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DOE OSTI2020

Materials Data on Zn(CoO2)2 by Materials Project

ZnCo2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are twelve inequivalent Co3+ sites. In the first Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three CoO4 tetrahedra, corners with three ZnO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.92–1.97 Å. In the second Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent CoO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.91–1.97 Å. In the third Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with six CoO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 53–61°. There are a spread of Co–O bond distances ranging from 1.87–1.93 Å. In the fourth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four CoO4 tetrahedra, edges with three CoO6 octahedra, and edges with three ZnO6 octahedra. There are a spread of Co–O bond distances ranging from 1.90–1.98 Å. In the fifth Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine CoO6 octahedra. The corner-sharing octahedra tilt angles range from 57–63°. There are a spread of Co–O bond distances ranging from 1.94–2.01 Å. In the sixth Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with six CoO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 53–62°. There is two shorter (1.87 Å) and two longer (1.92 Å) Co–O bond length. In the seventh Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six CoO4 tetrahedra, edges with two equivalent CoO6 octahedra, and edges with four ZnO6 octahedra. There are a spread of Co–O bond distances ranging from 1.91–1.96 Å. In the eighth Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with six CoO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 53–61°. There are a spread of Co–O bond distances ranging from 1.87–1.93 Å. In the ninth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one ZnO4 tetrahedra, corners with five CoO4 tetrahedra, edges with three CoO6 octahedra, and edges with three ZnO6 octahedra. There are a spread of Co–O bond distances ranging from 1.91–1.98 Å. In the tenth Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with six CoO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 53–61°. There are a spread of Co–O bond distances ranging from 1.87–1.94 Å. In the eleventh Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent CoO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.91–1.97 Å. In the twelfth Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine CoO6 octahedra. The corner-sharing octahedra tilt angles range from 57–63°. There is three shorter (1.95 Å) and one longer (2.03 Å) Co–O bond length. There are eight inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine CoO6 octahedra. The corner-sharing octahedra tilt angles range from 57–63°. There are three shorter (1.96 Å) and one longer (2.04 Å) Zn–O bond lengths. In the second Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with three CoO4 tetrahedra, corners with three ZnO4 tetrahedra, and edges with six CoO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.05–2.07 Å. In the third Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine CoO6 octahedra. The corner-sharing octahedra tilt angles range from 58–63°. There are a spread of Zn–O bond distances ranging from 1.96–2.05 Å. In the fourth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four CoO4 tetrahedra, an edgeedge with one ZnO6 octahedra, and edges with five CoO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.03–2.12 Å. In the fifth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with six CoO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four equivalent CoO6 octahedra. There are four shorter (2.05 Å) and two longer (2.10 Å) Zn–O bond lengths. In the sixth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with six CoO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four CoO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.05–2.11 Å. In the seventh Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share a cornercorner with one ZnO4 tetrahedra, corners with five CoO4 tetrahedra, an edgeedge with one ZnO6 octahedra, and edges with five CoO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.05–2.09 Å. In the eighth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with six CoO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four CoO6 octahedra. There are four shorter (2.06 Å) and two longer (2.11 Å) Zn–O bond lengths. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Co3+ and two Zn2+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Co3+ and two Zn2+ atoms. In the third O2- site, O2- is bonded to three Co3+ and one Zn2+ atom to form distorted OZnCo3 trigonal pyramids that share a cornercorner with one OZn2Co2 tetrahedra and corners with three OCo4 trigonal pyramids. In the fourth O2- site, O2- is bonded to four Co3+ atoms to form distorted corner-sharing OCo4 trigonal pyramids. In the fifth O2- site, O2- is bonded to two Co3+ and two Zn2+ atoms to form a mixture of distorted edge and corner-sharing OZn2Co2 trigonal pyramids. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co3+ and one Zn2+ atom. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co3+ and one Zn2+ atom. In the eighth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co3+ and one Zn2+ atom. In the ninth O2- site, O2- is bonded to three Co3+ and one Zn2+ atom to form distorted OZnCo3 trigonal pyramids that share corners with five OZnCo3 trigonal pyramids and edges with two equivalent OZn2Co2 trigonal pyramids. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Co3+ and two Zn2+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co3+ and one Zn2+ atom. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Co3+ and two Zn2+ atoms. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co3+ and one Zn2+ atom. In the fourteenth O2- site, O2- is bonded to three Co3+ and one Zn2+ atom to form distorted corner-sharing OZnCo3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co3+ and one Zn2+ atom. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co3+ and one Zn2+ atom. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Co3+ and two Zn2+ atoms. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Co3+ and two Zn2+ atoms. In the nineteenth O2- site, O2- is bonded to two equivalent Co3+ and two Zn2+ atoms to form distorted corner-sharing OZn2Co2 tetrahedra. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co3+ and one Zn2+ atom. In the twenty-first O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co3+ and one Zn2+ atom. In the twenty-second O2- site, O2- is bonded to four Co3+ atoms to form distorted OCo4 trigonal pyramids that share corners with two equivalent OZn2Co2 tetrahedra and a cornercorner with one OZnCo3 trigonal pyramid. In the twenty-third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co3+ and one Zn2+ atom. In the twenty-fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co3+ and one Zn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zn(FeO2)2 by Materials Project

ZnFe2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are fifteen inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with two equivalent ZnO6 octahedra and corners with ten FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–59°. There are a spread of Fe–O bond distances ranging from 1.93–1.97 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.11 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, an edgeedge with one ZnO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.02–2.10 Å. In the fourth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–58°. There are a spread of Fe–O bond distances ranging from 1.93–1.99 Å. In the fifth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.12 Å. In the sixth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.03–2.08 Å. In the seventh Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–58°. There are a spread of Fe–O bond distances ranging from 1.93–1.99 Å. In the eighth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.11 Å. In the ninth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.03–2.08 Å. In the tenth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 57–59°. There are a spread of Fe–O bond distances ranging from 1.93–1.98 Å. In the eleventh Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO4 tetrahedra, corners with four ZnO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.02–2.11 Å. In the twelfth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.03–2.09 Å. In the thirteenth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one FeO4 tetrahedra, corners with five ZnO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.03–2.11 Å. In the fourteenth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one FeO4 tetrahedra, corners with five ZnO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.02–2.11 Å. In the fifteenth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six ZnO4 tetrahedra, an edgeedge with one ZnO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.11 Å. There are ten inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share a cornercorner with one ZnO6 octahedra and corners with eleven FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are one shorter (1.99 Å) and three longer (2.01 Å) Zn–O bond lengths. In the second Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.10–2.15 Å. In the third Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–59°. There are a spread of Zn–O bond distances ranging from 1.98–2.03 Å. In the fourth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.10–2.14 Å. In the fifth Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 57–59°. There are a spread of Zn–O bond distances ranging from 1.98–2.03 Å. In the sixth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.10–2.14 Å. In the seventh Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Zn–O bond distances ranging from 1.96–2.03 Å. In the eighth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with two equivalent FeO4 tetrahedra, corners with four ZnO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.09–2.14 Å. In the ninth Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share a cornercorner with one ZnO6 octahedra and corners with eleven FeO6 octahedra. The corner-sharing octahedra tilt angles range from 57–62°. There are a spread of Zn–O bond distances ranging from 1.98–2.04 Å. In the tenth Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with two equivalent ZnO6 octahedra and corners with ten FeO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There are a spread of Zn–O bond distances ranging from 1.98–2.04 Å. There are thirty inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the second O2- site, O2- is bonded to three Fe3+ and one Zn2+ atom to form a mixture of distorted edge and corner-sharing OZnFe3 trigonal pyramids. In the third O2- site, O2- is bonded to four Fe3+ atoms to form a mixture of distorted edge and corner-sharing OFe4 trigonal pyramids. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the seventh O2- site, O2- is bonded to three Fe3+ and one Zn2+ atom to form a mixture of distorted edge and corner-sharing OZnFe3 trigonal pyramids. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Fe3+ and two Zn2+ atoms. In the ninth O2- site, O2- is bonded to four Fe3+ atoms to form a mixture of distorted edge and corner-sharing OFe4 trigonal pyramids. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the eleventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the thirteenth O2- site, O2- is bonded to three Fe3+ and one Zn2+ atom to form distorted edge-sharing OZnFe3 trigonal pyramids. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Fe3+ and two Zn2+ atoms. In the fifteenth O2- site, O2- is bonded to four Fe3+ atoms to form a mixture of distorted edge and corner-sharing OFe4 trigonal pyramids. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the eighteenth O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to two equivalent Fe3+ and two Zn2+ atoms. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Fe3+ and two Zn2+ atoms. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe3+ atoms. In the twenty-second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twenty-third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twenty-fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Fe3+ and two Zn2+ atoms. In the twenty-fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe3+ atoms. In the twenty-sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the twenty-seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twenty-eighth O2- site, O2- is bonded to three Fe3+ and one Zn2+ atom to form a mixture of distorted edge and corner-sharing OZnFe3 trigonal pyramids. In the twenty-ninth O2- site, O2- is bonded to three Fe3+ and one Zn2+ atom to form a mixture of distorted edge and corner-sharing OZnFe3 trigonal pyramids. In the thirtieth O2- site, O2- is bonded to three Fe3+ and one Zn2+ atom to form distorted edge-sharing OZnFe3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zn(FeO2)2 by Materials Project

ZnFe2O4 is Spinel-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twenty inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, edges with three FeO6 octahedra, and edges with three ZnO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.01–2.09 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.99–2.10 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.99–2.11 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.09 Å. In the fifth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.98–2.10 Å. In the sixth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There are a spread of Fe–O bond distances ranging from 1.92–1.97 Å. In the seventh Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.96–2.14 Å. In the eighth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.02–2.08 Å. In the ninth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with five ZnO6 octahedra and corners with seven FeO6 octahedra. The corner-sharing octahedra tilt angles range from 51–61°. There are a spread of Fe–O bond distances ranging from 1.91–1.96 Å. In the tenth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four FeO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.99–2.10 Å. In the eleventh Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There is two shorter (1.92 Å) and two longer (1.95 Å) Fe–O bond length. In the twelfth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four FeO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.99–2.10 Å. In the thirteenth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with three FeO6 octahedra, and edges with three ZnO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.98–2.04 Å. In the fourteenth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six FeO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 53–60°. There are a spread of Fe–O bond distances ranging from 1.90–1.96 Å. In the fifteenth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with two FeO6 octahedra, and edges with four ZnO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.95–2.02 Å. In the sixteenth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four ZnO6 octahedra and corners with eight FeO6 octahedra. The corner-sharing octahedra tilt angles range from 53–60°. There are a spread of Fe–O bond distances ranging from 1.89–2.01 Å. In the seventeenth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with two FeO6 octahedra, and edges with four ZnO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.97–2.02 Å. In the eighteenth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one ZnO4 tetrahedra, corners with five FeO4 tetrahedra, edges with two FeO6 octahedra, and edges with four ZnO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.10 Å. In the nineteenth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six FeO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 55–59°. There are a spread of Fe–O bond distances ranging from 1.88–1.99 Å. In the twentieth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with five ZnO6 octahedra and corners with seven FeO6 octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Fe–O bond distances ranging from 1.89–1.95 Å. There are ten inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with four ZnO6 octahedra and corners with eight FeO6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There are a spread of Zn–O bond distances ranging from 1.96–2.02 Å. In the second Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–59°. There are a spread of Zn–O bond distances ranging from 1.97–1.99 Å. In the third Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–61°. There are a spread of Zn–O bond distances ranging from 1.97–2.03 Å. In the fourth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.09–2.13 Å. In the fifth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with three FeO4 tetrahedra, corners with three ZnO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.06–2.14 Å. In the sixth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with six FeO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.07–2.18 Å. In the seventh Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four FeO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.08–2.14 Å. In the eighth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with six FeO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.07–2.17 Å. In the ninth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share a cornercorner with one ZnO4 tetrahedra, corners with five FeO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.01–2.20 Å. In the tenth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share a cornercorner with one ZnO4 tetrahedra, corners with five FeO4 tetrahedra, edges with two equivalent ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.02–2.19 Å. There are forty inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe3+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to three Fe3+ and one Zn2+ atom. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe3+ atoms. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the twenty-first O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twenty-second O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twenty-third O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twenty-fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twenty-fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the twenty-sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twent

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zn(GaS2)2 by Materials Project

ZnGa2S4 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. there are three inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (2.87 Å) and four longer (2.89 Å) Zn–S bond lengths. In the second Zn2+ site, Zn2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (2.83 Å) and four longer (2.99 Å) Zn–S bond lengths. In the third Zn2+ site, Zn2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Zn–S bond distances ranging from 2.72–3.14 Å. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four S2- atoms to form a mixture of edge and corner-sharing GaS4 tetrahedra. There are a spread of Ga–S bond distances ranging from 2.28–2.32 Å. In the second Ga3+ site, Ga3+ is bonded to four S2- atoms to form a mixture of edge and corner-sharing GaS4 tetrahedra. There are a spread of Ga–S bond distances ranging from 2.30–2.32 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 2-coordinate geometry to two Zn2+ and two equivalent Ga3+ atoms. In the second S2- site, S2- is bonded in a 4-coordinate geometry to two Zn2+ and two equivalent Ga3+ atoms. In the third S2- site, S2- is bonded to two Zn2+ and two Ga3+ atoms to form a mixture of distorted edge and corner-sharing SZn2Ga2 trigonal pyramids. In the fourth S2- site, S2- is bonded in a 4-coordinate geometry to two Zn2+ and two Ga3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Reactivity of Zn + aq in high-temperature water radiolysis

For this work, reactivity of transients involving Zn + in high-temperature water radiolysis has been studied in the temperature range of 25–300 °C. The reduced monovalent zinc species were generated from an electron transfer process between the hydrated electron and Zn 2+ ions using pulse radiolysis. The Zn + species can subsequently be oxidized by the radiolytically-produced oxidizing species: ˙OH, H 2 O 2 and ˙H. We find that the absorption of monovalent zinc is very sensitive to the pH of the medium. An absorption maximum at 306–311 nm is most pronounced at pH 7 and the signal then decreases in acidic media where the reducing electrons are competitively captured by protons. At pH values higher than 7, hydroxo-forms of Zn 2+ are created and the maximum of the absorption signal begins to shift to the red spectral region. We find that the optical spectrum of Zn + aq cannot be fully explained in terms of a charge-transfer to solvent (CTTS) process, which was previously proposed. Reaction rates of most of the recombination reactions investigated follow the empirical Arrhenius relationship at temperatures up to 200 °C and have been determined at higher temperatures for the first time. A bimolecular disproportionation reaction of Zn + aq is not observed under the conditions investigated.

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

Boosting Photoelectric Conductivity in Porphyrin-Based MOFs Incorporating C 60

Electronic structure calculations show that guest C60 in the porphyrin-containing metal organic frameworks Zn 2 (TCPB)(DA-ZnP) (DA-MOF; H 4 TCPB = 1,2,4,5-tetrakis(4-carboxyphenyl)benzene, DA-ZnP = [5,15-bis[(4-pyridyl)ethynyl]-10,20-diphenylporphinato]zinc(II)) and Zn 2 (TCPB)(F-ZnP) (F-MOF; F-ZnP = [5,15-di(4-pyridyl)-10,20-bis(pentafluorophenyl)porphinato]zinc(II)) engenders high photoelectrical conductivity due to efficient donor–acceptor charge-transfer (CT) interactions. Structural modifications at the meso position of the porphyrin influence the preferred positions of C 60 within the frameworks, giving rise to host–guest interactions with different anisotropic structural, electronic, and optoelectronic properties. A preferred slipped-parallel π-stacked interaction of C 60 that is predicted for NH 2 -substituted DA-MOF and F-MOF fosters strong CT transitions and lowers band gaps by ~1.0 eV compared to the pristine DA-MOF and F-MOF. Hopping rates computed using Marcus theory are found to be anisotropic and accelerated by multiple orders of magnitude across π-stacked interfaces created by C 60 incorporation, a consequence of strong electronic coupling between initial and final diabatic states. Calculations indicate that photoinduced electron transfer, as well as direct CT from porphyrin to C 60 upon irradiation, triggers a charge separation process that leads to the formation of what should be long-lived electron-trapped states at the heterojunctions. Lastly, design principles revealed here for the control of photophysical and electron-transfer processes will be useful for constructing new MOF-derived visible- and infrared-based optoelectronics.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Formation of zinc carbonate phases on dissolving calcite, aragonite, and vaterite in acidic aqueous solutions

Calcium carbonate (CaCO 3 ) minerals serve as a major sink to retain metal ions through mineral-water interfacial reactions in which the capacity and long-term stability of contaminant uptake are influenced by coupled dissolution and precipitation reactions of both primary and secondary carbonate minerals (i.e., mineral replacement). Notably, recent studies of calcite reactivity in acidic solutions containing high levels of metal ions demonstrated complex behavior under conditions of sustained disequilibrium. Here, we explored the reactivity of three CaCO 3 polymorphs (calcite, aragonite, and vaterite) with acidic Zn 2+ -containing aqueous solutions using a suite of imaging techniques including optical and scanning electron microscopies, synchrotron-based micro X-ray fluorescence, and transmission X-ray microscopy. Zn uptake by calcite occurred through a two-step process: the formation of a thin layer of the zinc precipitate on the substrate surface followed by the growth of fibrous and radiating hydrozincite particles from the layer. In contrast, Zn uptake by aragonite occurred by mineral replacement where the secondary Zn carbonate phase preserved the external morphology of the original crystal (i.e., a pseudomorph). The replacement of vaterite by hydrozincite occurred within the confined space beneath the porous shell of vaterite, signifying that the primary mechanism driving Zn carbonate precipitation was chemical exchange through the pores. When multiple CaCO 3 polymorphs coexisted, the replacement of aragonite and vaterite occurred preferentially over that of calcite. These results demonstrate the distinct morphological and mineralogical controls over the reactivities of calcium carbonate minerals with Zn 2+ under acidic conditions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

The Mycobacterium tuberculosis mycothiol S -transferase is divalent metal-dependent for mycothiol binding and transfer

Mycothiol S-transferase (MST) (encoded by the rv0443 gene) was previously identified as the enzyme responsible for the transfer of Mycothiol (MSH) to xenobiotic acceptors in Mycobacterium tuberculosis (M.tb) during xenobiotic stress. To further characterize the functionality of MST in vitro and the possible roles in vivo, X-ray crystallographic, metal-dependent enzyme kinetics, thermal denaturation studies, and antibiotic MIC determination in rv0433 knockout strain were performed. The binding of MSH and Zn 2+ increases the melting temperature by 12.9 °C as a consequence of the cooperative stabilization of MST by both MSH and metal. The co-crystal structure of MST in complex with MSH and Zn 2+ to 1.45 Å resolution supports the specific utilization of MSH as a substrate as well as affording insights into the structural requirements of MSH binding and the metal-assisted catalytic mechanism of MST. Further, contrary to the well-defined role of MSH in mycobacterial xenobiotic responses and the ability of MST to bind MSH, cell-based studies with an M.tb rv0443 knockout strain failed to provide evidence for a role of MST in processing of rifampicin or isoniazid. These studies suggest the necessity of a new direction to identify acceptors of the enzyme and better define the biological role of MST in mycobacteria.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Vibrational modes and crystallographic structure of Cd 3 As 2 and (Cd 1-x Zn x ) 3 As 2 epilayers

Low-temperature Raman scattering is used to study the crystal structure of molecular-beam epitaxially grown layers of the Dirac semimetal Cd 3 As 2 and its related alloy (Cd 1-x Zn x ) 3 As 2 . The combination of narrow-linewidth spectra, multiple growth directions and full polarization analysis allows improved accuracy in identifying the irreducible representation of over 57 Raman-active vibrations. Several disagreements with previous identifications are found. Structurally, the results agree with the centrosymmetric I41/acd space group of bulk-grown Cd 3 As 2 and are clearly distinct from the Raman spectra of nanoscale platelets and wires. Three-fold twinning is seen in (112) Cd 3 As 2 grown on (111) zincblende substrates corresponding to the three possible tetragonal orientations. In dilute (Cd 1-x Zn x ) 3 As 2 , phonons have a frequency and scattering amplitude dependence on Zn concentration that is continuous with Cd 3 As 2 but at least one frequency is absent at the alloy endpoint, preventing a simple one-mode description of the alloy phonon.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Reversible Cl/Cl - redox in a spinel Mn 3 O 4 electrode

A unique prospect of using halides as charge carriers is the possibility of the halides undergoing anodic redox behaviors when serving as charge carriers for the charge-neutrality compensation of electrodes. However, the anodic conversion of halides to neutral halogen species has often been irreversible at room temperature due to the emergence of diatomic halogen gaseous products. Here, we report that chloride ions can be reversibly converted to near-neutral atomic chlorine species in the Mn 3 O 4 electrode at room temperature in a highly concentrated chloride-based aqueous electrolyte. Notably, the Zn 2+ cations inserted in the first discharge and trapped in the Mn 3 O 4 structure create an environment to stabilize the converted chlorine atoms within the structure. Characterization results suggest that the Cl/Cl - redox is responsible for the observed large capacity, as the oxidation state of Mn barely changes upon charging. Computation results corroborate that the converted chlorine species exist as polychloride monoanions, e.g., [Cl 3 ] - and [Cl 5 ] - , inside the Zn 2+ -trapped Mn 3 O 4 , and the presence of polychloride species is confirmed experimentally. Our results point to the halogen plating inside electrode lattices as a new charge-storage mechanism.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Local structure and ion storage properties of vanadate cathode materials regulated by the pre-alkalization

Aqueous Zn-ion batteries using mild acidic electrolytes utilizing a Zn 2+ /H + dual-ion storage mechanism have shown great potential in achieving high energy density comparable to non-aqueous lithium-ion batteries. Here, this study reveals that hydrated alkali-ions regulate the formation of alkali-intercalated vanadate layered compounds. Among various vanadate materials, lithium-intercalated vanadate has the largest interlayer spacing and most disordered local structure, exhibiting the largest storage capacity of 308 mA h g –1 at 0.05 A g –1 for Zn 2+ /H + dual-ion storage and improved charge transfer and transport kinetics and cycling performance, evidenced by in situ X-ray diffraction and ex situ X-ray total scattering and pair distribution function analysis. Our study provides new insight into designing layered vanadate materials for high-capacity aqueous batteries.

25 ENERGY STORAGE↗
DOE OSTI2022

Time-resolved β-lactam cleavage by L1 metallo-β-lactamase

Abstract Serial x-ray crystallography can uncover binding events, and subsequent chemical conversions occurring during enzymatic reaction. Here, we reveal the structure, binding and cleavage of moxalactam antibiotic bound to L1 metallo-β-lactamase (MBL) from Stenotrophomonas maltophilia . Using time-resolved serial synchrotron crystallography, we show the time course of β-lactam hydrolysis and determine ten snapshots (20, 40, 60, 80, 100, 150, 300, 500, 2000 and 4000 ms) at 2.20 Å resolution. The reaction is initiated by laser pulse releasing Zn 2+ ions from a UV-labile photocage. Two metal ions bind to the active site, followed by binding of moxalactam and the intact β-lactam ring is observed for 100 ms after photolysis. Cleavage of β-lactam is detected at 150 ms and the ligand is significantly displaced. The reaction product adjusts its conformation reaching steady state at 2000 ms corresponding to the relaxed state of the enzyme. Only small changes are observed in the positions of Zn 2+ ions and the active site residues. Mechanistic details captured here can be generalized to other MBLs.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1986

The adsorption and reaction of adenine nucleotides on montmorillonite

The binding of AMP to Zn(2+)-montmorillonite is investigated in the presence of salts and Good's zwitterion buffers, PIPES and MES. The initial concentrations of nucleotide and the percent adsorbtion are used to calculate the adsorption isotherms, and the Langmuir adsorption equation is used for the analysis of data. The adsorption coefficient was found to be three times greater in the presence of 0.2 M PIPES than in its absence. In addition, basal spacings measured by X-ray diffraction were increased by the buffer. These results are interpreted in terms of a model in which the adsorption of AMP is mediated by a Zn(2+) complex of PIPES in different orientations in the interlamellar region of the montmorillonite. Mixed ligand complexes of this type are reminiscent of the complexes observed between metal ions and biological molecules in living systems.

Ferris, James P.↗
DOE OSTI2025

Surviving nanoscale interfacial stability in extreme thermal expansion contrast Zn(CN) 2 -epoxy resin matrix composites

Here, we report the remarkable stability at the nanoscale matrix-filler interface in a series of overall low coefficient of thermal expansion (CTE) zinc cyanide (ZC)/epoxy resin composites. These interfaces demonstrate the stability of highly contrasting materials. These composites are designed to optimize the properties of both materials: epoxy resins are valued for their high strength, superb chemical resistance, low dielectric properties, and adhesive abilities. ZC, a model flexible framework, exhibits negative thermal expansion (NTE) behavior and compensates for the epoxy resin’s detrimentally large thermal expansion values. Filled resins minimize the native 65 ppm/°C CTE values to 19 ppm/° C over a wide temperature range while maintaining linearity, yielding composites compatible with typical metal and ceramic substrates’—commonly bonded to the resin— 0–20 ppm/° C CTE values. Additionally, with significant intrinsic differences in the materials, we use wide-angle X-ray diffraction and atomic force microscopy to elucidate thermal movement. The ZC/epoxy interface is surprisingly resilient over 1,000 cycles between -55° C and 75° C, extremes typical to aerospace applications. Further, we show that the resin viscosity remains less than 21 Pa*s at up to 30 vol% ZC, an important consideration for workability. We also discuss settling distribution, glass transition temperature, flexural strength, and longevity. All results point favorably towards practical implementation in low thermal expansion application needs: filling the gap in component design.

42 ENGINEERING↗