Search NASA⌕ Search

DOE OSTI · 1276903

Materials Data on CsNa5(WN3)2 by Materials Project

Abstract

CsNa5(WN3)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to four N3- atoms. There are a spread of Cs–N bond distances ranging from 3.13–3.33 Å. In the second Cs1+ site, Cs1+ is bonded in a 3-coordinate geometry to three N3- atoms. There are two shorter (3.06 Å) and one longer (3.27 Å) Cs–N bond lengths. There are ten inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 3-coordinate geometry to five N3- atoms. There are a spread of Na–N bond distances ranging from 2.43–3.02 Å. In the second Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of Na–N bond distances ranging from 2.49–2.69 Å. In the third Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of Na–N bond distances ranging from 2.55–2.78 Å. In the fourth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of Na–N bond distances ranging from 2.52–3.12 Å. In the fifth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four N3- atoms. There are a spread of Na–N bond distances ranging from 2.45–2.74 Å. In the sixth Na1+ site, Na1+ is bonded to four N3- atoms to form distorted NaN4 tetrahedra that share corners with four WN4 tetrahedra and an edgeedge with one NaN4 tetrahedra. There are a spread of Na–N bond distances ranging from 2.42–2.55 Å. In the seventh Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of Na–N bond distances ranging from 2.42–2.88 Å. In the eighth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of Na–N bond distances ranging from 2.52–2.82 Å. In the ninth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of Na–N bond distances ranging from 2.53–2.94 Å. In the tenth Na1+ site, Na1+ is bonded to four N3- atoms to form distorted NaN4 tetrahedra that share corners with four WN4 tetrahedra and an edgeedge with one NaN4 tetrahedra. There are a spread of Na–N bond distances ranging from 2.47–2.51 Å. There are four inequivalent W6+ sites. In the first W6+ site, W6+ is bonded to four N3- atoms to form WN4 tetrahedra that share corners with two NaN4 tetrahedra and corners with two WN4 tetrahedra. There are a spread of W–N bond distances ranging from 1.83–1.93 Å. In the second W6+ site, W6+ is bonded to four N3- atoms to form WN4 tetrahedra that share corners with two WN4 tetrahedra and corners with four NaN4 tetrahedra. There are a spread of W–N bond distances ranging from 1.84–1.94 Å. In the third W6+ site, W6+ is bonded to four N3- atoms to form WN4 tetrahedra that share corners with two NaN4 tetrahedra and corners with two WN4 tetrahedra. There are a spread of W–N bond distances ranging from 1.84–1.96 Å. In the fourth W6+ site, W6+ is bonded to four N3- atoms to form corner-sharing WN4 tetrahedra. There are a spread of W–N bond distances ranging from 1.84–1.94 Å. There are twelve inequivalent N3- sites. In the first N3- site, N3- is bonded in a 6-coordinate geometry to one Cs1+, four Na1+, and one W6+ atom. In the second N3- site, N3- is bonded to four Na1+ and two W6+ atoms to form distorted corner-sharing NNa4W2 octahedra. The corner-sharing octahedral tilt angles are 45°. In the third N3- site, N3- is bonded in a 5-coordinate geometry to one Cs1+, three Na1+, and one W6+ atom. In the fourth N3- site, N3- is bonded in a 7-coordinate geometry to one Cs1+, five Na1+, and one W6+ atom. In the fifth N3- site, N3- is bonded in a 6-coordinate geometry to five Na1+ and one W6+ atom. In the sixth N3- site, N3- is bonded in a 7-coordinate geometry to one Cs1+, five Na1+, and one W6+ atom. In the seventh N3- site, N3- is bonded in a 6-coordinate geometry to one Cs1+, three Na1+, and two W6+ atoms. In the eighth N3- site, N3- is bonded in a 6-coordinate geometry to one Cs1+, three Na1+, and two W6+ atoms. In the ninth N3- site, N3- is bonded in a 3-coordinate geometry to one Cs1+, three Na1+, and one W6+ atom. In the tenth N3- site, N3- is bonded in a 6-coordinate geometry to five Na1+ and one W6+ atom. In the eleventh N3- site, N3- is bonded to four Na1+ and two W6+ atoms to form corner-sharing NNa4W2 octahedra. The corner-sharing octahedral tilt angles are 45°. In the twelfth N3- site, N3- is bonded in a 5-coordinate geometry to four Na1+ and one W6+ atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-02. Materials Data on CsNa5(WN3)2 by Materials Project. https://doi.org/10.17188/1276903

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↗