Search NASA⌕ Search

DOE OSTI · 1283265

Materials Data on Ca2YbF7 by Materials Project

Abstract

Ca2YbF7 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one Ca2YbF7 sheet oriented in the (1, 1, -1) direction. there are ten inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 3-coordinate geometry to five F1- atoms. There are a spread of Ca–F bond distances ranging from 1.74–3.00 Å. In the second Ca2+ site, Ca2+ is bonded in a 2-coordinate geometry to five F1- atoms. There are a spread of Ca–F bond distances ranging from 1.64–2.64 Å. In the third Ca2+ site, Ca2+ is bonded in a distorted bent 150 degrees geometry to four F1- atoms. There are a spread of Ca–F bond distances ranging from 1.50–2.67 Å. In the fourth Ca2+ site, Ca2+ is bonded in a 3-coordinate geometry to four F1- atoms. There are a spread of Ca–F bond distances ranging from 1.68–2.40 Å. In the fifth Ca2+ site, Ca2+ is bonded in a 3-coordinate geometry to four F1- atoms. There are a spread of Ca–F bond distances ranging from 1.70–2.42 Å. In the sixth Ca2+ site, Ca2+ is bonded in a distorted bent 150 degrees geometry to four F1- atoms. There are a spread of Ca–F bond distances ranging from 1.49–2.65 Å. In the seventh Ca2+ site, Ca2+ is bonded in a distorted linear geometry to two F1- atoms. There is one shorter (1.49 Å) and one longer (1.51 Å) Ca–F bond length. In the eighth Ca2+ site, Ca2+ is bonded in a 2-coordinate geometry to two F1- atoms. There is one shorter (1.65 Å) and one longer (1.90 Å) Ca–F bond length. In the ninth Ca2+ site, Ca2+ is bonded in a 1-coordinate geometry to six F1- atoms. There are a spread of Ca–F bond distances ranging from 1.68–2.99 Å. In the tenth Ca2+ site, Ca2+ is bonded in a 1-coordinate geometry to five F1- atoms. There are a spread of Ca–F bond distances ranging from 1.73–3.08 Å. There are five inequivalent Yb3+ sites. In the first Yb3+ site, Yb3+ is bonded in a 2-coordinate geometry to three F1- atoms. There are a spread of Yb–F bond distances ranging from 1.47–2.11 Å. In the second Yb3+ site, Yb3+ is bonded in a 1-coordinate geometry to four F1- atoms. There are a spread of Yb–F bond distances ranging from 1.63–2.98 Å. In the third Yb3+ site, Yb3+ is bonded in a 1-coordinate geometry to five F1- atoms. There are a spread of Yb–F bond distances ranging from 1.65–2.81 Å. In the fourth Yb3+ site, Yb3+ is bonded in a 2-coordinate geometry to three F1- atoms. There are a spread of Yb–F bond distances ranging from 1.46–2.11 Å. In the fifth Yb3+ site, Yb3+ is bonded in a 1-coordinate geometry to four F1- atoms. There are a spread of Yb–F bond distances ranging from 1.63–2.93 Å. There are thirty-five inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to one Ca2+ atom. In the second F1- site, F1- is bonded in a distorted single-bond geometry to one Ca2+ atom. In the third F1- site, F1- is bonded in a distorted single-bond geometry to one Ca2+ atom. In the fourth F1- site, F1- is bonded in a distorted single-bond geometry to one Yb3+ atom. In the fifth F1- site, F1- is bonded in a distorted single-bond geometry to one Yb3+ atom. In the sixth F1- site, F1- is bonded in a single-bond geometry to one Yb3+ atom. In the seventh F1- site, F1- is bonded in a 12-coordinate geometry to three Ca2+, three Yb3+, and six F1- atoms. There are a spread of F–F bond distances ranging from 2.23–2.98 Å. In the eighth F1- site, F1- is bonded in a distorted L-shaped geometry to one Ca2+ and one Yb3+ atom. In the ninth F1- site, F1- is bonded in a distorted L-shaped geometry to two Ca2+ atoms. In the tenth F1- site, F1- is bonded in a 2-coordinate geometry to two Ca2+ atoms. In the eleventh F1- site, F1- is bonded in a 2-coordinate geometry to two Ca2+ and one F1- atom. In the twelfth F1- site, F1- is bonded in a distorted water-like geometry to two Ca2+ atoms. In the thirteenth F1- site, F1- is bonded in a distorted single-bond geometry to two Ca2+ atoms. In the fourteenth F1- site, F1- is bonded in a 2-coordinate geometry to two Yb3+ and one F1- atom. In the fifteenth F1- site, F1- is bonded in a distorted bent 120 degrees geometry to one Ca2+ and one Yb3+ atom. In the sixteenth F1- site, F1- is bonded in a distorted single-bond geometry to one Ca2+ and one F1- atom. The F–F bond length is 2.48 Å. In the seventeenth F1- site, F1- is bonded in a 1-coordinate geometry to one Ca2+ atom. In the eighteenth F1- site, F1- is bonded in a 2-coordinate geometry to two Yb3+ and one F1- atom. In the nineteenth F1- site, F1- is bonded in a 1-coordinate geometry to one Ca2+ atom. In the twentieth F1- site, F1- is bonded in a distorted single-bond geometry to one Ca2+ atom. In the twenty-first F1- site, F1- is bonded in a distorted bent 120 degrees geometry to one Ca2+ and one Yb3+ atom. In the twenty-second F1- site, F1- is bonded in a distorted single-bond geometry to one Ca2+ atom. In the twenty-third F1- site, F1- is bonded in a distorted water-like geometry to two Ca2+ atoms. In the twenty-fourth F1- site, F1- is bonded in a 1-coordinate geometry to three Ca2+ and three F1- atoms. The F–F bond length is 2.11 Å. In the twenty-fifth F1- site, F1- is bonded in a distorted L-shaped geometry to one Ca2+ and one Yb3+ atom. In the twenty-sixth F1- site, F1- is bonded in a distorted L-shaped geometry to two Ca2+ and one F1- atom. In the twenty-seventh F1- site, F1- is bonded in a distorted L-shaped geometry to one Ca2+ and one Yb3+ atom. In the twenty-eighth F1- site, F1- is bonded in a single-bond geometry to one Ca2+ atom. In the twenty-ninth F1- site, F1- is bonded in a distorted single-bond geometry to one Ca2+ and one Yb3+ atom. In the thirtieth F1- site, F1- is bonded in a distorted single-bond geometry to one Yb3+ atom. In the thirty-first F1- site, F1- is bonded in a distorted single-bond geometry to one Ca2+ atom. In the thirty-second F1- site, F1- is bonded in a 2-coordinate geometry to one Ca2+, one Yb3+, and one F1- atom. In the thirty-third F1- site, F1- is bonded in a distorted single-bond geometry to two Ca2+ atoms. In the thirty-fourth F1- site, F1- is bonded in a distorted single-bond geometry to one Ca2+ atom. In the thirty-fifth F1- site, F1- is bonded in a 2-coordinate geometry to one Ca2+, one Yb3+, and one F1- atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-06-05. Materials Data on Ca2YbF7 by Materials Project. https://doi.org/10.17188/1283265

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↗