Search NASA⌕ Search

DOE OSTI · 1681833

Materials Data on Na2GdMnAs2O9 by Materials Project

Abstract

Na2GdMnAs2O9 is Esseneite-derived structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.52–2.66 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.52–2.66 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.42–2.85 Å. In the fourth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.42–2.85 Å. There are two inequivalent Gd3+ sites. In the first Gd3+ site, Gd3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Gd–O bond distances ranging from 2.30–2.57 Å. In the second Gd3+ site, Gd3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Gd–O bond distances ranging from 2.30–2.58 Å. There are four inequivalent Mn3+ sites. In the first Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four AsO4 tetrahedra and edges with two equivalent MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.91–2.16 Å. In the second Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four AsO4 tetrahedra and edges with two equivalent MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.91–2.15 Å. In the third Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four AsO4 tetrahedra and edges with two equivalent MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.92–2.16 Å. In the fourth Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four AsO4 tetrahedra and edges with two equivalent MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.93–2.15 Å. There are four inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two MnO6 octahedra. The corner-sharing octahedra tilt angles range from 45–50°. There are a spread of As–O bond distances ranging from 1.70–1.75 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two MnO6 octahedra. The corner-sharing octahedra tilt angles range from 44–50°. There are a spread of As–O bond distances ranging from 1.70–1.75 Å. In the third As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two MnO6 octahedra. The corner-sharing octahedra tilt angles range from 55–59°. There are a spread of As–O bond distances ranging from 1.70–1.75 Å. In the fourth As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two MnO6 octahedra. The corner-sharing octahedra tilt angles range from 55–59°. There are a spread of As–O bond distances ranging from 1.70–1.75 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded to one Na1+, one Gd3+, and two Mn3+ atoms to form a mixture of distorted corner and edge-sharing ONaGdMn2 tetrahedra. In the second O2- site, O2- is bonded to one Na1+, one Gd3+, and two Mn3+ atoms to form a mixture of distorted corner and edge-sharing ONaGdMn2 tetrahedra. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two Mn3+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Mn3+ and one As5+ atom. In the fifth O2- site, O2- is bonded to one Na1+, one Gd3+, one Mn3+, and one As5+ atom to form distorted ONaGdMnAs tetrahedra that share corners with two ONaGdMnAs tetrahedra, a cornercorner with one ONaGdMnAs trigonal pyramid, an edgeedge with one ONaGdMn2 tetrahedra, and an edgeedge with one ONaGdMnAs trigonal pyramid. In the sixth O2- site, O2- is bonded to one Na1+, one Gd3+, one Mn3+, and one As5+ atom to form distorted ONaGdMnAs tetrahedra that share corners with two ONaGdMnAs tetrahedra, a cornercorner with one ONaGdMnAs trigonal pyramid, an edgeedge with one ONaGdMn2 tetrahedra, and an edgeedge with one ONaGdMnAs trigonal pyramid. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Gd3+, and one As5+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Gd3+, and one As5+ atom. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one Gd3+ and one As5+ atom. In the tenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Gd3+ and one As5+ atom. In the eleventh O2- site, O2- is bonded to one Na1+, one Gd3+, one Mn3+, and one As5+ atom to form distorted ONaGdMnAs trigonal pyramids that share corners with two ONaGdMnAs tetrahedra, a cornercorner with one ONaGdMnAs trigonal pyramid, and edges with two ONaGdMn2 tetrahedra. In the twelfth O2- site, O2- is bonded to one Na1+, one Gd3+, one Mn3+, and one As5+ atom to form distorted ONaGdMnAs trigonal pyramids that share corners with two ONaGdMnAs tetrahedra, a cornercorner with one ONaGdMnAs trigonal pyramid, and edges with two ONaGdMn2 tetrahedra. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Gd3+, and one As5+ atom. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Gd3+, and one As5+ atom. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Gd3+, and one As5+ atom. In the sixteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Gd3+, and one As5+ atom. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Gd3+, and one As5+ atom. In the eighteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Gd3+, and one As5+ atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-06-04. Materials Data on Na2GdMnAs2O9 by Materials Project. https://doi.org/10.17188/1681833

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

Cyclic moisture reactivation of calcium sorbents for long duration thermochemical energy storage

The transition to a flexible and reliable energy infrastructure, using electro-thermal energy generation technologies such as geothermal, concentrated solar power, and nuclear, usually demands simultaneous advancement of thermal energy storage (TES) to support on-demand electricity generation and industrial applications while mitigating the inherent intermittency of renewable energy sources and power outages from direct energy generation. Among TES technologies, thermochemical energy storage (TCES) based on calcium looping emerges as a compelling high-power energy storage candidate due to its high reaction enthalpy, compatibility with elevated operating temperatures, and abundance of low-cost materials. However, the long-term durability of calcium-based sorbents for TCES is hindered by surface sintering and particle aggregation, leading to performance degradation over repeated thermal cycles. This study explores a moisture hydration-based strategy to regenerate a degraded calcium sorbent and mitigate performance degradation for long duration TCES. The addition of moisture transforms calcium oxide into calcium hydroxide and produces intercalation water layers, associated with a regenerated surface area and reduced calcium oxide crystallite size. Both these effects are beneficial in restoring the sorbents' reactivity for carbonization. Additionally, an optimized hydration-assisted reactivation protocol balances the recovered energy storage capacity with heating penalty required for moisture removal from hydrated samples, resulting in an enhanced energy storage capacity up to 176% compared to benchmark sorbents that undergo cycling without reactivation after 60 cycles. In conclusion, these results highlight the potential of hydration-assisted reactivation to enhance the long-term performance of TCES, providing an effective pathway to advancing electro-thermal storage technologies.

36 MATERIALS SCIENCE↗