Search NASA⌕ Search

DOE OSTI · 1700965

Materials Data on Sr2Ca2IrO6 by Materials Project

Abstract

Sr2Ca2IrO6 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–2.82 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.52–2.79 Å. In the third Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.52–2.76 Å. There are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 pentagonal pyramids that share faces with two equivalent IrO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.34–2.39 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are two shorter (2.33 Å) and four longer (2.35 Å) Ca–O bond lengths. In the third Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.45–2.84 Å. Ir4+ is bonded to six O2- atoms to form IrO6 octahedra that share a faceface with one CaO6 pentagonal pyramid. There are a spread of Ir–O bond distances ranging from 2.04–2.09 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to two Sr2+, three Ca2+, and one Ir4+ atom to form distorted OSr2Ca3Ir octahedra that share corners with fourteen OSr2Ca3Ir octahedra, edges with two OSr3Ca2Ir octahedra, and faces with four OSr2Ca3Ir octahedra. The corner-sharing octahedra tilt angles range from 2–65°. In the second O2- site, O2- is bonded to three Sr2+, two Ca2+, and one Ir4+ atom to form distorted OSr3Ca2Ir octahedra that share corners with twelve OSr2Ca3Ir octahedra, edges with three OSr2Ca3Ir octahedra, and faces with five OSr3Ca2Ir octahedra. The corner-sharing octahedra tilt angles range from 16–65°. In the third O2- site, O2- is bonded to three Sr2+, two Ca2+, and one Ir4+ atom to form distorted OSr3Ca2Ir octahedra that share corners with twelve OSr2Ca3Ir octahedra, edges with four OSr3Ca2Ir octahedra, and faces with four OSr2Ca3Ir octahedra. The corner-sharing octahedra tilt angles range from 1–59°. In the fourth O2- site, O2- is bonded to three Sr2+, two Ca2+, and one Ir4+ atom to form distorted OSr3Ca2Ir octahedra that share corners with thirteen OSr2Ca3Ir octahedra, edges with three OSr2Ca3Ir octahedra, and faces with four OSr3Ca2Ir octahedra. The corner-sharing octahedra tilt angles range from 2–65°. In the fifth O2- site, O2- is bonded to three Sr2+, two Ca2+, and one Ir4+ atom to form distorted OSr3Ca2Ir octahedra that share corners with thirteen OSr2Ca3Ir octahedra, edges with four OSr3Ca2Ir octahedra, and faces with three OSr2Ca3Ir octahedra. The corner-sharing octahedra tilt angles range from 1–65°. In the sixth O2- site, O2- is bonded in a 6-coordinate geometry to two Sr2+, three Ca2+, and one Ir4+ atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-04-30. Materials Data on Sr2Ca2IrO6 by Materials Project. https://doi.org/10.17188/1700965

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↗