Search NASA⌕ Search

DOE OSTI · 1285450

Materials Data on Nd5Fe5As5O4F by Materials Project

Abstract

Nd5Fe5As5O4F crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Nd+2.80+ sites. In the first Nd+2.80+ site, Nd+2.80+ is bonded in a 4-coordinate geometry to four As3-, three O2-, and one F1- atom. There are a spread of Nd–As bond distances ranging from 3.25–3.38 Å. There are one shorter (2.34 Å) and two longer (2.36 Å) Nd–O bond lengths. The Nd–F bond length is 2.49 Å. In the second Nd+2.80+ site, Nd+2.80+ is bonded in a 4-coordinate geometry to four As3- and four O2- atoms. There are a spread of Nd–As bond distances ranging from 3.33–3.36 Å. All Nd–O bond lengths are 2.38 Å. In the third Nd+2.80+ site, Nd+2.80+ is bonded in a 4-coordinate geometry to four As3-, three O2-, and one F1- atom. There are a spread of Nd–As bond distances ranging from 3.25–3.34 Å. There are one shorter (2.34 Å) and two longer (2.36 Å) Nd–O bond lengths. The Nd–F bond length is 2.49 Å. In the fourth Nd+2.80+ site, Nd+2.80+ is bonded in a 4-coordinate geometry to four As3-, three O2-, and one F1- atom. There are a spread of Nd–As bond distances ranging from 3.23–3.36 Å. There are one shorter (2.34 Å) and two longer (2.37 Å) Nd–O bond lengths. The Nd–F bond length is 2.48 Å. In the fifth Nd+2.80+ site, Nd+2.80+ is bonded in a 4-coordinate geometry to four As3-, three O2-, and one F1- atom. There are a spread of Nd–As bond distances ranging from 3.22–3.38 Å. There are one shorter (2.34 Å) and two longer (2.36 Å) Nd–O bond lengths. The Nd–F bond length is 2.47 Å. There are five inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four As3- atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. There are a spread of Fe–As bond distances ranging from 2.63–2.66 Å. In the second Fe2+ site, Fe2+ is bonded to four As3- atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. There are three shorter (2.62 Å) and one longer (2.63 Å) Fe–As bond lengths. In the third Fe2+ site, Fe2+ is bonded to four As3- atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. There are a spread of Fe–As bond distances ranging from 2.62–2.65 Å. In the fourth Fe2+ site, Fe2+ is bonded to four As3- atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. There are a spread of Fe–As bond distances ranging from 2.61–2.64 Å. In the fifth Fe2+ site, Fe2+ is bonded to four As3- atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. There are a spread of Fe–As bond distances ranging from 2.62–2.64 Å. There are five inequivalent As3- sites. In the first As3- site, As3- is bonded in a 8-coordinate geometry to four Nd+2.80+ and four Fe2+ atoms. In the second As3- site, As3- is bonded in a 8-coordinate geometry to four Nd+2.80+ and four Fe2+ atoms. In the third As3- site, As3- is bonded in a 8-coordinate geometry to four Nd+2.80+ and four Fe2+ atoms. In the fourth As3- site, As3- is bonded in a 8-coordinate geometry to four Nd+2.80+ and four Fe2+ atoms. In the fifth As3- site, As3- is bonded in a 8-coordinate geometry to four Nd+2.80+ and four Fe2+ atoms. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four Nd+2.80+ atoms to form distorted ONd4 tetrahedra that share a cornercorner with one FNd4 tetrahedra, corners with three ONd4 tetrahedra, an edgeedge with one FNd4 tetrahedra, and edges with three ONd4 tetrahedra. In the second O2- site, O2- is bonded to four Nd+2.80+ atoms to form distorted ONd4 tetrahedra that share a cornercorner with one FNd4 tetrahedra, corners with three ONd4 tetrahedra, an edgeedge with one FNd4 tetrahedra, and edges with three ONd4 tetrahedra. In the third O2- site, O2- is bonded to four Nd+2.80+ atoms to form distorted ONd4 tetrahedra that share a cornercorner with one FNd4 tetrahedra, corners with three ONd4 tetrahedra, an edgeedge with one FNd4 tetrahedra, and edges with three ONd4 tetrahedra. In the fourth O2- site, O2- is bonded to four Nd+2.80+ atoms to form distorted ONd4 tetrahedra that share a cornercorner with one FNd4 tetrahedra, corners with three ONd4 tetrahedra, an edgeedge with one FNd4 tetrahedra, and edges with three ONd4 tetrahedra. F1- is bonded to four Nd+2.80+ atoms to form distorted FNd4 tetrahedra that share corners with four ONd4 tetrahedra and edges with four ONd4 tetrahedra.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-08-03. Materials Data on Nd5Fe5As5O4F by Materials Project. https://doi.org/10.17188/1285450

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↗