3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Eu is bonded in a 12-coordinate geometry to three equivalent Ir and nine Ga atoms. There are two shorter (3.31 Å) and one longer (3.32 Å) Eu–Ir bond lengths. There are three shorter (3.13 Å) and six longer (3.34 Å) Eu–Ga bond lengths. Ir is bonded to six equivalent Eu and six Ga atoms to form IrEu6Ga6 cuboctahedra that share corners with twelve GaEu6Ga4Ir2 cuboctahedra, edges with six equivalent IrEu6Ga6 cuboctahedra, faces with two equivalent IrEu6Ga6 cuboctahedra, and faces with eighteen GaEu6Ga4Ir2 cuboctahedra. There are four shorter (2.69 Å) and two longer (2.70 Å) Ir–Ga bond lengths. There are two inequivalent Ga sites. In the first Ga site, Ga is bonded to six equivalent Eu, two equivalent Ir, and four equivalent Ga atoms to form distorted GaEu6Ga4Ir2 cuboctahedra that share corners with four equivalent IrEu6Ga6 cuboctahedra, corners with fourteen GaEu6Ga4Ir2 cuboctahedra, edges with six equivalent GaEu6Ga4Ir2 cuboctahedra, faces with six equivalent IrEu6Ga6 cuboctahedra, and faces with twelve equivalent GaEu6Ga4Ir2 cuboctahedra. There are two shorter (2.73 Å) and two longer (2.96 Å) Ga–Ga bond lengths. In the second Ga site, Ga is bonded to six equivalent Eu, two equivalent Ir, and four Ga atoms to form distorted GaEu6Ga4Ir2 cuboctahedra that share corners with four equivalent IrEu6Ga6 cuboctahedra, corners with fourteen GaEu6Ga4Ir2 cuboctahedra, edges with six equivalent GaEu6Ga4Ir2 cuboctahedra, faces with six equivalent IrEu6Ga6 cuboctahedra, and faces with twelve GaEu6Ga4Ir2 cuboctahedra. There are one shorter (2.71 Å) and one longer (2.98 Å) Ga–Ga bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on EuGe2Ir by Materials Project

EuIrGe2 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Eu is bonded in a 12-coordinate geometry to four equivalent Ir and ten Ge atoms. All Eu–Ir bond lengths are 3.36 Å. There are a spread of Eu–Ge bond distances ranging from 3.28–3.42 Å. Ir is bonded in a 9-coordinate geometry to four equivalent Eu and five Ge atoms. There are a spread of Ir–Ge bond distances ranging from 2.43–2.54 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 1-coordinate geometry to six equivalent Eu, one Ir, and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.59 Å. In the second Ge site, Ge is bonded in a 4-coordinate geometry to four equivalent Eu and four equivalent Ir atoms.

36 MATERIALS SCIENCE↗