Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Ca”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ca(H8O5)2 by Materials Project

Ca(H8O5)2 crystallizes in the monoclinic Pc space group. The structure is two-dimensional and consists of two Ca(H8O5)2 sheets oriented in the (0, 0, 1) direction. Ca is bonded in a body-centered cubic geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.46–2.55 Å. There are sixteen inequivalent H sites. In the first H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.65 Å) H–O bond length. In the second H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the third H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the fourth H site, H is bonded in a single-bond geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.70 Å) H–O bond length. In the fifth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the sixth H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.03 Å) and one longer (1.61 Å) H–O bond length. In the seventh H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the eighth H site, H is bonded in a single-bond geometry to two O atoms. There is one shorter (1.00 Å) and one longer (1.74 Å) H–O bond length. In the ninth H site, H is bonded in a single-bond geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.73 Å) H–O bond length. In the tenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the eleventh H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.03 Å) and one longer (1.62 Å) H–O bond length. In the twelfth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the thirteenth H site, H is bonded in a single-bond geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.71 Å) H–O bond length. In the fourteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the fifteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the sixteenth H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.03 Å) and one longer (1.63 Å) H–O bond length. There are ten inequivalent O sites. In the first O site, O is bonded in a 5-coordinate geometry to four H and one O atom. The O–O bond length is 1.51 Å. In the second O site, O is bonded in a 2-coordinate geometry to four H and one O atom. In the third O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the fourth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the fifth O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and two H atoms. In the sixth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the seventh O site, O is bonded in a distorted water-like geometry to one Ca and two H atoms. In the eighth O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and two H atoms. In the ninth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the tenth O site, O is bonded in a water-like geometry to one Ca and two H atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(H8O5)2 by Materials Project

Ca(H8O5)2 crystallizes in the monoclinic Pc space group. The structure is two-dimensional and consists of two Ca(H8O5)2 sheets oriented in the (0, 0, 1) direction. Ca is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.49–2.55 Å. There are sixteen inequivalent H sites. In the first H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.63 Å) H–O bond length. In the second H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the third H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.62 Å) H–O bond length. In the fourth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the fifth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the sixth H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.63 Å) H–O bond length. In the seventh H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.67 Å) H–O bond length. In the eighth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.01 Å. In the ninth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the tenth H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.61 Å) H–O bond length. In the eleventh H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.63 Å) H–O bond length. In the twelfth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the thirteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the fourteenth H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.03 Å) and one longer (1.61 Å) H–O bond length. In the fifteenth H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.63 Å) H–O bond length. In the sixteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. There are ten inequivalent O sites. In the first O site, O is bonded in a 5-coordinate geometry to four H and one O atom. The O–O bond length is 1.49 Å. In the second O site, O is bonded in a 5-coordinate geometry to four H and one O atom. In the third O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the fourth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the fifth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the sixth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the seventh O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the eighth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the ninth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the tenth O site, O is bonded in a water-like geometry to one Ca and two H atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(H8O5)2 by Materials Project

Ca(H8O5)2 crystallizes in the monoclinic Cc space group. The structure is two-dimensional and consists of two Ca(H8O5)2 sheets oriented in the (0, 0, 1) direction. Ca is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.47–2.58 Å. There are sixteen inequivalent H sites. In the first H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.66 Å) H–O bond length. In the second H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the third H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the fourth H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.64 Å) H–O bond length. In the fifth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the sixth H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.64 Å) H–O bond length. In the seventh H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.65 Å) H–O bond length. In the eighth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the ninth H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.67 Å) H–O bond length. In the tenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the eleventh H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the twelfth H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.62 Å) H–O bond length. In the thirteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the fourteenth H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.60 Å) H–O bond length. In the fifteenth H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.62 Å) H–O bond length. In the sixteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. There are ten inequivalent O sites. In the first O site, O is bonded in a 5-coordinate geometry to four H and one O atom. The O–O bond length is 1.49 Å. In the second O site, O is bonded in a 5-coordinate geometry to four H and one O atom. In the third O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the fourth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the fifth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the sixth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the seventh O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the eighth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the ninth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the tenth O site, O is bonded in a water-like geometry to one Ca and two H atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(H8O5)2 by Materials Project

Ca(H8O5)2 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of two Ca(H8O5)2 sheets oriented in the (0, 0, 1) direction. Ca is bonded in a distorted body-centered cubic geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.45–2.79 Å. There are sixteen inequivalent H sites. In the first H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the second H site, H is bonded in a linear geometry to two O atoms. There is one shorter (1.03 Å) and one longer (1.58 Å) H–O bond length. In the third H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the fourth H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.66 Å) H–O bond length. In the fifth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. In the sixth H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.03 Å) and one longer (1.56 Å) H–O bond length. In the seventh H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.97 Å. In the eighth H site, H is bonded in a linear geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.58 Å) H–O bond length. In the ninth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the tenth H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.66 Å) H–O bond length. In the eleventh H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.69 Å) H–O bond length. In the twelfth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the thirteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the fourteenth H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.61 Å) H–O bond length. In the fifteenth H site, H is bonded in a distorted single-bond geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.66 Å) H–O bond length. In the sixteenth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. There are ten inequivalent O sites. In the first O site, O is bonded in a 5-coordinate geometry to four H and one O atom. The O–O bond length is 1.49 Å. In the second O site, O is bonded in a 5-coordinate geometry to four H and one O atom. In the third O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the fourth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the fifth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the sixth O site, O is bonded in a distorted water-like geometry to one Ca and two H atoms. In the seventh O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the eighth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the ninth O site, O is bonded in a water-like geometry to one Ca and two H atoms. In the tenth O site, O is bonded in a water-like geometry to one Ca and two H atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca by Materials Project

Ca is alpha La structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded to twelve Ca atoms to form a mixture of edge, corner, and face-sharing CaCa12 cuboctahedra. There are six shorter (3.89 Å) and six longer (3.91 Å) Ca–Ca bond lengths. In the second Ca site, Ca is bonded to twelve Ca atoms to form a mixture of edge, corner, and face-sharing CaCa12 cuboctahedra. All Ca–Ca bond lengths are 3.89 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Association between soil organic carbon and calcium in acidic grassland soils from Point Reyes National Seashore, CA

Organo-mineral and organo-metal associations play an important role in the retention and accumulation of soil organic carbon (SOC). Recent studies have demonstrated a positive correlation between calcium (Ca) and SOC content in a range of soil types. However, most of these studies have focused on soils that contain calcium carbonate (pH > 6). To assess the importance of Ca-SOC associations in lower pH soils, we investigated their physical and chemical interaction in the grassland soils of Point Reyes National Seashore (CA, USA) at a range of spatial scales. Multivariate analyses of our bulk soil characterisation dataset showed a strong correlation between exchangeable Ca (Ca Exch ; 5–8.3 c.mol c kg –1 ) and SOC (0.6–4%) content. Additionally, linear combination fitting (LCF) of bulk Ca K-edge X-ray absorption near-edge structure (XANES) spectra revealed that Ca was predominantly associated with organic carbon across all samples. Scanning transmission X-ray microscopy near-edge X-ray absorption fine structure spectroscopy (STXM C/Ca NEXAFS) showed that Ca had a strong spatial correlation with C at the microscale. The STXM C NEXAFS K-edge spectra indicated that SOC had a higher abundance of aromatic/olefinic and phenolic C functional groups when associated with Ca, relative to C associated with Fe. In regions of high Ca-C association, the STXM C NEXAFS spectra were similar to the spectrum from lignin, with moderate changes in peak intensities and positions that are consistent with oxidative C transformation. Through this association, Ca thus seems to be preferentially associated with plant-like organic matter that has undergone some oxidative transformation, at depth in acidic grassland soils of California. Our study highlights the importance of Ca-SOC complexation in acidic grassland soils and provides a conceptual model of its contribution to SOC preservation, a research area that has previously been unexplored.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Materials Data on Ca(Pr2Se3)4 by Materials Project

Ca(Pr2Se3)4 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. Ca is bonded to eight Se atoms to form distorted CaSe8 hexagonal bipyramids that share corners with eight PrSe8 hexagonal bipyramids, edges with four PrSe8 hexagonal bipyramids, and faces with eight PrSe8 hexagonal bipyramids. There are a spread of Ca–Se bond distances ranging from 3.01–3.24 Å. There are eight inequivalent Pr sites. In the first Pr site, Pr is bonded to eight Se atoms to form distorted PrSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven PrSe8 hexagonal bipyramids, an edgeedge with one CaSe8 hexagonal bipyramid, edges with three PrSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.02–3.23 Å. In the second Pr site, Pr is bonded to eight Se atoms to form distorted PrSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven PrSe8 hexagonal bipyramids, edges with four PrSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.02–3.22 Å. In the third Pr site, Pr is bonded to eight Se atoms to form distorted PrSe8 hexagonal bipyramids that share corners with two equivalent CaSe8 hexagonal bipyramids, corners with six PrSe8 hexagonal bipyramids, edges with four PrSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.02–3.22 Å. In the fourth Pr site, Pr is bonded to eight Se atoms to form distorted PrSe8 hexagonal bipyramids that share corners with two equivalent CaSe8 hexagonal bipyramids, corners with six PrSe8 hexagonal bipyramids, edges with four PrSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.03–3.22 Å. In the fifth Pr site, Pr is bonded to eight Se atoms to form distorted PrSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven PrSe8 hexagonal bipyramids, an edgeedge with one CaSe8 hexagonal bipyramid, edges with three PrSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.03–3.23 Å. In the sixth Pr site, Pr is bonded to eight Se atoms to form distorted PrSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven PrSe8 hexagonal bipyramids, edges with four PrSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.01–3.22 Å. In the seventh Pr site, Pr is bonded to eight Se atoms to form distorted PrSe8 hexagonal bipyramids that share corners with eight PrSe8 hexagonal bipyramids, edges with two equivalent CaSe8 hexagonal bipyramids, edges with two PrSe8 hexagonal bipyramids, and faces with eight PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.03–3.22 Å. In the eighth Pr site, Pr is bonded to eight Se atoms to form distorted PrSe8 hexagonal bipyramids that share corners with eight PrSe8 hexagonal bipyramids, edges with four PrSe8 hexagonal bipyramids, faces with two equivalent CaSe8 hexagonal bipyramids, and faces with six PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.03–3.21 Å. There are twelve inequivalent Se sites. In the first Se site, Se is bonded to one Ca and five Pr atoms to form distorted SeCaPr5 octahedra that share corners with fifteen SeCaPr5 octahedra, edges with six SeCaPr5 octahedra, and faces with five SePr6 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the second Se site, Se is bonded to one Ca and five Pr atoms to form a mixture of distorted edge, face, and corner-sharing SeCaPr5 octahedra. The corner-sharing octahedra tilt angles range from 17–51°. In the third Se site, Se is bonded to one Ca and five Pr atoms to form a mixture of distorted edge, face, and corner-sharing SeCaPr5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the fourth Se site, Se is bonded to six Pr atoms to form a mixture of distorted edge, face, and corner-sharing SePr6 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the fifth Se site, Se is bonded to six Pr atoms to form a mixture of distorted edge, face, and corner-sharing SePr6 octahedra. The corner-sharing octahedra tilt angles range from 16–51°. In the sixth Se site, Se is bonded to one Ca and five Pr atoms to form a mixture of distorted edge, face, and corner-sharing SeCaPr5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the seventh Se site, Se is bonded to one Ca and five Pr atoms to form a mixture of distorted edge, face, and corner-sharing SeCaPr5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the eighth Se site, Se is bonded to one Ca and five Pr atoms to form a mixture of distorted edge, face, and corner-sharing SeCaPr5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the ninth Se site, Se is bonded to one Ca and five Pr atoms to form a mixture of distorted edge, face, and corner-sharing SeCaPr5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the tenth Se site, Se is bonded to six Pr atoms to form distorted SePr6 octahedra that share corners with fifteen SeCaPr5 octahedra, edges with six SeCaPr5 octahedra, and faces with five SePr6 octahedra. The corner-sharing octahedra tilt angles range from 16–50°. In the eleventh Se site, Se is bonded to one Ca and five Pr atoms to form a mixture of distorted edge, face, and corner-sharing SeCaPr5 octahedra. The corner-sharing octahedra tilt angles range from 17–51°. In the twelfth Se site, Se is bonded to six Pr atoms to form a mixture of distorted edge, face, and corner-sharing SePr6 octahedra. The corner-sharing octahedra tilt angles range from 16–51°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(Ce2Se3)4 by Materials Project

Ca(Ce2Se3)4 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. Ca is bonded to eight Se atoms to form distorted CaSe8 hexagonal bipyramids that share corners with eight CeSe8 hexagonal bipyramids, edges with four CeSe8 hexagonal bipyramids, and faces with eight CeSe8 hexagonal bipyramids. There are a spread of Ca–Se bond distances ranging from 2.99–3.19 Å. There are eight inequivalent Ce sites. In the first Ce site, Ce is bonded to eight Se atoms to form distorted CeSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven CeSe8 hexagonal bipyramids, edges with four CeSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven CeSe8 hexagonal bipyramids. There are a spread of Ce–Se bond distances ranging from 3.00–3.17 Å. In the second Ce site, Ce is bonded to eight Se atoms to form distorted CeSe8 hexagonal bipyramids that share corners with two equivalent CaSe8 hexagonal bipyramids, corners with six CeSe8 hexagonal bipyramids, edges with four CeSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven CeSe8 hexagonal bipyramids. There are a spread of Ce–Se bond distances ranging from 2.99–3.17 Å. In the third Ce site, Ce is bonded to eight Se atoms to form distorted CeSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven CeSe8 hexagonal bipyramids, an edgeedge with one CaSe8 hexagonal bipyramid, edges with three CeSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven CeSe8 hexagonal bipyramids. There are a spread of Ce–Se bond distances ranging from 2.99–3.17 Å. In the fourth Ce site, Ce is bonded to eight Se atoms to form distorted CeSe8 hexagonal bipyramids that share corners with two equivalent CaSe8 hexagonal bipyramids, corners with six CeSe8 hexagonal bipyramids, edges with four CeSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven CeSe8 hexagonal bipyramids. There are a spread of Ce–Se bond distances ranging from 2.99–3.16 Å. In the fifth Ce site, Ce is bonded to eight Se atoms to form distorted CeSe8 hexagonal bipyramids that share corners with eight CeSe8 hexagonal bipyramids, edges with two equivalent CaSe8 hexagonal bipyramids, edges with two CeSe8 hexagonal bipyramids, and faces with eight CeSe8 hexagonal bipyramids. There are four shorter (3.00 Å) and four longer (3.16 Å) Ce–Se bond lengths. In the sixth Ce site, Ce is bonded to eight Se atoms to form distorted CeSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven CeSe8 hexagonal bipyramids, edges with four CeSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven CeSe8 hexagonal bipyramids. There are a spread of Ce–Se bond distances ranging from 2.99–3.17 Å. In the seventh Ce site, Ce is bonded to eight Se atoms to form distorted CeSe8 hexagonal bipyramids that share corners with eight CeSe8 hexagonal bipyramids, edges with four CeSe8 hexagonal bipyramids, faces with two equivalent CaSe8 hexagonal bipyramids, and faces with six CeSe8 hexagonal bipyramids. There are four shorter (3.01 Å) and four longer (3.16 Å) Ce–Se bond lengths. In the eighth Ce site, Ce is bonded to eight Se atoms to form distorted CeSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven CeSe8 hexagonal bipyramids, an edgeedge with one CaSe8 hexagonal bipyramid, edges with three CeSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven CeSe8 hexagonal bipyramids. There are a spread of Ce–Se bond distances ranging from 2.99–3.17 Å. There are twelve inequivalent Se sites. In the first Se site, Se is bonded to one Ca and five Ce atoms to form distorted SeCaCe5 octahedra that share corners with fifteen SeCaCe5 octahedra, edges with six SeCaCe5 octahedra, and faces with five SeCe6 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the second Se site, Se is bonded to one Ca and five Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeCaCe5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the third Se site, Se is bonded to one Ca and five Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeCaCe5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the fourth Se site, Se is bonded to six Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeCe6 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the fifth Se site, Se is bonded to six Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeCe6 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the sixth Se site, Se is bonded to one Ca and five Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeCaCe5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the seventh Se site, Se is bonded to one Ca and five Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeCaCe5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the eighth Se site, Se is bonded to one Ca and five Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeCaCe5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the ninth Se site, Se is bonded to one Ca and five Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeCaCe5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the tenth Se site, Se is bonded to six Ce atoms to form distorted SeCe6 octahedra that share corners with fifteen SeCaCe5 octahedra, edges with six SeCaCe5 octahedra, and faces with five SeCe6 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the eleventh Se site, Se is bonded to one Ca and five Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeCaCe5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the twelfth Se site, Se is bonded to six Ce atoms to form a mixture of distorted face, edge, and corner-sharing SeCe6 octahedra. The corner-sharing octahedra tilt angles range from 17–50°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(BO4)2 by Materials Project

Ca(BO4)2 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one Ca(BO4)2 sheet oriented in the (0, 1, 1) direction. Ca is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Ca–O bond distances ranging from 2.38–2.71 Å. There are two inequivalent B sites. In the first B site, B is bonded in a tetrahedral geometry to four O atoms. There are a spread of B–O bond distances ranging from 1.41–1.47 Å. In the second B site, B is bonded in a tetrahedral geometry to four O atoms. There are a spread of B–O bond distances ranging from 1.43–1.46 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and one B atom. In the second O site, O is bonded in a distorted single-bond geometry to one Ca and one B atom. In the third O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and one B atom. In the fourth O site, O is bonded in a single-bond geometry to one Ca and one B atom. In the fifth O site, O is bonded in a single-bond geometry to one B atom. In the sixth O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and one B atom. In the seventh O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and one B atom. In the eighth O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and one B atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(NO5)2 by Materials Project

Ca(NO5)2 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of two Ca(NO5)2 ribbons oriented in the (1, 0, 0) direction. Ca is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.39–2.88 Å. There are two inequivalent N sites. In the first N site, N is bonded in a trigonal planar geometry to three O atoms. There are a spread of N–O bond distances ranging from 1.22–1.31 Å. In the second N site, N is bonded in a trigonal planar geometry to three O atoms. There are a spread of N–O bond distances ranging from 1.23–1.29 Å. There are ten inequivalent O sites. In the first O site, O is bonded in a water-like geometry to one Ca and one N atom. In the second O site, O is bonded in a water-like geometry to one Ca and one O atom. The O–O bond length is 1.33 Å. In the third O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and one O atom. The O–O bond length is 1.23 Å. In the fourth O site, O is bonded in a water-like geometry to one Ca and one N atom. In the fifth O site, O is bonded in a bent 120 degrees geometry to one Ca and one O atom. The O–O bond length is 1.28 Å. In the sixth O site, O is bonded in a 3-coordinate geometry to two equivalent Ca and one N atom. In the seventh O site, O is bonded in a bent 120 degrees geometry to two O atoms. In the eighth O site, O is bonded in a single-bond geometry to one N atom. In the ninth O site, O is bonded in a distorted L-shaped geometry to one Ca and one N atom. In the tenth O site, O is bonded in a single-bond geometry to one N atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Role of Eu-Doping in the Electron Transport Behavior in the Zintl Thermoelectric Ca 5-x-y Yb x Eu y Al 2 Sb 6 System

A series of Eu-doped Zintl compounds belonging to theCa 5-x-y Yb x Eu y Al 2 Sb 6 (x = 0, 1.12; 0 ≤ y ≤ 0.63(2)) system have been successfully synthesized by both the arc-melting and the molten Pb-flux methods. All of the five title compounds initially crystallized in the Ca 5 Ga 2 As 6 -type phase (space group Pbam, Z = 2, Pearson code oP26) and maintained their original structure even after the post-heat treatment, unlike the recently reported n-type Zintl analogues in the Ca 5-x-y Yb x RE y Al 2 Sb 6 (RE = Pr, Nd, Sm) systems, which underwent a phase transition from the Ca 5 Ga 2 As 6 -type to the Ca 5 Al 2 Bi 6 -type phase after annealing. This research aimed to understand the origin of the structural preference of the title Ca 5-x-y Yb x Eu y Al 2 Sb 6 system, whether it was affected by the valence electron count or the cationic size. Electrical transport property measurements showed an increase in electrical conductivities and a decrease of Seebeck coefficients for Ca 4.89(1) Eu 0.11 Al 2 Sb 6 , Ca 4.82(1) Eu 0.18 Al 2 Sb 6 , and Ca 4.62(1) Eu 0.38 Al 2 Sb 6 , compared to the parental compound Ca 5 Al 2 Sb 6 . Hole effect measurements proved that these changes should be attributed to the reduced carrier concentration and enhanced carrier mobility. The comprehensive density functional theory calculations including electron density map analysis for the hypothetical model Ca 4.5 Eu 0.5 Al 2 Sb 6 revealed that the polarity between Al and Sb forming the anionic frameworks decreased as the Eu-dopants were introduced, which eventually affected the carrier mobility in the anionic frameworks. Thermal conductivity measurements proved that the Eu-doping successfully lowered the lattice thermal conductivity because of the enhanced atomic disordering. In conclusion, the magnetization measurements for Ca 4.37(2) Eu 0.63 Al 2 Sb 6 showed a typical Curie–Weiss behavior with weak antiferromagnetic nearest-neighbor interactions with θ p = -5.07 K.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(BO4)3 by Materials Project

Ca(BO4)3 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of two Ca(BO4)3 clusters. Ca is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.21–2.99 Å. There are three inequivalent B sites. In the first B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.35–1.40 Å. In the second B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.29–1.55 Å. In the third B site, B is bonded in a trigonal planar geometry to three O atoms. There is one shorter (1.36 Å) and two longer (1.38 Å) B–O bond length. There are twelve inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the second O site, O is bonded in a single-bond geometry to one B atom. In the third O site, O is bonded in a linear geometry to one Ca and one O atom. The O–O bond length is 1.33 Å. In the fourth O site, O is bonded in a single-bond geometry to one O atom. The O–O bond length is 1.23 Å. In the fifth O site, O is bonded in a single-bond geometry to one O atom. The O–O bond length is 1.23 Å. In the sixth O site, O is bonded in a bent 120 degrees geometry to one Ca and one B atom. In the seventh O site, O is bonded in a bent 150 degrees geometry to one Ca and one O atom. In the eighth O site, O is bonded in a distorted single-bond geometry to one B and one O atom. In the ninth O site, O is bonded in a bent 120 degrees geometry to one Ca and one B atom. In the tenth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the eleventh O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and one B atom. In the twelfth O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and one O atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(BO4)3 by Materials Project

Ca(BO4)3 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of two Ca(BO4)3 clusters. Ca is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Ca–O bond distances ranging from 2.30–2.81 Å. There are three inequivalent B sites. In the first B site, B is bonded in a trigonal planar geometry to three O atoms. All B–O bond lengths are 1.37 Å. In the second B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.42–1.61 Å. In the third B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.42–1.56 Å. There are twelve inequivalent O sites. In the first O site, O is bonded in a distorted water-like geometry to one Ca and one B atom. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and one B atom. In the third O site, O is bonded in a single-bond geometry to one B atom. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and one B atom. In the fifth O site, O is bonded in a single-bond geometry to one O atom. The O–O bond length is 1.23 Å. In the sixth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the seventh O site, O is bonded in a bent 150 degrees geometry to one Ca and one O atom. In the eighth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the ninth O site, O is bonded in a single-bond geometry to one O atom. The O–O bond length is 1.23 Å. In the tenth O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent Ca and two B atoms. In the eleventh O site, O is bonded in a bent 150 degrees geometry to one Ca and one O atom. In the twelfth O site, O is bonded in a single-bond geometry to one B atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(BO3)3 by Materials Project

Ca(BO3)3 crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of one Ca(BO3)3 ribbon oriented in the (1, 0, 0) direction. Ca is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.43–2.79 Å. There are three inequivalent B sites. In the first B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.36–1.40 Å. In the second B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.42–1.58 Å. In the third B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.41–1.54 Å. There are nine inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and two B atoms. In the third O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent Ca and two B atoms. In the fourth O site, O is bonded in a single-bond geometry to one B atom. In the fifth O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and one B atom. In the sixth O site, O is bonded in a distorted water-like geometry to one Ca and one B atom. In the seventh O site, O is bonded in a distorted single-bond geometry to two equivalent Ca and one B atom. In the eighth O site, O is bonded in a single-bond geometry to one B atom. In the ninth O site, O is bonded in a single-bond geometry to one Ca atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(ReO5)2 by Materials Project

Ca(ReO5)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ca is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.36–2.66 Å. There are two inequivalent Re sites. In the first Re site, Re is bonded in a tetrahedral geometry to four O atoms. There are a spread of Re–O bond distances ranging from 1.73–1.81 Å. In the second Re site, Re is bonded in a tetrahedral geometry to four O atoms. There is one shorter (1.73 Å) and three longer (1.76 Å) Re–O bond length. There are ten inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Re atom. In the second O site, O is bonded in a bent 120 degrees geometry to two equivalent Ca atoms. In the third O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and one Re atom. In the fourth O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and one Re atom. In the fifth O site, O is bonded in a linear geometry to one Ca and one Re atom. In the sixth O site, O is bonded in a linear geometry to one Ca and one Re atom. In the seventh O site, O is bonded in a single-bond geometry to one Re atom. In the eighth O site, O is bonded in a single-bond geometry to one Re atom. In the ninth O site, O is bonded in a single-bond geometry to one Ca atom. In the tenth O site, O is bonded in a bent 150 degrees geometry to one Ca and one Re atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(ClO2)2 by Materials Project

Ca(O2Cl)2 crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of one Ca(O2Cl)2 ribbon oriented in the (1, 0, 0) direction. Ca is bonded in a 5-coordinate geometry to five O and one Cl atom. There are a spread of Ca–O bond distances ranging from 2.28–2.62 Å. The Ca–Cl bond length is 3.02 Å. There are four inequivalent O sites. In the first O site, O is bonded in a trigonal planar geometry to two equivalent Ca and one Cl atom. The O–Cl bond length is 1.67 Å. In the second O site, O is bonded in a bent 120 degrees geometry to one Ca and one O atom. The O–O bond length is 1.27 Å. In the third O site, O is bonded in a bent 120 degrees geometry to one Ca and one Cl atom. The O–Cl bond length is 1.63 Å. In the fourth O site, O is bonded in a bent 120 degrees geometry to one Ca and one O atom. There are two inequivalent Cl sites. In the first Cl site, Cl is bonded in a distorted bent 120 degrees geometry to one Ca and one O atom. In the second Cl site, Cl is bonded in a distorted single-bond geometry to one O atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

The role of Ca-bridged organic matter in an alkaline soil, as revealed by multimodal chemical imaging

Mineral–organic matter (OM) studies have predominantly focused on acidic soils that are abundant in iron (Fe) oxides and aluminum (Al) oxides. We have probed mineral–OM interactions in an alkaline or calcareous soil of the Aridisols class. Unlike the role of Fe and Al, the role of Ca-minerals (particularly calcite), which are ubiquitous in alkaline soils, in OM sequestration is not well understood. Multiple recent model studies with aqueous Ca2+ or synthetic calcite and a suite of OM compounds have shown Ca-OM assemblages to be spatially correlated with calcite at the microscale. To study the chemical state of both Ca and Fe and their competing role in soil organic matter (SOM) stabilization, we performed laboratory characterization using x-ray diffraction, Mössbauer spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy, and scanning transmission electron microscopy, alongside synchrotron-based microscale chemical imaging using scanning transmission x-ray microscopy combined with near-edge x-ray absorption fine structure. Ca mineral–organic associations were found to be ubiquitous in this system and are likely critical for understanding SOM stabilization/degradation in alkaline soils. From our findings on mineralogy, speciation, and the nature of Ca-OM bridging, we identified differences in C and Ca chemistry based on the relative location of OM to Ca minerals. The OM near the calcite crystal was enriched in lipid and protein moieties, Ca-OM next to Fe minerals displayed a strong contribution from aromatic compounds, while on the surface of microbes, the carbonate was believed to be of microbial in origin, as also suggested by preliminary works reporting on the formation of amorphous calcite or nano-calcite. In Ca-OM admixed with carbonate, it was difficult to distinguish Ca-associated OM from amorphous calcite or nano-calcite.

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

Coupling of Ca 2+ and voltage activation in BK channels through the αB helix/voltage sensor interface

Large-conductance Ca 2+ and voltage-activated K + (BK) channels control membrane excitability in many cell types. BK channels are tetrameric. Each subunit is composed of a voltage sensor domain (VSD), a central pore-gate domain, and a large cytoplasmic domain (CTD) that contains the Ca 2+ sensors. While it is known that BK channels are activated by voltage and Ca 2+ , and that voltage and Ca 2+ activations interact, less is known about the mechanisms involved. In this work we explore these mechanisms by examining the gating contribution of an interface formed between the VSDs and the αB helices located at the top of the CTDs. Proline mutations in the αB helix greatly decreased voltage activation while having negligible effects on gating currents. Analysis with the Horrigan, Cui, and Aldrich model indicated a decreased coupling between voltage sensors and pore gate. Proline mutations decreased Ca 2+ activation for both Ca 2+ bowl and RCK1 Ca 2+ sites, suggesting that both high-affinity Ca 2+ sites transduce their effect, at least in part, through the αB helix. Mg 2+ activation also decreased. The crystal structure of the CTD with proline mutation L390P showed a flattening of the first helical turn in the αB helix compared to wild type, without other notable differences in the CTD, indicating that structural changes from the mutation were confined to the αB helix. These findings indicate that an intact αB helix/VSD interface is required for effective coupling of Ca 2+ binding and voltage depolarization to pore opening and that shared Ca 2+ and voltage transduction pathways involving the αB helix may be involved.

59 BASIC BIOLOGICAL SCIENCES↗