Search NASA⌕ Search

DOE OSTI · 1313054

Materials Data on Ca3Tl2O6 by Materials Project

Abstract

Tl2Ca3O6 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to seven O2- atoms to form distorted CaO7 pentagonal bipyramids that share corners with two equivalent TlO6 octahedra, corners with six CaO6 octahedra, a cornercorner with one CaO7 pentagonal bipyramid, edges with three CaO6 octahedra, edges with four equivalent TlO6 octahedra, and faces with two equivalent CaO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 21–72°. There are a spread of Ca–O bond distances ranging from 2.47–2.71 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with four CaO6 octahedra, corners with two equivalent CaO7 pentagonal bipyramids, edges with three equivalent CaO6 octahedra, edges with six TlO6 octahedra, and an edgeedge with one CaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 0–65°. There are a spread of Ca–O bond distances ranging from 2.35–2.46 Å. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with two equivalent TlO6 octahedra, corners with four equivalent CaO7 pentagonal bipyramids, edges with two equivalent CaO6 octahedra, edges with four TlO6 octahedra, and edges with two equivalent CaO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 8–65°. There are a spread of Ca–O bond distances ranging from 2.33–2.52 Å. There are two inequivalent Tl3+ sites. In the first Tl3+ site, Tl3+ is bonded to six O2- atoms to form distorted TlO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with three TlO6 octahedra, corners with two equivalent CaO7 pentagonal bipyramids, edges with three TlO6 octahedra, and edges with six CaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–59°. There are a spread of Tl–O bond distances ranging from 2.25–2.68 Å. In the second Tl3+ site, Tl3+ is bonded to six O2- atoms to form TlO6 octahedra that share corners with four TlO6 octahedra, edges with four CaO6 octahedra, edges with four TlO6 octahedra, and edges with four equivalent CaO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Tl–O bond distances ranging from 2.13–2.54 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Ca2+ and four equivalent Tl3+ atoms to form OCa2Tl4 octahedra that share corners with four equivalent OCa2Tl4 octahedra, corners with four equivalent OCa4Tl trigonal bipyramids, edges with four OCa2Tl4 octahedra, and edges with eight OCa4Tl square pyramids. The corner-sharing octahedral tilt angles are 3°. In the second O2- site, O2- is bonded to four Ca2+ and one Tl3+ atom to form distorted OCa4Tl square pyramids that share corners with two equivalent OCa4Tl2 octahedra, corners with three equivalent OCa4Tl square pyramids, corners with two equivalent OCa2Tl2 tetrahedra, corners with two equivalent OCa4Tl trigonal bipyramids, edges with five OCa2Tl4 octahedra, edges with three OCa4Tl square pyramids, and an edgeedge with one OCa4Tl trigonal bipyramid. The corner-sharing octahedral tilt angles are 6°. In the third O2- site, O2- is bonded to four equivalent Ca2+ and two equivalent Tl3+ atoms to form OCa4Tl2 octahedra that share corners with four equivalent OCa4Tl square pyramids, corners with two equivalent OCa4Tl trigonal bipyramids, edges with six OCa2Tl4 octahedra, edges with two equivalent OCa4Tl square pyramids, and edges with four equivalent OCa2Tl2 tetrahedra. In the fourth O2- site, O2- is bonded to four Ca2+ and one Tl3+ atom to form distorted OCa4Tl square pyramids that share corners with three equivalent OCa4Tl square pyramids, corners with two equivalent OCa2Tl2 tetrahedra, corners with four equivalent OCa4Tl trigonal bipyramids, edges with four OCa2Tl4 octahedra, edges with three OCa4Tl square pyramids, and edges with two equivalent OCa4Tl trigonal bipyramids. In the fifth O2- site, O2- is bonded to four Ca2+ and one Tl3+ atom to form distorted OCa4Tl trigonal bipyramids that share corners with three OCa2Tl4 octahedra, corners with six OCa4Tl square pyramids, corners with four equivalent OCa2Tl2 tetrahedra, edges with two equivalent OCa2Tl4 octahedra, edges with three OCa4Tl square pyramids, and edges with two equivalent OCa4Tl trigonal bipyramids. The corner-sharing octahedra tilt angles range from 12–43°. In the sixth O2- site, O2- is bonded to two Ca2+ and two equivalent Tl3+ atoms to form OCa2Tl2 tetrahedra that share corners with four equivalent OCa2Tl4 octahedra, corners with four OCa4Tl square pyramids, corners with two equivalent OCa2Tl2 tetrahedra, corners with four equivalent OCa4Tl trigonal bipyramids, and edges with three OCa2Tl4 octahedra. The corner-sharing octahedra tilt angles range from 3–14°. In the seventh O2- site, O2- is bonded to two Ca2+ and four Tl3+ atoms to form OCa2Tl4 octahedra that share corners with two equivalent OCa2Tl4 octahedra, corners with four equivalent OCa2Tl2 tetrahedra, edges with five OCa2Tl4 octahedra, edges with four OCa4Tl square pyramids, an edgeedge with one OCa2Tl2 tetrahedra, and edges with two equivalent OCa4Tl trigonal bipyramids. The corner-sharing octahedral tilt angles are 3°.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-04-30. Materials Data on Ca3Tl2O6 by Materials Project. https://doi.org/10.17188/1313054

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↗