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DOE OSTI2020

Materials Data on YZr2Ni15 by Materials Project

YZr2Ni15 crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. Y is bonded in a 12-coordinate geometry to sixteen Ni atoms. There are a spread of Y–Ni bond distances ranging from 2.80–2.99 Å. There are two inequivalent Zr sites. In the first Zr site, Zr is bonded in a 12-coordinate geometry to sixteen Ni atoms. There are a spread of Zr–Ni bond distances ranging from 2.78–2.91 Å. In the second Zr site, Zr is bonded in a 12-coordinate geometry to sixteen Ni atoms. There are a spread of Zr–Ni bond distances ranging from 2.79–2.92 Å. There are nine inequivalent Ni sites. In the first Ni site, Ni is bonded to one Y, two equivalent Zr, and nine Ni atoms to form distorted NiYZr2Ni9 cuboctahedra that share corners with eighteen NiYZr2Ni9 cuboctahedra, edges with six NiYZr2Ni9 cuboctahedra, faces with eighteen NiYZr2Ni9 cuboctahedra, and faces with four equivalent NiY3ZrNi12 tetrahedra. There are a spread of Ni–Ni bond distances ranging from 2.35–2.79 Å. In the second Ni site, Ni is bonded to two equivalent Y, one Zr, and nine Ni atoms to form distorted NiY2ZrNi9 cuboctahedra that share corners with eighteen NiYZr2Ni9 cuboctahedra, corners with two equivalent NiY3ZrNi12 tetrahedra, edges with six NiYZr2Ni9 cuboctahedra, faces with eighteen NiYZr2Ni9 cuboctahedra, and faces with three equivalent NiY3ZrNi12 tetrahedra. There are a spread of Ni–Ni bond distances ranging from 2.35–2.89 Å. In the third Ni site, Ni is bonded to three Zr and nine Ni atoms to form distorted NiZr3Ni9 cuboctahedra that share corners with eighteen NiYZr2Ni9 cuboctahedra, a cornercorner with one NiY3ZrNi12 tetrahedra, edges with six NiYZr2Ni9 cuboctahedra, and faces with eighteen NiYZr2Ni9 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.36–2.80 Å. In the fourth Ni site, Ni is bonded to three equivalent Y and nine Ni atoms to form distorted NiY3Ni9 cuboctahedra that share corners with eighteen NiYZr2Ni9 cuboctahedra, corners with three equivalent NiY3ZrNi12 tetrahedra, edges with six equivalent NiY3Ni9 cuboctahedra, faces with eighteen NiYZr2Ni9 cuboctahedra, and faces with three equivalent NiY3ZrNi12 tetrahedra. All Ni–Ni bond lengths are 2.81 Å. In the fifth Ni site, Ni is bonded to three equivalent Zr and nine Ni atoms to form distorted NiZr3Ni9 cuboctahedra that share corners with eighteen NiY2ZrNi9 cuboctahedra, edges with six equivalent NiZr3Ni9 cuboctahedra, faces with eighteen NiY2ZrNi9 cuboctahedra, and a faceface with one NiY3ZrNi12 tetrahedra. All Ni–Ni bond lengths are 2.79 Å. In the sixth Ni site, Ni is bonded to three equivalent Zr and nine Ni atoms to form distorted NiZr3Ni9 cuboctahedra that share corners with eighteen NiYZr2Ni9 cuboctahedra, edges with six equivalent NiZr3Ni9 cuboctahedra, faces with eighteen NiYZr2Ni9 cuboctahedra, and faces with three equivalent NiY3ZrNi12 tetrahedra. All Ni–Ni bond lengths are 2.80 Å. In the seventh Ni site, Ni is bonded in a 4-coordinate geometry to one Y, three equivalent Zr, and twelve Ni atoms. In the eighth Ni site, Ni is bonded in a 4-coordinate geometry to four Zr and twelve Ni atoms. In the ninth Ni site, Ni is bonded to three equivalent Y, one Zr, and twelve Ni atoms to form distorted NiY3ZrNi12 tetrahedra that share corners with twelve NiY2ZrNi9 cuboctahedra, faces with twenty-eight NiYZr2Ni9 cuboctahedra, and faces with six equivalent NiY3ZrNi12 tetrahedra.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on YSiBRh3 by Materials Project

YRh3BSi crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Y is bonded in a 12-coordinate geometry to twelve equivalent Rh, three equivalent B, and three equivalent Si atoms. All Y–Rh bond lengths are 3.24 Å. All Y–B bond lengths are 3.18 Å. All Y–Si bond lengths are 3.18 Å. Rh is bonded in a distorted rectangular see-saw-like geometry to four equivalent Y, two equivalent B, and two equivalent Si atoms. Both Rh–B bond lengths are 2.30 Å. Both Rh–Si bond lengths are 2.38 Å. B is bonded in a 9-coordinate geometry to three equivalent Y and six equivalent Rh atoms. Si is bonded in a 6-coordinate geometry to three equivalent Y and six equivalent Rh atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on CsY2CuTe4 by Materials Project

CsY2CuTe4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight Te2- atoms. There are a spread of Cs–Te bond distances ranging from 3.83–4.38 Å. In the second Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight Te2- atoms. There are a spread of Cs–Te bond distances ranging from 3.75–4.12 Å. In the third Cs1+ site, Cs1+ is bonded in a distorted q6 geometry to nine Te2- atoms. There are a spread of Cs–Te bond distances ranging from 4.07–4.23 Å. There are seven inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded to six Te2- atoms to form YTe6 octahedra that share corners with two equivalent YTe6 octahedra, corners with four equivalent CuTe4 tetrahedra, and edges with six YTe6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are two shorter (3.04 Å) and four longer (3.08 Å) Y–Te bond lengths. In the second Y3+ site, Y3+ is bonded to six Te2- atoms to form YTe6 octahedra that share corners with four equivalent YTe6 octahedra, edges with two equivalent YTe6 octahedra, and edges with four equivalent CuTe4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. All Y–Te bond lengths are 3.13 Å. In the third Y3+ site, Y3+ is bonded to six Te2- atoms to form YTe6 octahedra that share corners with four YTe6 octahedra, corners with two equivalent CuTe4 tetrahedra, edges with four YTe6 octahedra, edges with two equivalent CuTe4 tetrahedra, and a faceface with one CuTe4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–50°. There are a spread of Y–Te bond distances ranging from 3.09–3.14 Å. In the fourth Y3+ site, Y3+ is bonded to six Te2- atoms to form YTe6 octahedra that share a cornercorner with one YTe6 octahedra, corners with three CuTe4 tetrahedra, and edges with six YTe6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are a spread of Y–Te bond distances ranging from 3.03–3.14 Å. In the fifth Y3+ site, Y3+ is bonded to six Te2- atoms to form YTe6 octahedra that share corners with two equivalent YTe6 octahedra, corners with two equivalent CuTe4 tetrahedra, edges with six YTe6 octahedra, and a faceface with one CuTe4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Y–Te bond distances ranging from 3.06–3.16 Å. In the sixth Y3+ site, Y3+ is bonded to six Te2- atoms to form YTe6 octahedra that share corners with three YTe6 octahedra, corners with two equivalent CuTe4 tetrahedra, edges with four YTe6 octahedra, and edges with two equivalent CuTe4 tetrahedra. The corner-sharing octahedra tilt angles range from 5–49°. There are a spread of Y–Te bond distances ranging from 2.98–3.18 Å. In the seventh Y3+ site, Y3+ is bonded to six Te2- atoms to form YTe6 octahedra that share corners with three YTe6 octahedra, corners with two equivalent CuTe4 tetrahedra, edges with six YTe6 octahedra, and a faceface with one CuTe4 tetrahedra. The corner-sharing octahedra tilt angles range from 5–50°. There are a spread of Y–Te bond distances ranging from 2.99–3.26 Å. There are three inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four Te2- atoms to form CuTe4 tetrahedra that share corners with four YTe6 octahedra, corners with two equivalent CuTe4 tetrahedra, edges with two equivalent YTe6 octahedra, and a faceface with one YTe6 octahedra. The corner-sharing octahedra tilt angles range from 48–54°. There are a spread of Cu–Te bond distances ranging from 2.56–2.81 Å. In the second Cu1+ site, Cu1+ is bonded to four Te2- atoms to form CuTe4 tetrahedra that share corners with four YTe6 octahedra, corners with two equivalent CuTe4 tetrahedra, edges with two equivalent YTe6 octahedra, and a faceface with one YTe6 octahedra. The corner-sharing octahedra tilt angles range from 47–54°. There are a spread of Cu–Te bond distances ranging from 2.57–2.78 Å. In the third Cu1+ site, Cu1+ is bonded to four Te2- atoms to form CuTe4 tetrahedra that share corners with five YTe6 octahedra, corners with two equivalent CuTe4 tetrahedra, edges with two equivalent YTe6 octahedra, and a faceface with one YTe6 octahedra. The corner-sharing octahedra tilt angles range from 19–54°. There are a spread of Cu–Te bond distances ranging from 2.57–2.79 Å. There are twelve inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 6-coordinate geometry to one Cs1+, three Y3+, and two equivalent Cu1+ atoms. In the second Te2- site, Te2- is bonded in a 7-coordinate geometry to four Cs1+, two equivalent Y3+, and one Cu1+ atom. In the third Te2- site, Te2- is bonded in a 4-coordinate geometry to two equivalent Cs1+, three Y3+, and one Cu1+ atom. In the fourth Te2- site, Te2- is bonded in a 6-coordinate geometry to one Cs1+, three Y3+, and two equivalent Cu1+ atoms. In the fifth Te2- site, Te2- is bonded in a 7-coordinate geometry to four Cs1+, two equivalent Y3+, and one Cu1+ atom. In the sixth Te2- site, Te2- is bonded in a 4-coordinate geometry to two equivalent Cs1+, three Y3+, and one Cu1+ atom. In the seventh Te2- site, Te2- is bonded in a 7-coordinate geometry to two equivalent Cs1+, three Y3+, and two equivalent Cu1+ atoms. In the eighth Te2- site, Te2- is bonded in a 6-coordinate geometry to two equivalent Cs1+, three Y3+, and one Cu1+ atom. In the ninth Te2- site, Te2- is bonded in a 4-coordinate geometry to two equivalent Cs1+, three Y3+, and one Cu1+ atom. In the tenth Te2- site, Te2- is bonded to one Cs1+ and four Y3+ atoms to form distorted TeCsY4 trigonal bipyramids that share corners with three equivalent TeCsY4 trigonal bipyramids and edges with two equivalent TeCs3Y3 octahedra. In the eleventh Te2- site, Te2- is bonded to three equivalent Cs1+ and three Y3+ atoms to form distorted TeCs3Y3 octahedra that share edges with four equivalent TeCs3Y3 octahedra and edges with two equivalent TeCsY4 trigonal bipyramids. In the twelfth Te2- site, Te2- is bonded to one Cs1+ and four Y3+ atoms to form a mixture of corner and edge-sharing TeCsY4 trigonal bipyramids.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on CaYMg6 by Materials Project

CaMg6Y is beta Cu3Ti-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ca is bonded to twelve Mg atoms to form CaMg12 cuboctahedra that share corners with four equivalent CaMg12 cuboctahedra, corners with eight equivalent YMg12 cuboctahedra, edges with twenty-four MgCa2Y2Mg8 cuboctahedra, faces with two equivalent CaMg12 cuboctahedra, faces with four equivalent YMg12 cuboctahedra, and faces with twelve MgCa2Y2Mg8 cuboctahedra. There are eight shorter (3.36 Å) and four longer (3.37 Å) Ca–Mg bond lengths. There are three inequivalent Mg sites. In the first Mg site, Mg is bonded to two equivalent Ca, eight Mg, and two equivalent Y atoms to form MgCa2Y2Mg8 cuboctahedra that share corners with twelve equivalent MgCa2Y2Mg8 cuboctahedra, edges with four equivalent CaMg12 cuboctahedra, edges with four equivalent YMg12 cuboctahedra, edges with sixteen MgCa2Y2Mg8 cuboctahedra, faces with two equivalent CaMg12 cuboctahedra, faces with two equivalent YMg12 cuboctahedra, and faces with fourteen MgCa2Y2Mg8 cuboctahedra. All Mg–Mg bond lengths are 3.32 Å. Both Mg–Y bond lengths are 3.37 Å. In the second Mg site, Mg is bonded to two equivalent Ca, eight Mg, and two equivalent Y atoms to form distorted MgCa2Y2Mg8 cuboctahedra that share corners with twelve equivalent MgCa2Y2Mg8 cuboctahedra, edges with four equivalent CaMg12 cuboctahedra, edges with four equivalent YMg12 cuboctahedra, edges with sixteen MgCa2Y2Mg8 cuboctahedra, faces with two equivalent CaMg12 cuboctahedra, faces with two equivalent YMg12 cuboctahedra, and faces with fourteen MgCa2Y2Mg8 cuboctahedra. There are two shorter (3.29 Å) and two longer (3.45 Å) Mg–Mg bond lengths. Both Mg–Y bond lengths are 3.28 Å. In the third Mg site, Mg is bonded to two equivalent Ca, eight Mg, and two equivalent Y atoms to form distorted MgCa2Y2Mg8 cuboctahedra that share corners with twelve equivalent MgCa2Y2Mg8 cuboctahedra, edges with four equivalent CaMg12 cuboctahedra, edges with four equivalent YMg12 cuboctahedra, edges with sixteen MgCa2Y2Mg8 cuboctahedra, faces with two equivalent CaMg12 cuboctahedra, faces with two equivalent YMg12 cuboctahedra, and faces with fourteen MgCa2Y2Mg8 cuboctahedra. Both Mg–Y bond lengths are 3.28 Å. Y is bonded to twelve Mg atoms to form YMg12 cuboctahedra that share corners with four equivalent YMg12 cuboctahedra, corners with eight equivalent CaMg12 cuboctahedra, edges with twenty-four MgCa2Y2Mg8 cuboctahedra, faces with two equivalent YMg12 cuboctahedra, faces with four equivalent CaMg12 cuboctahedra, and faces with twelve MgCa2Y2Mg8 cuboctahedra.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on CaYMg30O32 by Materials Project

CaMg30YO32 is alpha Po-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ca is bonded to six O atoms to form CaO6 octahedra that share corners with six MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.26 Å) and two longer (2.27 Å) Ca–O bond lengths. There are eight inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with two equivalent MgO6 octahedra, corners with two equivalent YO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.07–2.19 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.06 Å) and four longer (2.18 Å) Mg–O bond lengths. In the third Mg site, Mg is bonded to six O atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.14 Å) and two longer (2.16 Å) Mg–O bond lengths. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent YO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.09 Å) and four longer (2.17 Å) Mg–O bond lengths. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one CaO6 octahedra, an edgeedge with one YO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Mg–O bond distances ranging from 2.14–2.19 Å. In the sixth Mg site, Mg is bonded to six O atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are two shorter (2.16 Å) and four longer (2.17 Å) Mg–O bond lengths. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one CaO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.13–2.20 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one YO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Mg–O bond distances ranging from 2.11–2.22 Å. Y is bonded to six O atoms to form YO6 octahedra that share corners with six MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.23 Å) and two longer (2.24 Å) Y–O bond lengths. There are thirteen inequivalent O sites. In the first O site, O is bonded to one Ca and five Mg atoms to form OCaMg5 octahedra that share corners with six OCaMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OCaMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the third O site, O is bonded to five Mg and one Y atom to form a mixture of corner and edge-sharing OYMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 1–5°. In the fifth O site, O is bonded to one Ca and five Mg atoms to form a mixture of corner and edge-sharing OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the sixth O site, O is bonded to one Ca and five Mg atoms to form a mixture of corner and edge-sharing OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are two shorter (2.14 Å) and two longer (2.20 Å) O–Mg bond lengths. In the seventh O site, O is bonded to five Mg and one Y atom to form OYMg5 octahedra that share corners with six OCaMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. The O–Mg bond length is 2.10 Å. In the eighth O site, O is bonded to five Mg and one Y atom to form OYMg5 octahedra that share corners with six OCaMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of O–Mg bond distances ranging from 2.10–2.22 Å. In the ninth O site, O is bonded to six Mg atoms to form a mixture of corner and edge-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the tenth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OYMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the eleventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OYMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. Both O–Mg bond lengths are 2.11 Å. In the twelfth O site, O is bonded to five Mg and one Y atom to form OYMg5 octahedra that share corners with six OCaMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. Both O–Mg bond lengths are 2.22 Å. In the thirteenth O site, O is bonded to five Mg and one Y atom to form OYMg5 octahedra that share corners with six OCaMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are two shorter (2.19 Å) and two longer (2.22 Å) O–Mg bond lengths.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on CaYMg14O16 by Materials Project

CaMg14YO16 is alpha Po-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ca is bonded to six O atoms to form CaO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.21 Å) and four longer (2.29 Å) Ca–O bond lengths. There are five inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with two equivalent MgO6 octahedra, corners with two equivalent YO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.09–2.21 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CaO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.16–2.23 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CaO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.16–2.23 Å. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent YO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Mg–O bond distances ranging from 2.08–2.30 Å. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, an edgeedge with one CaO6 octahedra, an edgeedge with one YO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Mg–O bond distances ranging from 2.16–2.23 Å. Y is bonded to six O atoms to form YO6 octahedra that share corners with two equivalent YO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.21 Å) and four longer (2.26 Å) Y–O bond lengths. There are ten inequivalent O sites. In the first O site, O is bonded to one Ca and five Mg atoms to form a mixture of edge and corner-sharing OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the second O site, O is bonded to five Mg and one Y atom to form a mixture of edge and corner-sharing OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. Both O–Mg bond lengths are 2.21 Å. In the third O site, O is bonded to five Mg and one Y atom to form a mixture of edge and corner-sharing OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are two shorter (2.21 Å) and two longer (2.23 Å) O–Mg bond lengths. In the fourth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 2–5°. In the fifth O site, O is bonded to two equivalent Ca and four Mg atoms to form OCa2Mg4 octahedra that share corners with six OCa2Mg4 octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the sixth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OCa2Mg4 octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O site, O is bonded to four equivalent Mg and two equivalent Y atoms to form OY2Mg4 octahedra that share corners with six OMg6 octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the eighth O site, O is bonded to one Ca and five Mg atoms to form a mixture of edge and corner-sharing OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. Both O–Mg bond lengths are 2.16 Å. In the ninth O site, O is bonded to five Mg and one Y atom to form a mixture of edge and corner-sharing OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. The O–Mg bond length is 2.12 Å. In the tenth O site, O is bonded to five Mg and one Y atom to form a mixture of edge and corner-sharing OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of O–Mg bond distances ranging from 2.12–2.23 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2025

Search for e + e − → φ χ c 0 and φ η c 2 ( 1 D ) at center-of-mass energies from 4.47 to 4.95 GeV

Utilizing a dataset of 6.7 fb − 1 from electron-positron collisions recorded by the BESIII detector at the BEPCII storage ring, a search is conducted for the processes e + e − → ϕ χ c 0 and ϕ η c 2 ( 1 D ) across center-of-mass energies from 4.47 to 4.95 GeV. In the absence of any significant signals, upper limits are set. These include limits on the dressed cross sections for e + e − → ϕ χ c 0 , as well as the product of the dressed cross section for e + e − → ϕ η c 2 ( 1 D ) and a sum of five branching fractions. Furthermore, the product of the electronic width of Y ( 4660 ) and the branching fraction of the Y ( 4660 ) → ϕ χ c 0 , denoted as Γ e + e − Y ( 4660 ) B Y ( 4660 ) → ϕ χ c 0 , is determined to be < 0.35 eV at the 90% confidence level. Published by the American Physical Society 2025

Ablikim, M.↗

DOE OSTI2023

Gravity-improved metastability bounds for the Type-I seesaw mechanism

Right-handed neutrinos (RHN) destabilize the electroweak vacuum by increasing its decay rate. In the SM, the latter is dominated by physics at the RG scale at which λ reaches its minimum, ${\mu}_{\ast}^{\textrm{SM}}$ ~10 17 GeV. For large neutrino Yukawa coupling Y ν , RHNs can push μ* beyond the Planck scale, implying that gravitational effects need to be taken into account. In this work, we perform the first comprehensive study of electroweak vacuum metastability in the type-I seesaw mechanism including these effects. Our analysis covers both low- and high-scale seesaw models, with two as well as three RHNs and for multiple values of the Higgs’ non-minimal coupling to gravity. We find that gravitational effects can significantly stabilize the vacuum, leading to weaker metastability bounds. We show that metastability sets the strongest bounds for low-scale seesaws with M N > 1 TeV. For high-scale seesaws, we find upper bounds on the allowed masses for the RHNs, which are relevant for high-scale leptogenesis. We also point out that Tr(${Y}_{\nu}^{\dagger}$Y ν ), which is commonly used to express these metastability bounds, cannot be used for all of parameter space. Instead, we argue that bounds can always be expressed reliably through Tr(${Y}_{\nu}^{\dagger}$Y ν ${Y}_{\nu}^{\dagger}$Y ν ). Lastly, we use this insight to develop a new technique for an easier RG analysis applicable to scenarios with degenerate RHN masses.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2026

The solubility and speciation of REE phosphate endmembers (CePO 4 and YPO 4 ) in Cl-rich aqueous fluids from 350 to 450 °C and implications for natural systems

The rare earth elements (REE) are important metals used increasingly in advanced technologies. Within the crust, the elements Ce and Y are commonly more abundant compared to other lanthanides and comprise important end-member constituents of REE-bearing minerals. Specifically, Ce is part of the light (L) REE which have larger ionic radii than the heavy (H) REE, which are grouped together with Y. These differences in ionic radius can lead to important physico-chemical trends within the lanthanide group. Despite a recent increase in experimental and thermodynamic data for the REE at high temperature and pressure, there is still a significant lack of these data at supercritical conditions. In this study we conducted batch-type experiments to measure the solubility of REE phosphates (CePO 4 and YPO 4 ) at varying starting pH (1.5–10), and salinity (0.01–1.4 mol/kg NaCl) at 350 and P sat , and from 400 to 450 °C at 700 bar. Results show that the solubility of Ce (33–0.14 ppb) is generally higher than Y (13–0.13 ppb) and that Ce complexes more strongly with both chloride and hydroxyl ligands compared to Y. The solubilities of both REE phosphates are highly pH-dependent and, to a lesser extent, depend on salinity at the studied conditions. The solubility data from this study were implemented into the GEMSFITS program to optimize the thermodynamic properties of Ce and Y hydroxyl and chloride species. The updated standard partial molal Gibbs energies of formation (Δ f G 0 T,P ) are used within the experimental temperature and pressure range to accurately predict the CePO 4 and YPO 4 solubility and Ce and Y speciation behavior. Based on the updated thermodynamic properties we also provide formation constants (log β n Cl,OH ) for Ce and Y hydroxyl and chloride species. Updated thermodynamic properties are applied to model REE-apatite dissolution and REE mobility based on the Pea Ridge iron oxide apatite deposit in Missouri, USA. The apatite dissolution model replicates natural observations including the replacement of monazite and xenotime after apatite and is an example of the utility of the new thermodynamic constants applied to supercritical crustal fluids. Furthermore, the findings of this study advance the predictive capabilities of geochemical models, our understanding of the behavior of individual REE, and permit modeling the overarching fractionation trends between LREE and HREE in supercritical crustal fluids.

58 GEOSCIENCES↗

DOE OSTI2021

Property enhancement of CoCrNi medium-entropy alloy by introducing nano-scale features

CoCrNi -medium-entropy alloy (MEA) has been widely investigated due to its superior mechanical properties that overcome strength-ductility tradeoff. Here we show further property enhancement of CoCrNi MEA by introducing nano-scale features. Both CoCrNi and oxide dispersion strengthened (ODS) CoCrNi are fabricated by mechanical alloying and spark plasma sintering. Microstructural characterization and mechanical testing of these nanostructured MEAs revealed that the nano-scale features significantly improves the strength of the alloys. In ODS-CoCrNi MEA, Y 2 Ti 2 O 7 oxides with an average diameter of 7.3 ± 3.2 nm are incoherent with the matrix, and a specific orientation relationship exists between Y 2 Ti 2 O 7 and the matrix, which is [011] Y 2 Ti 2 O 7 //[011]Matrix, (400) Y 2 Ti 2 O 7 //(200)Matrix and ($22\bar2$) Y 2 Ti 2 O 7 //($11\bar1$)Matrix. The recrystallization and grain growth processes are effectively suppressed by the introduction of Y 2 Ti 2 O 7 nanoparticles. Strengthening mechanism analyses indicate that the strength improvement of ODS-CoCrNi is mainly ascribed to the precipitation strengthening of Y 2 Ti 2 O 7 .

36 MATERIALS SCIENCE↗

DOE OSTI2023

Tuning the Radius Ratio to Enhance Thermoelectric Properties in the Zintl Compounds AM 2 Sb 2 (A = Ba, Sr; M = Zn, Cd)

Five novel Zintl phase solid solutions in the Ba 1–x Sr x Zn 2–y Cd y Sb 2 (0 ≤ x ≤ 0.13(1); 0 ≤ y ≤ 0.32(2)) system were successfully synthesized by the molten Pb metal-flux method, and the powder X-ray diffraction and single-crystal X-ray diffraction analyses proved that all five title compounds adopted the BaCu 2 S 2 -type phase having the orthorhombic Pnma space group (Z = 4, Pearson code oP20) with five crystallographically independent atomic sites. The previously studied BaCu 2 S 2 -type antimonides demonstrated a limited tolerance for doping in contrast to the CaAl 2 Si 2 -type antimonides. To understand the relatively narrower phase width and limited dopability of the title BaCu 2 S 2 -type phase than the CaAl 2 Si 2 -type phase in the overall Ba 1–x Sr x Zn 2–y Cd y Sb 2 system, the radius ratio of cations and anionic elements r + /r – for two structure types were thoroughly investigated. For the first time, the r + /r – ratio was identified as a critical factor for the phase selectivity: (1) r + /r – > 1 favored the BaCu 2 S 2 -type phase, and (2) r + /r – < 1 favored the CaAl 2 Si 2 -type phase. Further, we also revealed the structural transformation mechanism from the more widely observed CaAl 2 Si 2 -type phase to the title BaCu 2 S 2 -type phase as the relatively larger cationic elements were introduced to the system. A series of DFT calculations using the three hypothetical models indicated that a resonance peak near EF in the density of states curves was descended from the relatively flat band structure at several special symmetry points rationalizing the enhanced Seebeck coefficients of Ba 0.94(1) Sr 0.06 Zn 1.86(3) Cd 0.14 Sb 2 and Ba 0.96(1) Sr 0.04 Zn 1.68(2) Cd 0.32 Sb 2 . Electron localization function analysis rationalized the correlation between the polarity change of anionic Zn/Cd–Sb bonds and the charge carrier mobility on the anionic frameworks. Temperature-dependent thermoelectric properties were studied for the four title compounds, and the results proved that the Sr and Cd doping in the title Ba 1–x Sr x Zn 2–y Cd y Sb 2 system successfully enhanced the ZT values through the increased Seebeck coefficients and the reduced total thermal conductivities.

36 MATERIALS SCIENCE↗

DOE OSTI2025

Effect of Sulfonation Level on the Percolated Morphology and Proton Conductivity of Hydrated Fluorine-Free Copolymers: Experiments and Simulations

Using all-atom molecular dynamics simulations and a variety of experimental methods, we previously reported on a linear polyethylene with pendant phenyl sulfonated groups precisely on every fifth carbon along the backbone. With increasing relative humidity this fluorine-free polymer self-assembled to form nanoscale water channels and exhibited exceptional proton conductivity. Expanding upon those findings, here we explore partially sulfonated random copolymers, referred to as p 5PhSH-Y. Using either acetyl sulfate or sulfuric acid, a wide range of sulfonation levels were prepared ( Y = 34−98%) corresponding to ion-exchange capacities (IEC) of 2.0−4.4 mmol/g. Combining experimental techniques and all-atom molecular dynamics simulations, we study the effect of Y on water uptake, nanoscale morphology, and the proton/water transport properties of p5PhSH- Y . The proton conductivity of p 5PhSH- Y increases with relative humidity and with Y and achieves values in excess of 0.1 S/cm. These high conductivities are attributed to high IEC and welldeveloped nanoscale percolated hydrophilic domains made possible by the flexible backbone. We quantitatively describe the nature of the water channels using the characteristic distance, channel width distribution, the area per sulfonate group at the hydrophilic/ hydrophobic interface, and the fractal dimension. Notably, the channel widths and the areas per sulfonate group are nominally independent of the level of sulfonation, while depending significantly on the level of hydration. The fractal dimension of the water channels correlates strongly with the water diffusion coefficients calculated from the molecular dynamics (MD) simulations. These findings demonstrate that the p 5PhSH- Y hydrocarbon copolymers can be modified to tune properties, particularly proton conductivity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Electrocatalytic nitrate reduction on rhodium sulfide compared to Pt and Rh in the presence of chloride

Chloride poisoning is a serious problem for the electrocatalytic reduction of aqueous nitrate (NO 3 – ) and improved electrocatalysts are needed. Here we study the electrocatalytic activity of rhodium sulfide supported on carbon (Rh x S y /C) for the reduction of nitrate and compare it against Pt/C and Rh/C in the presence of chloride. Between 0.05–0.15 V vs. RHE, Rh x S y /C has a steady-state nitrate reduction current density in 1 M H 2 SO 4 + 1 M NaNO 3 that is 1.6–5.6 times greater than Rh/C (the most active metal electrocatalyst) and 10–24 times greater than Pt/C. Current densities are decreased by 37% for Rh x S y /C, 62% for Rh/C, and 40% for Pt/C at 0.1 V vs. RHE in the presence of 1 mM chloride. The decrease in nitrate reduction activity for Pt, Rh, and Rh x S y is due to the competitive adsorption of chloride and nitrate on the surface. Density functional theory (DFT) modeling predicts that chloride poisoning will persistently inhibit nitrate reduction on metals due to linear adsorbate scaling relations between nitrate and chloride. DFT calculations and microkinetic modeling of our experimental measurements predict that nitrate converts to nitrite via an H-assisted dissociation mechanism on Pt and direct nitrate dissociation on Rh and Rh x S y . Pristine Rh x S y (i.e., Rh 3 S 4 , Rh 2 S 3 , and Rh 17 S 15 ) terraces are predicted to be inactive toward nitrate reduction. In contrast, sulfur vacancies in Rh 3 S 4 terraces are predicted to be active for nitrate reduction, but also bind chloride strongly. Furthermore, sulfur-defected Rh 3 S 4 rationalize the experimentally observed high activity but moderate chloride poison-resistance of Rh x S y /C for nitrate reduction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Novel usage of deep learning and high-performance computing in long-baseline neutrino oscillation experiments

Mención Internacional en el título de doctorDeep-learning methods are playing a crucial role in numerous scientific and industrialapplications. Over the past two decades, these techniques have helped in the collection,reconstruction, and analysis of large data samples in particle physics experiments. Themain topic of this PhD research is the study of deep-learning techniques in long-baselineneutrino oscillation experiments. Neutrinos are mysterious light elementary particles,and their investigation is essential to shed light on some of the remaining open questionsin physics. The work presented here describes an algorithm based on a convolutionalneural network developed to provide highly accurate and efficient selections of electronneutrino and muon neutrino interactions in the Deep Underground Neutrino Experiment(DUNE). With this algorithm, the electron neutrino (antineutrino) selection efficiencypeaks at 90% (94%) and exceeds 85% (90%) for reconstructed neutrino energies between2-5 GeV. The selection efficiency for muon neutrino (antineutrino) interactions is foundto have a maximum of 96% (97%) and exceeds 90% (95%) efficiency for reconstructedneutrino energies above 2 GeV. When considering all electron neutrino and antineutrinointeractions as signal (both those appearing from oscillations and those intrinsic tothe beam), a selection purity of 90% is achieved. These event selections are criticalto maximise the sensitivity of the experiment to CP-violating effects, key to furtherunderstand the matter-antimatter asymmetry of the Universe.In high-energy physics experiments, deep learning has also been explored for producingfast simulations and physically-motivated manipulations of simulated images. Some ofthose simulations, such as the light production and detection, are very computationallyexpensive and require novel methods to produce the necessary samples while controllingthe varied underlying physics model parameters. To do so, we invented the model-assistedgenerative adversarial network (MAGAN), first validated on simple generic case studiesand then successfully applied to the DUNE photon-detector simulation.Moreover, we also developed graph neural networks for 3D-voxel classification ofambiguities and optical crosstalk for a different particle physics experiment, most preciselyfor the proposed SuperFGD. This novel 3D-granular plastic-scintillator neutrino detectorwill be used to upgrade the near detector of the T2K neutrino oscillation experiment, and our method reports efficiencies and purities of 94-96% per event in the classificationof particle track voxels.Due to the growth and complexity of deep neural networks, researchers have beeninvestigating techniques to train those networks in a more computationally-efficient way.Many efforts have been made by the community to optimise deep-learning models byparallelising or distributing their training computation across multiple devices. In thisthesis, we study an approach based on data locality for those neural networks that cannotbenefit from scaling their computation due to a significant bottleneck in the data I/O.The research also includes a detailed study on the performance of deep neural networkson hardware accelerator boards.Los métodos de aprendizaje profundo son cada vez más utilizados en numerosas aplicacionescientíficas e industriales hoy en día. Durante las dos últimas décadas, estastécnicas se han empleado en la recolección, reconstrucción y análisis de la gran cantidadde datos generados por experimentos de física de partículas. El tema principal de estatesis doctoral es el uso de estos modelos de aprendizaje profundo en experimentos defísica de neutrinos, en concreto en los experimentos de larga distancia DUNE y T2K. Losneutrinos, partículas fundamentales neutras, de las más ligeras del Universo, pueden serclave para explicar algunas de las cuestiones todavía sin resolver en física fundamental.Entre las diferentes contribuciones que esta tesis ha hecho a su estudio, cabe destacar eldesarrollo de un algoritmo basado en una red de neuronas convolucional para seleccionarcon gran eficiencia y precisión las interacciones de neutrinos electrónicos y muónicos enel Deep Underground Neutrino Experiment (DUNE). La eficiencia de selección obtenidapara neutrinos (antineutrinos) electrónicos alcanza un máximo del 90% (94%) y supera el85% (90%) para neutrinos con energías reconstruidas en el rango 2-5 GeV. La selección deneutrinos (antineutrinos) muónicos tiene una eficiencia máxima del 96% (97%) y excedeel 90% (95%) para neutrinos con energías reconstruidas de más de 2 GeV. Considerandocomo señal todas las interacciones de neutrinos y antineutrinos electrónicos (procedentestanto de oscilaciones como intrínsecos en el haz inicial), se logra una pureza en la seleccióndel 90%. Dichas selecciones de eventos son fundamentales para maximizar la sensibilidaddel experimento a los efectos de violació...

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2020

The striking influence of oxophilicity differences in heterometallic Mo–Mn oxide cluster reactions with water

Mixed-metal oxides have proven to be effective catalysts for the hydrogen evolution reaction, often outperforming either of the binary metal oxides. The reactivity of Mn x MoO y - (x = 1, 2; y = 3, 4) clusters toward H 2 O was investigated via time-of-flight mass spectrometry with clear evidence of cluster oxidation and corresponding H 2 production, specifically for Mn x MoO 3 - (x = 1, 2) clusters. Unlike previously studied MoxOy- clusters, which assumed a broad distribution of stoichiometries (typically x ≤ y ≤ 3x), both MnMoOy- and Mn 2 MoO y - preferentially formed y = 3 and 4 compositions in significant quantities under our source conditions. The electronic and molecular structures of the Mn x MoO y (x = 1, 2; y = 3, 4) anion and neutral clusters were probed with anion photoelectron spectroscopy and analyzed with supporting density functional theory calculations. Our studies suggest that both metal centers are involved in initial cluster–water complex formation, while Mo is the center that undergoes oxidation; hence, reactivity terminates when Mo is saturated in its highest oxidation state of +6. Across these four clusters, Mn remains relatively reduced and is stable in a high-spin electronic configuration. The preferential reactivity of water molecules toward the Mo center rather than Mn is rationalized by the much lower relative oxophilicity of Mn.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Metabolic engineering of the oleaginous yeast Yarrowia lipolytica PO1f for production of erythritol from glycerol

Abstract Background Sugar alcohols are widely used as low-calorie sweeteners in the food and pharmaceutical industries. They can also be transformed into platform chemicals. Yarrowia lipolytica , an oleaginous yeast, is a promising host for producing many sugar alcohols. In this work, we tested whether heterologous expression of a recently identified sugar alcohol phosphatase (PYP) from Saccharomyces cerevisiae would increase sugar alcohol production in Y. lipolytica . Results Y. lipolytica was found natively to produce erythritol, mannitol, and arabitol during growth on glucose, fructose, mannose, and glycerol. Osmotic stress is known to increase sugar alcohol production, and was found to significantly increase erythritol production during growth on glycerol. To better understand erythritol production from glycerol, since it was the most promising sugar alcohol, we measured the expression of key genes and intracellular metabolites. Osmotic stress increased the expression of several key genes in the glycerol catabolic pathway and the pentose phosphate pathway. Analysis of intracellular metabolites revealed that amino acids, sugar alcohols, and polyamines are produced at higher levels in response to osmotic stress. Heterologous overexpression of the sugar alcohol phosphatase increased erythritol production and glycerol utilization in Y. lipolytica . We further increased erythritol production by increasing the expression of native glycerol kinase (GK), and transketolase (TKL). This strain was able to produce 27.5 ± 0.7 g/L erythritol from glycerol during batch growth and 58.8 ± 1.68 g/L erythritol during fed-batch growth in shake-flasks experiments. In addition, the glycerol utilization was increased by 2.5-fold. We were also able to demonstrate that this strain efficiently produces erythritol from crude glycerol, a major byproduct of the biodiesel production. Conclusions We demonstrated the application of a promising enzyme for increasing erythritol production in Y. lipolytica . We were further able to boost production by combining the expression of this enzyme with other approaches known to increase erythritol production in Y. lipolytica . This suggest that this new enzyme provides an orthogonal route for boosting production and can be stacked with existing designs known to increase sugar alcohol production in yeast such as Y. lipolytica . Collectively, this work establishes a new route for increasing sugar alcohol production and further develops Y. lipolytica as a promising host for erythritol production from cheap substrates such as glycerol.

09 BIOMASS FUELS↗

DOE OSTI2024

Magnetic properties of Lutetium and Yttrium doped Ce 2 Fe 14 B magnets

The increasing demand for Nd-Dy and Sm-Co based permanent magnets is exacerbating the current critical materials shortage, therefore improving and optimizing current candidate critical element free permanent magnets is necessary to develop future clean energy technologies. In this work, we aim to increase the thermal stability and magnetic performance of Ce 2 Fe 14 B based permanent magnets through the substitution of Ce ions with noncritical rare earth elements Lu and Y. The substitution of Lu (x=0; 0.05; 0.1; 0.15) for Ce ions in (LuxCe 2-x )Fe 14 B was unsuccessful, likely due to disparities in ionic size and valencies, and failed to exhibit improved thermal stability or magnetic performance. In contrast, Y substitution for Ce ions in (Y x Ce 2-x )Fe14B (x= 0.1; 0.2; 0.3; 0.4; 0.5) alloys was successful. Notably, these alloys demonstrated enhanced thermal stability, as evidenced by an increase in the Curie temperature, reaching a peak of 443 K at x= 0.5. Y substitution also helped to suppress the CeFe2 Laves phase. Without loss of the anisotropy field Y substitution increased the saturation magnetization, MS, peaking at MS = 125 emu/g for a Y concentration of x= 0:4, demonstrating (Y 0.4 Ce 1.6 )Fe 14 B as a potential critical element free permanent magnet with an energy product as high as 29 MGOe. This work is advantageous in developing low cost high performance permanent magnets with reduced or little to no critical rare earth elements.

Rai, Binod K.↗

DOE OSTI2022

Removable, Sequestration Coatings for Mitigating Hazardous Contaminants Related to Deactivation and Decommissioning Activities

This project is a collaborative effort between InnoSense LLC (ISL) and Oak Ridge National Laboratory (ORNL) aimed at mitigating the mercury (Hg) contamination problem at the Y-12 National Security Complex (NSC). The report summarizes the research and technology development work of the Phase IIB Project, led by Dr. Uma Sampathkumaran at ISL for the period of July 31, 2017–October 31, 2021. The Y-12 site cleanup includes technologies for safe and cost-effective facility demolition, soil remediation, and on-site treatment and disposal of mercury bearing wastes. One of the technology demonstration goals was a reactive strippable coating for targeted pre-demolition and de-contamination to limit Hg mobilization and the volume of debris requiring treatment for disposal. Toward this, ISL has developed a water-based reactive strippable coating (Trap & See-Hg™) to sequester elemental Hg(0) and mercuric Hg(II) species in the coating. The coating provides multiple benefits including (1) Hg vapor suppression, (2) sealing in the hazardous contaminants, (3) visually locating the contaminant through color changes, and (4) remediating the contaminated surfaces upon coating removal. Through collaboration between ORNL and ISL in Phase II work, the team successfully demonstrated the Trap & See-Hg technology to (1) visually locate the presence of Hg on concrete, soil and drywall surfaces, (2) effectively sequester all mercury species (elemental, soluble and insoluble Hg) from lab-generated and ex-situ soil and brick/rubble samples collected from the Y 12 site with 80 to 95% efficiency to capture/reduce Hg vapor concentration, (3) be applied by manual and robotic spray applicators and cure at room ambient, (4) remain a cohesive and peelable coating upon drying, and (5) sequester Hg0 from walls in the alpha-2 building basement at Y-12 during a small scale in-situ field trial. In Phase IIB, ISL’s effort was focused on refining the coating formulations with additives containing passive and reactive sorbents, colorimetric indicator, and thixotropic agents to achieve the desired performance. The paints were then evaluated at ORNL for applicability to metal and concrete surfaces of different sizes and shapes, and soil rubble, Hg-sorption capacity and achieving sag-free coating on surfaces when applied by a manual spray applicator. Ambient cure of the coating resulted in a dry thickness of 16–20 mil. The coatings were removed from smooth or rough surfaces with low to moderate force. Both lab-generated Hg-contaminated samples and soil and brick/rubble samples containing a range of Hg concentrations (collected from the Y-12 site by UCOR) were used in this project. Optimized formulations were applied to these samples and evaluated for ability to suppress Hg vapors, sequester Hg 0 and Hg(II) species and color mapping of mercury species on the test surface. The ORNL team initially identified three to four potential sites at Y-12 and ORNL for potential demonstration. However, the pandemic closed any possible avenues for on-site demonstration of the robotic spray applicator. The metal and concrete samples with low to high Hg content provided by UCOR from an ongoing demolition were subsequently used for ex-situ sample characterization and analysis at ORNL over a period of 25 days. The coatings suppressed Hg vapors with an efficiency of 95–99% from heavily contaminated metal and 60% from concrete substrate. Analysis of total Hg in the peeled paints indicates sorption capacities ranging from 12 µg Hg/g of paint from concrete to 1.2 mg Hg/g of paint from the metal substrates while peeled paints from soil samples could capture a total Hg from 2.3 mg Hg/g to 66 mg/g paint. Toxicity characteristic leaching procedure (TCLP) tests recovered total mercury leached at 0.15±0.0008 µg/L for concrete to 126.81±0.67 µg/L and 377.25±5.67 µg/L for the two metal substrates, to allow for informed decisions on downstream disposal considerations. Together, this Phase IIB demonstrated the potential value of the Trap & See-Hg for Hg uptake, vapor suppression, and color mapping, and may thus be used to enhance worker safety during site cleanup, facility demolition, and downstream waste disposal at Y-12 NSC.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗