Engineering Papers⌕ Search

DOE OSTI · 1713818

Materials Data on Ca5(Si2Au3)2 by Materials Project

Abstract

Ca5(Au3Si2)2 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are ten inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 12-coordinate geometry to nine Au+0.33- and three equivalent Si2- atoms. There are a spread of Ca–Au bond distances ranging from 3.05–3.37 Å. There are one shorter (3.13 Å) and two longer (3.45 Å) Ca–Si bond lengths. In the second Ca2+ site, Ca2+ is bonded in a 12-coordinate geometry to six Au+0.33- and six Si2- atoms. There are a spread of Ca–Au bond distances ranging from 3.05–3.17 Å. There are a spread of Ca–Si bond distances ranging from 3.12–3.40 Å. In the third Ca2+ site, Ca2+ is bonded in a 12-coordinate geometry to eight Au+0.33- and four Si2- atoms. There are a spread of Ca–Au bond distances ranging from 3.02–3.28 Å. There are a spread of Ca–Si bond distances ranging from 3.20–3.46 Å. In the fourth Ca2+ site, Ca2+ is bonded in a 12-coordinate geometry to seven Au+0.33- and five Si2- atoms. There are a spread of Ca–Au bond distances ranging from 3.06–3.23 Å. There are a spread of Ca–Si bond distances ranging from 3.11–3.38 Å. In the fifth Ca2+ site, Ca2+ is bonded in a 12-coordinate geometry to six Au+0.33- and six Si2- atoms. There are a spread of Ca–Au bond distances ranging from 3.06–3.17 Å. There are a spread of Ca–Si bond distances ranging from 3.13–3.39 Å. In the sixth Ca2+ site, Ca2+ is bonded in a 12-coordinate geometry to nine Au+0.33- and three Si2- atoms. There are a spread of Ca–Au bond distances ranging from 3.03–3.60 Å. There are one shorter (3.16 Å) and two longer (3.19 Å) Ca–Si bond lengths. In the seventh Ca2+ site, Ca2+ is bonded in a 12-coordinate geometry to six Au+0.33- and six Si2- atoms. There are a spread of Ca–Au bond distances ranging from 3.14–3.37 Å. There are a spread of Ca–Si bond distances ranging from 3.02–3.23 Å. In the eighth Ca2+ site, Ca2+ is bonded in a 11-coordinate geometry to eight Au+0.33- and three Si2- atoms. There are a spread of Ca–Au bond distances ranging from 3.06–3.25 Å. There are two shorter (3.19 Å) and one longer (3.25 Å) Ca–Si bond lengths. In the ninth Ca2+ site, Ca2+ is bonded in a 12-coordinate geometry to six Au+0.33- and six Si2- atoms. There are a spread of Ca–Au bond distances ranging from 3.16–3.34 Å. There are a spread of Ca–Si bond distances ranging from 3.05–3.26 Å. In the tenth Ca2+ site, Ca2+ is bonded in a 12-coordinate geometry to six Au+0.33- and six Si2- atoms. There are a spread of Ca–Au bond distances ranging from 3.16–3.33 Å. There are a spread of Ca–Si bond distances ranging from 3.03–3.27 Å. There are twelve inequivalent Au+0.33- sites. In the first Au+0.33- site, Au+0.33- is bonded in a 10-coordinate geometry to six Ca2+, three Au+0.33-, and one Si2- atom. There are two shorter (2.81 Å) and one longer (2.86 Å) Au–Au bond lengths. The Au–Si bond length is 2.64 Å. In the second Au+0.33- site, Au+0.33- is bonded in a 10-coordinate geometry to six Ca2+, three Au+0.33-, and one Si2- atom. There are two shorter (2.79 Å) and one longer (2.90 Å) Au–Au bond lengths. The Au–Si bond length is 2.66 Å. In the third Au+0.33- site, Au+0.33- is bonded in a 10-coordinate geometry to six Ca2+, one Au+0.33-, and three Si2- atoms. The Au–Au bond length is 3.16 Å. There are two shorter (2.62 Å) and one longer (2.68 Å) Au–Si bond lengths. In the fourth Au+0.33- site, Au+0.33- is bonded in a 10-coordinate geometry to six Ca2+, one Au+0.33-, and three Si2- atoms. The Au–Au bond length is 3.19 Å. There are two shorter (2.61 Å) and one longer (2.68 Å) Au–Si bond lengths. In the fifth Au+0.33- site, Au+0.33- is bonded in a 10-coordinate geometry to six Ca2+, one Au+0.33-, and three Si2- atoms. The Au–Au bond length is 3.12 Å. There are two shorter (2.61 Å) and one longer (2.65 Å) Au–Si bond lengths. In the sixth Au+0.33- site, Au+0.33- is bonded in a 1-coordinate geometry to five Ca2+, three Au+0.33-, and one Si2- atom. The Au–Au bond length is 3.09 Å. The Au–Si bond length is 2.48 Å. In the seventh Au+0.33- site, Au+0.33- is bonded in a 1-coordinate geometry to six Ca2+, three Au+0.33-, and one Si2- atom. The Au–Au bond length is 3.20 Å. The Au–Si bond length is 2.51 Å. In the eighth Au+0.33- site, Au+0.33- is bonded in a 3-coordinate geometry to six Ca2+, one Au+0.33-, and three Si2- atoms. There are two shorter (2.56 Å) and one longer (2.66 Å) Au–Si bond lengths. In the ninth Au+0.33- site, Au+0.33- is bonded in a 10-coordinate geometry to six Ca2+, one Au+0.33-, and three Si2- atoms. There are two shorter (2.61 Å) and one longer (2.69 Å) Au–Si bond lengths. In the tenth Au+0.33- site, Au+0.33- is bonded in a 10-coordinate geometry to six Ca2+, one Au+0.33-, and three Si2- atoms. There are two shorter (2.61 Å) and one longer (2.67 Å) Au–Si bond lengths. In the eleventh Au+0.33- site, Au+0.33- is bonded in a 10-coordinate geometry to six Ca2+, two Au+0.33-, and two equivalent Si2- atoms. Both Au–Si bond lengths are 2.54 Å. In the twelfth Au+0.33- site, Au+0.33- is bonded in a 2-coordinate geometry to six Ca2+, two Au+0.33-, and two equivalent Si2- atoms. Both Au–Si bond lengths are 2.47 Å. There are eight inequivalent Si2- sites. In the first Si2- site, Si2- is bonded in a 4-coordinate geometry to six Ca2+ and four Au+0.33- atoms. In the second Si2- site, Si2- is bonded in a 3-coordinate geometry to six Ca2+, three Au+0.33-, and one Si2- atom. The Si–Si bond length is 2.56 Å. In the third Si2- site, Si2- is bonded in a 3-coordinate geometry to six Ca2+, three Au+0.33-, and one Si2- atom. The Si–Si bond length is 2.55 Å. In the fourth Si2- site, Si2- is bonded in a 3-coordinate geometry to six Ca2+, three Au+0.33-, and one Si2- atom. The Si–Si bond length is 2.53 Å. In the fifth Si2- site, Si2- is bonded in a 4-coordinate geometry to six Ca2+ and four Au+0.33- atoms. In the sixth Si2- site, Si2- is bonded in a 3-coordinate geometry to six Ca2+, three Au+0.33-, and one Si2- atom. In the seventh Si2- site, Si2- is bonded in a 3-coordinate geometry to six Ca2+, three Au+0.33-, and one Si2- atom. In the eighth Si2- site, Si2- is bonded in a 3-coordinate geometry to six Ca2+, three Au+0.33-, and one Si2- atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-04-30. Materials Data on Ca5(Si2Au3)2 by Materials Project. https://doi.org/10.17188/1713818

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↗