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DOE OSTI2020

Materials Data on Hg2TeS by Materials Project

Hg2TeS is Clathrate-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded to three equivalent Te2- and one S2- atom to form corner-sharing HgTe3S tetrahedra. All Hg–Te bond lengths are 2.83 Å. The Hg–S bond length is 2.58 Å. In the second Hg2+ site, Hg2+ is bonded to one Te2- and three equivalent S2- atoms to form corner-sharing HgTeS3 tetrahedra. The Hg–Te bond length is 2.87 Å. All Hg–S bond lengths are 2.70 Å. Te2- is bonded to four Hg2+ atoms to form TeHg4 tetrahedra that share corners with six equivalent TeHg4 tetrahedra and corners with six equivalent SHg4 tetrahedra. S2- is bonded to four Hg2+ atoms to form SHg4 tetrahedra that share corners with six equivalent TeHg4 tetrahedra and corners with six equivalent SHg4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si by Materials Project

Si is Clathrate-like structured and crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are eight inequivalent Si sites. In the first Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.34–2.41 Å. In the second Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.32–2.37 Å. In the third Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra. The Si–Si bond length is 2.31 Å. In the fourth Si site, Si is bonded to four Si atoms to form a mixture of corner and edge-sharing SiSi4 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.41–2.46 Å. In the fifth Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra. The Si–Si bond length is 2.31 Å. In the sixth Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra. The Si–Si bond length is 2.33 Å. In the seventh Si site, Si is bonded to four Si atoms to form a mixture of distorted corner and edge-sharing SiSi4 tetrahedra. There are one shorter (2.41 Å) and two longer (2.46 Å) Si–Si bond lengths. In the eighth Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li3Fe2(SiO4)2 by Materials Project

Li3Fe2(SiO4)2 is Clathrate-derived structured and crystallizes in the monoclinic Pc space group. The structure is three-dimensional. there are six inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 trigonal pyramids that share a cornercorner with one LiO4 tetrahedra, corners with four FeO4 tetrahedra, corners with four SiO4 tetrahedra, and an edgeedge with one LiO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.98–2.16 Å. In the second Li1+ site, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with four FeO4 tetrahedra, and corners with four SiO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.92–2.06 Å. In the third Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with two FeO4 tetrahedra, corners with four SiO4 tetrahedra, a cornercorner with one LiO4 trigonal pyramid, an edgeedge with one FeO4 tetrahedra, and an edgeedge with one LiO4 trigonal pyramid. There are a spread of Li–O bond distances ranging from 1.99–2.10 Å. In the fourth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with two FeO4 tetrahedra, corners with four SiO4 tetrahedra, a cornercorner with one LiO4 trigonal pyramid, an edgeedge with one FeO4 tetrahedra, and an edgeedge with one LiO4 trigonal pyramid. There are a spread of Li–O bond distances ranging from 1.97–2.10 Å. In the fifth Li1+ site, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with four FeO4 tetrahedra, and corners with four SiO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.93–2.07 Å. In the sixth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 trigonal pyramids that share a cornercorner with one LiO4 tetrahedra, corners with four FeO4 tetrahedra, corners with four SiO4 tetrahedra, and an edgeedge with one LiO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.98–2.15 Å. There are four inequivalent Fe+2.50+ sites. In the first Fe+2.50+ site, Fe+2.50+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three LiO4 tetrahedra, corners with four SiO4 tetrahedra, corners with two equivalent LiO4 trigonal pyramids, and an edgeedge with one LiO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.96–2.08 Å. In the second Fe+2.50+ site, Fe+2.50+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three LiO4 tetrahedra, corners with four SiO4 tetrahedra, and corners with two equivalent LiO4 trigonal pyramids. There are a spread of Fe–O bond distances ranging from 1.89–1.97 Å. In the third Fe+2.50+ site, Fe+2.50+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three LiO4 tetrahedra, corners with four SiO4 tetrahedra, and corners with two equivalent LiO4 trigonal pyramids. There are a spread of Fe–O bond distances ranging from 1.89–1.97 Å. In the fourth Fe+2.50+ site, Fe+2.50+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three LiO4 tetrahedra, corners with four SiO4 tetrahedra, corners with two equivalent LiO4 trigonal pyramids, and an edgeedge with one LiO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.95–2.09 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three LiO4 tetrahedra, corners with four FeO4 tetrahedra, and corners with three LiO4 trigonal pyramids. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four FeO4 tetrahedra, corners with five LiO4 tetrahedra, and a cornercorner with one LiO4 trigonal pyramid. There are a spread of Si–O bond distances ranging from 1.64–1.67 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four FeO4 tetrahedra, corners with five LiO4 tetrahedra, and a cornercorner with one LiO4 trigonal pyramid. There are a spread of Si–O bond distances ranging from 1.64–1.67 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three LiO4 tetrahedra, corners with four FeO4 tetrahedra, and corners with three LiO4 trigonal pyramids. There are a spread of Si–O bond distances ranging from 1.63–1.68 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded to two Li1+, one Fe+2.50+, and one Si4+ atom to form a mixture of distorted edge and corner-sharing OLi2FeSi trigonal pyramids. In the second O2- site, O2- is bonded in a trigonal planar geometry to one Li1+, one Fe+2.50+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Fe+2.50+, and one Si4+ atom. In the fourth O2- site, O2- is bonded to two Li1+, one Fe+2.50+, and one Si4+ atom to form a mixture of distorted edge and corner-sharing OLi2FeSi tetrahedra. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to one Li1+, one Fe+2.50+, and one Si4+ atom. In the sixth O2- site, O2- is bonded to two Li1+, one Fe+2.50+, and one Si4+ atom to form a mixture of edge and corner-sharing OLi2FeSi tetrahedra. In the seventh O2- site, O2- is bonded to two Li1+, one Fe+2.50+, and one Si4+ atom to form corner-sharing OLi2FeSi tetrahedra. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Fe+2.50+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Fe+2.50+, and one Si4+ atom. In the tenth O2- site, O2- is bonded to two Li1+, one Fe+2.50+, and one Si4+ atom to form corner-sharing OLi2FeSi tetrahedra. In the eleventh O2- site, O2- is bonded to two Li1+, one Fe+2.50+, and one Si4+ atom to form a mixture of edge and corner-sharing OLi2FeSi tetrahedra. In the twelfth O2- site, O2- is bonded in a trigonal planar geometry to one Li1+, one Fe+2.50+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded to two Li1+, one Fe+2.50+, and one Si4+ atom to form a mixture of distorted edge and corner-sharing OLi2FeSi tetrahedra. In the fourteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Fe+2.50+, and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a trigonal planar geometry to one Li1+, one Fe+2.50+, and one Si4+ atom. In the sixteenth O2- site, O2- is bonded to two Li1+, one Fe+2.50+, and one Si4+ atom to form a mixture of distorted edge and corner-sharing OLi2FeSi trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZnCu2Sn(SeS)2 by Materials Project

Cu2ZnSnS2Se2 is Clathrate-derived structured and crystallizes in the orthorhombic Fmm2 space group. The structure is three-dimensional. Cu1+ is bonded to two equivalent Se2- and two equivalent S2- atoms to form CuSe2S2 tetrahedra that share corners with four equivalent CuSe2S2 tetrahedra, corners with four equivalent ZnSe2S2 tetrahedra, and corners with four equivalent SnSe2S2 tetrahedra. Both Cu–Se bond lengths are 2.44 Å. Both Cu–S bond lengths are 2.30 Å. Zn2+ is bonded to two equivalent Se2- and two equivalent S2- atoms to form ZnSe2S2 tetrahedra that share corners with four equivalent SnSe2S2 tetrahedra and corners with eight equivalent CuSe2S2 tetrahedra. Both Zn–Se bond lengths are 2.48 Å. Both Zn–S bond lengths are 2.39 Å. Sn4+ is bonded to two equivalent Se2- and two equivalent S2- atoms to form SnSe2S2 tetrahedra that share corners with four equivalent ZnSe2S2 tetrahedra and corners with eight equivalent CuSe2S2 tetrahedra. Both Sn–Se bond lengths are 2.59 Å. Both Sn–S bond lengths are 2.50 Å. Se2- is bonded to two equivalent Cu1+, one Zn2+, and one Sn4+ atom to form SeZnCu2Sn tetrahedra that share corners with four equivalent SeZnCu2Sn tetrahedra and corners with eight equivalent SZnCu2Sn tetrahedra. S2- is bonded to two equivalent Cu1+, one Zn2+, and one Sn4+ atom to form SZnCu2Sn tetrahedra that share corners with four equivalent SZnCu2Sn tetrahedra and corners with eight equivalent SeZnCu2Sn tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd2GaAg(SeS)2 by Materials Project

AgCd2GaS2Se2 is Clathrate-derived structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Ag1+ is bonded to one Se2- and three S2- atoms to form AgSeS3 tetrahedra that share corners with two equivalent AgSeS3 tetrahedra, corners with four equivalent GaSeS3 tetrahedra, and corners with six CdSe3S tetrahedra. The Ag–Se bond length is 2.64 Å. There are two shorter (2.58 Å) and one longer (2.68 Å) Ag–S bond lengths. There are two inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to three Se2- and one S2- atom to form CdSe3S tetrahedra that share corners with three equivalent AgSeS3 tetrahedra, corners with three equivalent GaSeS3 tetrahedra, and corners with six CdSe3S tetrahedra. There are two shorter (2.59 Å) and one longer (2.72 Å) Cd–Se bond lengths. The Cd–S bond length is 2.63 Å. In the second Cd2+ site, Cd2+ is bonded to three Se2- and one S2- atom to form CdSe3S tetrahedra that share corners with three equivalent AgSeS3 tetrahedra, corners with three equivalent GaSeS3 tetrahedra, and corners with six CdSe3S tetrahedra. There are one shorter (2.59 Å) and two longer (2.69 Å) Cd–Se bond lengths. The Cd–S bond length is 2.54 Å. Ga3+ is bonded to one Se2- and three S2- atoms to form GaSeS3 tetrahedra that share corners with two equivalent GaSeS3 tetrahedra, corners with four equivalent AgSeS3 tetrahedra, and corners with six CdSe3S tetrahedra. The Ga–Se bond length is 2.50 Å. There are one shorter (2.29 Å) and two longer (2.47 Å) Ga–S bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to one Ag1+ and three Cd2+ atoms to form SeCd3Ag tetrahedra that share corners with six SeCd3Ag tetrahedra and corners with six SCdGaAg2 tetrahedra. In the second Se2- site, Se2- is bonded to three Cd2+ and one Ga3+ atom to form SeCd3Ga tetrahedra that share corners with six SeCd3Ag tetrahedra and corners with six SCdGaAg2 tetrahedra. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent Ag1+, one Cd2+, and one Ga3+ atom to form SCdGaAg2 tetrahedra that share corners with six SeCd3Ag tetrahedra and corners with six SCdGaAg2 tetrahedra. In the second S2- site, S2- is bonded to one Ag1+, one Cd2+, and two equivalent Ga3+ atoms to form SCdGa2Ag tetrahedra that share corners with six SeCd3Ag tetrahedra and corners with six SCdGaAg2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZnCu2SnSe3S by Materials Project

Cu2ZnSn(Se0.75S0.25)4 is Clathrate-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to three Se2- and one S2- atom to form CuSe3S tetrahedra that share corners with four equivalent CuSe3S tetrahedra, corners with four equivalent ZnSe3S tetrahedra, and corners with four equivalent SnSe3S tetrahedra. There are two shorter (2.44 Å) and one longer (2.45 Å) Cu–Se bond lengths. The Cu–S bond length is 2.31 Å. In the second Cu1+ site, Cu1+ is bonded to three Se2- and one S2- atom to form CuSe3S tetrahedra that share corners with four equivalent CuSe3S tetrahedra, corners with four equivalent ZnSe3S tetrahedra, and corners with four equivalent SnSe3S tetrahedra. There are two shorter (2.43 Å) and one longer (2.44 Å) Cu–Se bond lengths. The Cu–S bond length is 2.30 Å. Zn2+ is bonded to three Se2- and one S2- atom to form ZnSe3S tetrahedra that share corners with four equivalent SnSe3S tetrahedra and corners with eight CuSe3S tetrahedra. There are two shorter (2.49 Å) and one longer (2.50 Å) Zn–Se bond lengths. The Zn–S bond length is 2.38 Å. Sn4+ is bonded to three Se2- and one S2- atom to form SnSe3S tetrahedra that share corners with four equivalent ZnSe3S tetrahedra and corners with eight CuSe3S tetrahedra. There are two shorter (2.61 Å) and one longer (2.62 Å) Sn–Se bond lengths. The Sn–S bond length is 2.51 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two Cu1+, one Zn2+, and one Sn4+ atom to form SeZnCu2Sn tetrahedra that share corners with four equivalent SZnCu2Sn tetrahedra and corners with eight SeZnCu2Sn tetrahedra. In the second Se2- site, Se2- is bonded to two Cu1+, one Zn2+, and one Sn4+ atom to form SeZnCu2Sn tetrahedra that share corners with four equivalent SZnCu2Sn tetrahedra and corners with eight SeZnCu2Sn tetrahedra. In the third Se2- site, Se2- is bonded to two Cu1+, one Zn2+, and one Sn4+ atom to form SeZnCu2Sn tetrahedra that share corners with four equivalent SZnCu2Sn tetrahedra and corners with eight SeZnCu2Sn tetrahedra. S2- is bonded to two Cu1+, one Zn2+, and one Sn4+ atom to form SZnCu2Sn tetrahedra that share corners with twelve SeZnCu2Sn tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd4FeCu10(SnSe4)5 by Materials Project

FeCu10Cd4(SnSe4)5 is Clathrate-derived structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Fe3+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with four equivalent SnSe4 tetrahedra and corners with eight CuSe4 tetrahedra. All Fe–Se bond lengths are 2.46 Å. There are five inequivalent Cu+1.10+ sites. In the first Cu+1.10+ site, Cu+1.10+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four CuSe4 tetrahedra, corners with four CdSe4 tetrahedra, and corners with four SnSe4 tetrahedra. There are three shorter (2.44 Å) and one longer (2.45 Å) Cu–Se bond lengths. In the second Cu+1.10+ site, Cu+1.10+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four CuSe4 tetrahedra, corners with four CdSe4 tetrahedra, and corners with four SnSe4 tetrahedra. There are three shorter (2.44 Å) and one longer (2.45 Å) Cu–Se bond lengths. In the third Cu+1.10+ site, Cu+1.10+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four CuSe4 tetrahedra, corners with four equivalent CdSe4 tetrahedra, and corners with four SnSe4 tetrahedra. All Cu–Se bond lengths are 2.44 Å. In the fourth Cu+1.10+ site, Cu+1.10+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share a cornercorner with one CdSe4 tetrahedra, corners with three equivalent FeSe4 tetrahedra, corners with four CuSe4 tetrahedra, and corners with four equivalent SnSe4 tetrahedra. There are a spread of Cu–Se bond distances ranging from 2.46–2.50 Å. In the fifth Cu+1.10+ site, Cu+1.10+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share a cornercorner with one FeSe4 tetrahedra, corners with three equivalent CdSe4 tetrahedra, corners with four CuSe4 tetrahedra, and corners with four SnSe4 tetrahedra. There are a spread of Cu–Se bond distances ranging from 2.44–2.49 Å. There are two inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to four Se2- atoms to form CdSe4 tetrahedra that share corners with four SnSe4 tetrahedra and corners with eight CuSe4 tetrahedra. There are two shorter (2.69 Å) and two longer (2.70 Å) Cd–Se bond lengths. In the second Cd2+ site, Cd2+ is bonded to four Se2- atoms to form CdSe4 tetrahedra that share corners with four SnSe4 tetrahedra and corners with eight CuSe4 tetrahedra. There are two shorter (2.68 Å) and two longer (2.69 Å) Cd–Se bond lengths. There are three inequivalent Sn+3.60+ sites. In the first Sn+3.60+ site, Sn+3.60+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with two equivalent FeSe4 tetrahedra, corners with two equivalent CdSe4 tetrahedra, and corners with eight CuSe4 tetrahedra. There are a spread of Sn–Se bond distances ranging from 2.64–2.67 Å. In the second Sn+3.60+ site, Sn+3.60+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with four equivalent CdSe4 tetrahedra and corners with eight CuSe4 tetrahedra. There are two shorter (2.62 Å) and two longer (2.63 Å) Sn–Se bond lengths. In the third Sn+3.60+ site, Sn+3.60+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with four CdSe4 tetrahedra and corners with eight CuSe4 tetrahedra. There are a spread of Sn–Se bond distances ranging from 2.62–2.64 Å. There are ten inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to one Fe3+, two Cu+1.10+, and one Sn+3.60+ atom to form corner-sharing SeFeCu2Sn tetrahedra. In the second Se2- site, Se2- is bonded to two Cu+1.10+, one Cd2+, and one Sn+3.60+ atom to form corner-sharing SeCdCu2Sn tetrahedra. In the third Se2- site, Se2- is bonded to two equivalent Cu+1.10+, one Cd2+, and one Sn+3.60+ atom to form corner-sharing SeCdCu2Sn tetrahedra. In the fourth Se2- site, Se2- is bonded to two Cu+1.10+, one Cd2+, and one Sn+3.60+ atom to form corner-sharing SeCdCu2Sn tetrahedra. In the fifth Se2- site, Se2- is bonded to two Cu+1.10+, one Cd2+, and one Sn+3.60+ atom to form corner-sharing SeCdCu2Sn tetrahedra. In the sixth Se2- site, Se2- is bonded to two Cu+1.10+, one Cd2+, and one Sn+3.60+ atom to form corner-sharing SeCdCu2Sn tetrahedra. In the seventh Se2- site, Se2- is bonded to two Cu+1.10+, one Cd2+, and one Sn+3.60+ atom to form corner-sharing SeCdCu2Sn tetrahedra. In the eighth Se2- site, Se2- is bonded to two Cu+1.10+, one Cd2+, and one Sn+3.60+ atom to form corner-sharing SeCdCu2Sn tetrahedra. In the ninth Se2- site, Se2- is bonded to two Cu+1.10+, one Cd2+, and one Sn+3.60+ atom to form corner-sharing SeCdCu2Sn tetrahedra. In the tenth Se2- site, Se2- is bonded to one Fe3+, two equivalent Cu+1.10+, and one Sn+3.60+ atom to form corner-sharing SeFeCu2Sn tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ga2CuAg(TeSe)2 by Materials Project

AgCuGa2(TeSe)2 is Clathrate-derived structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Ag1+ is bonded to two equivalent Te2- and two equivalent Se2- atoms to form AgTe2Se2 tetrahedra that share corners with four equivalent CuTe2Se2 tetrahedra and corners with eight GaTe2Se2 tetrahedra. Both Ag–Te bond lengths are 2.75 Å. Both Ag–Se bond lengths are 2.69 Å. Cu1+ is bonded to two equivalent Te2- and two equivalent Se2- atoms to form CuTe2Se2 tetrahedra that share corners with four equivalent AgTe2Se2 tetrahedra and corners with eight GaTe2Se2 tetrahedra. Both Cu–Te bond lengths are 2.57 Å. Both Cu–Se bond lengths are 2.51 Å. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to two equivalent Te2- and two equivalent Se2- atoms to form GaTe2Se2 tetrahedra that share corners with four equivalent AgTe2Se2 tetrahedra, corners with four equivalent CuTe2Se2 tetrahedra, and corners with four equivalent GaTe2Se2 tetrahedra. Both Ga–Te bond lengths are 2.65 Å. Both Ga–Se bond lengths are 2.48 Å. In the second Ga3+ site, Ga3+ is bonded to two equivalent Te2- and two equivalent Se2- atoms to form GaTe2Se2 tetrahedra that share corners with four equivalent AgTe2Se2 tetrahedra, corners with four equivalent CuTe2Se2 tetrahedra, and corners with four equivalent GaTe2Se2 tetrahedra. Both Ga–Te bond lengths are 2.66 Å. Both Ga–Se bond lengths are 2.51 Å. Te2- is bonded to one Ag1+, one Cu1+, and two Ga3+ atoms to form TeGa2CuAg tetrahedra that share corners with four equivalent TeGa2CuAg tetrahedra and corners with eight equivalent SeGa2CuAg tetrahedra. Se2- is bonded to one Ag1+, one Cu1+, and two Ga3+ atoms to form SeGa2CuAg tetrahedra that share corners with four equivalent SeGa2CuAg tetrahedra and corners with eight equivalent TeGa2CuAg tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZnCdCu4(SnS4)2 by Materials Project

Cu4CdZn(SnS4)2 is Clathrate-derived structured and crystallizes in the tetragonal P-42m space group. The structure is three-dimensional. Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share corners with two equivalent CdS4 tetrahedra, corners with two equivalent ZnS4 tetrahedra, corners with four equivalent CuS4 tetrahedra, and corners with four SnS4 tetrahedra. There are two shorter (2.31 Å) and two longer (2.34 Å) Cu–S bond lengths. Cd2+ is bonded to four equivalent S2- atoms to form CdS4 tetrahedra that share corners with four equivalent SnS4 tetrahedra and corners with eight equivalent CuS4 tetrahedra. All Cd–S bond lengths are 2.55 Å. Zn2+ is bonded to four equivalent S2- atoms to form ZnS4 tetrahedra that share corners with four equivalent SnS4 tetrahedra and corners with eight equivalent CuS4 tetrahedra. All Zn–S bond lengths are 2.41 Å. There are two inequivalent Sn4+ sites. In the first Sn4+ site, Sn4+ is bonded to four equivalent S2- atoms to form SnS4 tetrahedra that share corners with four equivalent CdS4 tetrahedra and corners with eight equivalent CuS4 tetrahedra. All Sn–S bond lengths are 2.47 Å. In the second Sn4+ site, Sn4+ is bonded to four equivalent S2- atoms to form SnS4 tetrahedra that share corners with four equivalent ZnS4 tetrahedra and corners with eight equivalent CuS4 tetrahedra. All Sn–S bond lengths are 2.48 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent Cu1+, one Cd2+, and one Sn4+ atom to form corner-sharing SCdCu2Sn tetrahedra. In the second S2- site, S2- is bonded to two equivalent Cu1+, one Zn2+, and one Sn4+ atom to form corner-sharing SZnCu2Sn tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZnCu2SnSeS3 by Materials Project

Cu2ZnSnSeS3 is Clathrate-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to one Se2- and three S2- atoms to form CuSeS3 tetrahedra that share corners with four equivalent CuSeS3 tetrahedra, corners with four equivalent ZnSeS3 tetrahedra, and corners with four equivalent SnSeS3 tetrahedra. The Cu–Se bond length is 2.43 Å. There are a spread of Cu–S bond distances ranging from 2.31–2.33 Å. In the second Cu1+ site, Cu1+ is bonded to one Se2- and three S2- atoms to form CuSeS3 tetrahedra that share corners with four equivalent CuSeS3 tetrahedra, corners with four equivalent ZnSeS3 tetrahedra, and corners with four equivalent SnSeS3 tetrahedra. The Cu–Se bond length is 2.42 Å. There are two shorter (2.31 Å) and one longer (2.32 Å) Cu–S bond lengths. Zn2+ is bonded to one Se2- and three S2- atoms to form ZnSeS3 tetrahedra that share corners with four equivalent SnSeS3 tetrahedra and corners with eight CuSeS3 tetrahedra. The Zn–Se bond length is 2.48 Å. There are one shorter (2.36 Å) and two longer (2.37 Å) Zn–S bond lengths. Sn4+ is bonded to one Se2- and three S2- atoms to form SnSeS3 tetrahedra that share corners with four equivalent ZnSeS3 tetrahedra and corners with eight CuSeS3 tetrahedra. The Sn–Se bond length is 2.59 Å. There are two shorter (2.48 Å) and one longer (2.49 Å) Sn–S bond lengths. Se2- is bonded to two Cu1+, one Zn2+, and one Sn4+ atom to form SeZnCu2Sn tetrahedra that share corners with twelve SZnCu2Sn tetrahedra. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded to two Cu1+, one Zn2+, and one Sn4+ atom to form SZnCu2Sn tetrahedra that share corners with four equivalent SeZnCu2Sn tetrahedra and corners with eight SZnCu2Sn tetrahedra. In the second S2- site, S2- is bonded to two Cu1+, one Zn2+, and one Sn4+ atom to form SZnCu2Sn tetrahedra that share corners with four equivalent SeZnCu2Sn tetrahedra and corners with eight SZnCu2Sn tetrahedra. In the third S2- site, S2- is bonded to two Cu1+, one Zn2+, and one Sn4+ atom to form SZnCu2Sn tetrahedra that share corners with four equivalent SeZnCu2Sn tetrahedra and corners with eight SZnCu2Sn tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li3Mn2(SiO4)2 by Materials Project

Li3Mn2(SiO4)2 is Clathrate-derived structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with two equivalent LiO4 tetrahedra, corners with two equivalent MnO4 tetrahedra, corners with four SiO4 tetrahedra, and an edgeedge with one MnO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.91–2.07 Å. In the second Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with two equivalent SiO4 tetrahedra, corners with four equivalent LiO4 tetrahedra, corners with four equivalent MnO4 tetrahedra, and an edgeedge with one SiO4 tetrahedra. There are two shorter (2.07 Å) and two longer (2.08 Å) Li–O bond lengths. Mn+2.50+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with four LiO4 tetrahedra, corners with four SiO4 tetrahedra, and an edgeedge with one LiO4 tetrahedra. There are a spread of Mn–O bond distances ranging from 1.96–2.08 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent LiO4 tetrahedra, corners with four equivalent MnO4 tetrahedra, and an edgeedge with one LiO4 tetrahedra. There is two shorter (1.64 Å) and two longer (1.66 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent MnO4 tetrahedra and corners with six LiO4 tetrahedra. There is two shorter (1.64 Å) and two longer (1.67 Å) Si–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Mn+2.50+, and one Si4+ atom. In the second O2- site, O2- is bonded to two Li1+, one Mn+2.50+, and one Si4+ atom to form edge-sharing OLi2MnSi tetrahedra. In the third O2- site, O2- is bonded in a trigonal planar geometry to one Li1+, one Mn+2.50+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Li1+, one Mn+2.50+, and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CdFe4Cu10(SnSe4)5 by Materials Project

Fe4Cu10Cd(SnSe4)5 is Clathrate-derived structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with four SnSe4 tetrahedra and corners with eight CuSe4 tetrahedra. There are one shorter (2.41 Å) and three longer (2.42 Å) Fe–Se bond lengths. In the second Fe3+ site, Fe3+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with four SnSe4 tetrahedra and corners with eight CuSe4 tetrahedra. There are three shorter (2.42 Å) and one longer (2.43 Å) Fe–Se bond lengths. There are five inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share a cornercorner with one FeSe4 tetrahedra, corners with three equivalent CdSe4 tetrahedra, corners with four CuSe4 tetrahedra, and corners with four equivalent SnSe4 tetrahedra. There are a spread of Cu–Se bond distances ranging from 2.39–2.41 Å. In the second Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent FeSe4 tetrahedra, corners with four CuSe4 tetrahedra, and corners with four SnSe4 tetrahedra. There are three shorter (2.44 Å) and one longer (2.45 Å) Cu–Se bond lengths. In the third Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four FeSe4 tetrahedra, corners with four CuSe4 tetrahedra, and corners with four SnSe4 tetrahedra. There are two shorter (2.44 Å) and two longer (2.45 Å) Cu–Se bond lengths. In the fourth Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share a cornercorner with one CdSe4 tetrahedra, corners with three equivalent FeSe4 tetrahedra, corners with four CuSe4 tetrahedra, and corners with four SnSe4 tetrahedra. There are a spread of Cu–Se bond distances ranging from 2.42–2.45 Å. In the fifth Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four FeSe4 tetrahedra, corners with four CuSe4 tetrahedra, and corners with four SnSe4 tetrahedra. There are two shorter (2.44 Å) and two longer (2.45 Å) Cu–Se bond lengths. Cd2+ is bonded to four Se2- atoms to form CdSe4 tetrahedra that share corners with four equivalent SnSe4 tetrahedra and corners with eight CuSe4 tetrahedra. All Cd–Se bond lengths are 2.66 Å. There are three inequivalent Sn+3.20+ sites. In the first Sn+3.20+ site, Sn+3.20+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with two equivalent FeSe4 tetrahedra, corners with two equivalent CdSe4 tetrahedra, and corners with eight CuSe4 tetrahedra. There are a spread of Sn–Se bond distances ranging from 2.62–2.65 Å. In the second Sn+3.20+ site, Sn+3.20+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with four FeSe4 tetrahedra and corners with eight CuSe4 tetrahedra. There are one shorter (2.68 Å) and three longer (2.69 Å) Sn–Se bond lengths. In the third Sn+3.20+ site, Sn+3.20+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with four equivalent FeSe4 tetrahedra and corners with eight CuSe4 tetrahedra. There are two shorter (2.69 Å) and two longer (2.70 Å) Sn–Se bond lengths. There are ten inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to one Fe3+, two Cu1+, and one Sn+3.20+ atom to form corner-sharing SeFeCu2Sn tetrahedra. In the second Se2- site, Se2- is bonded to two Cu1+, one Cd2+, and one Sn+3.20+ atom to form corner-sharing SeCdCu2Sn tetrahedra. In the third Se2- site, Se2- is bonded to one Fe3+, two Cu1+, and one Sn+3.20+ atom to form corner-sharing SeFeCu2Sn tetrahedra. In the fourth Se2- site, Se2- is bonded to one Fe3+, two equivalent Cu1+, and one Sn+3.20+ atom to form corner-sharing SeFeCu2Sn tetrahedra. In the fifth Se2- site, Se2- is bonded to one Fe3+, two Cu1+, and one Sn+3.20+ atom to form corner-sharing SeFeCu2Sn tetrahedra. In the sixth Se2- site, Se2- is bonded to two equivalent Cu1+, one Cd2+, and one Sn+3.20+ atom to form corner-sharing SeCdCu2Sn tetrahedra. In the seventh Se2- site, Se2- is bonded to one Fe3+, two Cu1+, and one Sn+3.20+ atom to form corner-sharing SeFeCu2Sn tetrahedra. In the eighth Se2- site, Se2- is bonded to one Fe3+, two Cu1+, and one Sn+3.20+ atom to form corner-sharing SeFeCu2Sn tetrahedra. In the ninth Se2- site, Se2- is bonded to one Fe3+, two Cu1+, and one Sn+3.20+ atom to form corner-sharing SeFeCu2Sn tetrahedra. In the tenth Se2- site, Se2- is bonded to one Fe3+, two Cu1+, and one Sn+3.20+ atom to form corner-sharing SeFeCu2Sn tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zn3Fe2Cu10(SnSe4)5 by Materials Project

Fe2Cu10Zn3(SnSe4)5 is Clathrate-derived structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Fe3+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with four SnSe4 tetrahedra and corners with eight CuSe4 tetrahedra. There are two shorter (2.43 Å) and two longer (2.44 Å) Fe–Se bond lengths. There are five inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four CuSe4 tetrahedra, corners with four ZnSe4 tetrahedra, and corners with four SnSe4 tetrahedra. All Cu–Se bond lengths are 2.43 Å. In the second Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share a cornercorner with one FeSe4 tetrahedra, corners with three equivalent ZnSe4 tetrahedra, corners with four CuSe4 tetrahedra, and corners with four SnSe4 tetrahedra. There are a spread of Cu–Se bond distances ranging from 2.42–2.44 Å. In the third Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four CuSe4 tetrahedra, corners with four ZnSe4 tetrahedra, and corners with four equivalent SnSe4 tetrahedra. All Cu–Se bond lengths are 2.43 Å. In the fourth Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share a cornercorner with one ZnSe4 tetrahedra, corners with three equivalent FeSe4 tetrahedra, corners with four CuSe4 tetrahedra, and corners with four SnSe4 tetrahedra. There are a spread of Cu–Se bond distances ranging from 2.43–2.45 Å. In the fifth Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent FeSe4 tetrahedra, corners with four CuSe4 tetrahedra, and corners with four SnSe4 tetrahedra. There are three shorter (2.44 Å) and one longer (2.45 Å) Cu–Se bond lengths. There are two inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to four Se2- atoms to form ZnSe4 tetrahedra that share corners with four SnSe4 tetrahedra and corners with eight CuSe4 tetrahedra. All Zn–Se bond lengths are 2.50 Å. In the second Zn2+ site, Zn2+ is bonded to four Se2- atoms to form ZnSe4 tetrahedra that share corners with four equivalent SnSe4 tetrahedra and corners with eight CuSe4 tetrahedra. All Zn–Se bond lengths are 2.50 Å. There are three inequivalent Sn+3.60+ sites. In the first Sn+3.60+ site, Sn+3.60+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with two equivalent FeSe4 tetrahedra, corners with two equivalent ZnSe4 tetrahedra, and corners with eight CuSe4 tetrahedra. There are one shorter (2.65 Å) and three longer (2.66 Å) Sn–Se bond lengths. In the second Sn+3.60+ site, Sn+3.60+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with four ZnSe4 tetrahedra and corners with eight CuSe4 tetrahedra. There are three shorter (2.63 Å) and one longer (2.64 Å) Sn–Se bond lengths. In the third Sn+3.60+ site, Sn+3.60+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with four equivalent FeSe4 tetrahedra and corners with eight CuSe4 tetrahedra. There are two shorter (2.67 Å) and two longer (2.68 Å) Sn–Se bond lengths. There are ten inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to one Fe3+, two Cu1+, and one Sn+3.60+ atom to form corner-sharing SeFeCu2Sn tetrahedra. In the second Se2- site, Se2- is bonded to two Cu1+, one Zn2+, and one Sn+3.60+ atom to form corner-sharing SeZnCu2Sn tetrahedra. In the third Se2- site, Se2- is bonded to two Cu1+, one Zn2+, and one Sn+3.60+ atom to form corner-sharing SeZnCu2Sn tetrahedra. In the fourth Se2- site, Se2- is bonded to two Cu1+, one Zn2+, and one Sn+3.60+ atom to form corner-sharing SeZnCu2Sn tetrahedra. In the fifth Se2- site, Se2- is bonded to one Fe3+, two equivalent Cu1+, and one Sn+3.60+ atom to form corner-sharing SeFeCu2Sn tetrahedra. In the sixth Se2- site, Se2- is bonded to two Cu1+, one Zn2+, and one Sn+3.60+ atom to form corner-sharing SeZnCu2Sn tetrahedra. In the seventh Se2- site, Se2- is bonded to two equivalent Cu1+, one Zn2+, and one Sn+3.60+ atom to form corner-sharing SeZnCu2Sn tetrahedra. In the eighth Se2- site, Se2- is bonded to two Cu1+, one Zn2+, and one Sn+3.60+ atom to form corner-sharing SeZnCu2Sn tetrahedra. In the ninth Se2- site, Se2- is bonded to one Fe3+, two Cu1+, and one Sn+3.60+ atom to form corner-sharing SeFeCu2Sn tetrahedra. In the tenth Se2- site, Se2- is bonded to one Fe3+, two Cu1+, and one Sn+3.60+ atom to form corner-sharing SeFeCu2Sn tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si by Materials Project

Si is Clathrate-like structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are nine inequivalent Si sites. In the first Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.35–2.40 Å. In the second Si site, Si is bonded to four Si atoms to form a mixture of edge and corner-sharing SiSi4 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.33–2.39 Å. In the third Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra. There are one shorter (2.33 Å) and three longer (2.35 Å) Si–Si bond lengths. In the fourth Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra. There are a spread of Si–Si bond distances ranging from 2.38–2.48 Å. In the fifth Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra. The Si–Si bond length is 2.38 Å. In the sixth Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra. Both Si–Si bond lengths are 2.32 Å. In the seventh Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra. The Si–Si bond length is 2.41 Å. In the eighth Si site, Si is bonded to four Si atoms to form a mixture of edge and corner-sharing SiSi4 tetrahedra. In the ninth Si site, Si is bonded to four Si atoms to form corner-sharing SiSi4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Gas Hydrate Film Growth in Microfluidic Channels for Carbon Dioxide Capture and Sequestration Applications

Gas or clathrate hydrates are a solid, crystalline compound composed of water and guest molecules that typically form at high pressure and low temperature conditions. Carbon dioxide (CO2) hydrates may be involved in several carbon dioxide capture and sequestration (CCS) applications, including CO2 pipeline transportation and CO2 offshore sequestration. Within these applications, the formation mechanism and kinetics must be well understood to manage the CCS processes, either by preventing or promoting hydrate formation. In this work, a high-pressure glass microfluidic reactor is used in tandem with visual microscopy and in-situ Raman spectroscopy to study both the morphological and kinetic behavior of gas hydrate crystals. Subcooling, pressure, and CO2 flow rate are investigated for their impact on the thickening behavior of pure CO2 hydrates, with flow rate being the only parameter to have a significant effect. Visual and Raman spectroscopy evidence show that both a dense hydrate layer and a porous hydrate layer form, and the latter may provide a path for mass transfer to continue hydrate crystallization. A first principles mass transfer model is developed to describe CO2 hydrate crystal thickening at the interface between gas and water. The impacts of gas impurities and channel wettability are also studied. This method is further applied to investigate the conversion of methane hydrate to CO2 hydrate for combined energy recovery and methane hydrate formation. The authors acknowledge the US Department of Energy Basic Energy Science award # DE-SC0022162.

Wadsworth, Lindsey [Colorado School of Mines, Gold↗
DOE OSTI2020

A Moderator Test Station at ORNL

Oak Ridge National Laboratory (ORNL) hosts two world-leading slow neutron sources, the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR), and is currently developing the technical design for a Second Target Station (STS) for the SNS. Upon completion of the STS project, ORNL will be uniquely positioned to optimize each of its three neutron sources, the SNS First Target Station (FTS), the STS, and HFIR, in a complementary way. Among the essential aspects of a reimagined FTS and the current STS concept are high-brightness parahydrogen moderators—moderators which are optimized for high per-unit-area neutron brightness rather than integrated-across-large-area neutron intensity. The high-brightness moderators proposed for the STS will significantly outperform the coupled moderators currently on the FTS for appropriately optimized neutron beamlines, provided the moderating hydrogen is converted to near-equilibrium levels of parahydrogen (approximately 99.8% at 20 K). The original FTS moderators, by contrast, were conservatively designed to be relatively insensitive to the exact ortho:para ratio, with a consequent loss in performance. As a result, a redesign of the FTS moderators assuming fully converted parahydrogen could result in significant performance improvements on the FTS coupled moderators, and more consistent performance over time for all hydrogen moderators. This “parahydrogen problem” is a long-standing challenge for the effective implementation of hydrogen cold moderators at high-power neutron sources. In addition, the development of new moderator concepts, whether based on previously unused materials, structured heterogeneous arrays, or even simply on changes in overall shape and size is significantly restricted at a large-scale production facility intended to use the neutron beams so produced. Accordingly, moderators for production neutron sources are often designed in a very conservative, low-risk fashion, even though this compromises the absolute neutronic performance. Advanced moderator concepts worthy of study include features that could not be tested without redesigning and redeploying the entire existing reflector, shielding, and neutron beamline installation, making such development efforts far more expensive than building a stand-alone test facility. We propose a Moderator Test Station (MTS) at the SNS with which we will verify such performance gains and test new moderator concepts. These concepts include both high-brightness and large-volume parahydrogen moderators, as well as moderators with tailored ortho:para hydrogen levels, heterogeneous moderator concepts such as the convoluted moderator or pelletized moderators, and moderators made of materials like ammonia, ethane, and oxygen clathrates, which have not been widely tested let alone deployed at neutron source facilities.

42 ENGINEERING↗
DOE OSTI2026

Towards libraries of different ultrasmall amorphous silica cage topologies

Cage topology controlled at the nanometer length scale is expected to enable original functionalities, e.g., in catalysis and therapeutics. Cages are fundamental structural motifs of clathrates and their topological duals, Frank-Kasper phases, and are constituents of mesoporous silica frameworks. However, with one exception, they have not been synthesized as discrete particles. By varying reactant ratios of surfactant, oil, and silane, we report the discovery of 5(12)6(2) and 5(12)6(8) amorphous silica polyhedra, each coexisting with the previously identified 5(12) cage, using combined cryo-transmission electron microscopy (cryo-TEM) and single-particle reconstruction (SPR). Notably, the 5(12)6(8) polyhedron represents a topology not previously observed in mesoporous silica frameworks. Control over structural features is demonstrated, and insights into cage formation mechanisms are provided. Structural outcomes are summarized in a ternary morphology diagram alongside prior results, bridging serendipitous discovery and intentional design of silica cages displaying a level of control over silica polymerization rivaling nature.

Jang, Dong June [Department of Materials Science a↗
DOE OSTI2021

Autogenous formation and smart behaviors of nitrite- and nitrate-intercalated layered double hydroxides (LDHs) in Portland cement-metakaolin-dolomite blends

In this work, the influence of sodium nitrite (NaNO{sub 2}) and sodium nitrate (NaNO{sub 3}) corrosion inhibitors on the composition, structure, and chloride binding behaviors of layered double hydroxides (LDHs) formed in ternary ordinary Portland cement-metakaolin-dolomite (OPC-MK-DM) systems is studied. The results show that the nitrite and nitrate anions are preferably intercalated in the CaAl LDHs (AFm phases), but not in the MgAl LDHs (hydrotalcite-type phases) due to its limited formation in these ternary cementitious systems cured at ambient temperature. The autogenously formed nitrate- and nitrite-AFm phases are decomposed upon chloride exposure accompanied by Friedel's salts formation, potentially releasing corrosion inhibitive ions to the pore solution in a progressive manner. The NaNO{sub 2} and NaNO{sub 3} incorporation in ternary OPC-MK-DM binders marginally lowers chloride binding capacity but reduces its penetration resistance mainly due to pore coarsening. Nevertheless, a strong linear correlation can be established between the water-soluble and total chloride contents in ternary OPC-MK-DM systems, regardless of OPC replacement level and corrosion inhibitor incorporation.

36 MATERIALS SCIENCE↗