Search NASA⌕ Search

DOE OSTI · 1672643

Materials Data on Mg8SiW9O49 by Materials Project

Abstract

MgO6Mg7W9SiO43 crystallizes in the monoclinic Cc space group. The structure is three-dimensional and consists of four magnesium;dihydroxide;tetrahydrate molecules and one Mg7W9SiO43 framework. In the Mg7W9SiO43 framework, there are three inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share a cornercorner with one SiO4 tetrahedra and edges with two equivalent MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.13 Å. In the second Mg site, Mg is bonded to five O atoms to form distorted corner-sharing MgO5 trigonal bipyramids. There are a spread of Mg–O bond distances ranging from 1.98–2.14 Å. In the third Mg site, Mg is bonded in a distorted hexagonal planar geometry to six O atoms. There are three shorter (2.02 Å) and three longer (2.05 Å) Mg–O bond lengths. There are three inequivalent W sites. In the first W site, W is bonded in a 6-coordinate geometry to six O atoms. There are a spread of W–O bond distances ranging from 1.78–2.42 Å. In the second W site, W is bonded in a 6-coordinate geometry to six O atoms. There are a spread of W–O bond distances ranging from 1.78–2.42 Å. In the third W site, W is bonded in a 6-coordinate geometry to six O atoms. There are a spread of W–O bond distances ranging from 1.78–2.37 Å. Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 58°. There is one shorter (1.63 Å) and three longer (1.67 Å) Si–O bond length. There are forty-one inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–Mg bond length is 1.98 Å. In the second O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–Mg bond length is 1.98 Å. The O–W bond length is 1.78 Å. In the third O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–W bond length is 1.78 Å. In the fourth O site, O is bonded in a bent 120 degrees geometry to two W atoms. In the fifth O site, O is bonded in a bent 120 degrees geometry to two W atoms. There is one shorter (1.92 Å) and one longer (2.01 Å) O–W bond length. In the sixth O site, O is bonded in a bent 120 degrees geometry to two W atoms. There is one shorter (1.92 Å) and one longer (2.01 Å) O–W bond length. In the seventh O site, O is bonded in a T-shaped geometry to three Mg atoms. In the eighth O site, O is bonded in a T-shaped geometry to three Mg atoms. In the ninth O site, O is bonded in a T-shaped geometry to three Mg atoms. There are one shorter (2.13 Å) and one longer (2.14 Å) O–Mg bond lengths. In the tenth O site, O is bonded in a single-bond geometry to one Mg atom. In the eleventh O site, O is bonded in a single-bond geometry to one Mg atom. The O–Mg bond length is 2.13 Å. In the twelfth O site, O is bonded in a distorted single-bond geometry to three W and one Si atom. In the thirteenth O site, O is bonded in a distorted single-bond geometry to three W and one Si atom. There are one shorter (2.37 Å) and two longer (2.42 Å) O–W bond lengths. In the fourteenth O site, O is bonded in a distorted single-bond geometry to three W and one Si atom. There are one shorter (2.37 Å) and two longer (2.42 Å) O–W bond lengths. In the fifteenth O site, O is bonded in a distorted trigonal pyramidal geometry to three equivalent Mg and one Si atom. In the sixteenth O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–Mg bond length is 2.01 Å. The O–W bond length is 1.78 Å. In the seventeenth O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. In the eighteenth O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–Mg bond length is 2.01 Å. The O–W bond length is 1.78 Å. In the nineteenth O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–Mg bond length is 2.01 Å. In the twentieth O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–W bond length is 1.78 Å. In the twenty-first O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–Mg bond length is 2.01 Å. The O–W bond length is 1.78 Å. In the twenty-second O site, O is bonded in a bent 120 degrees geometry to two W atoms. In the twenty-third O site, O is bonded in a bent 120 degrees geometry to two W atoms. Both O–W bond lengths are 2.03 Å. In the twenty-fourth O site, O is bonded in a bent 120 degrees geometry to two W atoms. Both O–W bond lengths are 2.03 Å. In the twenty-fifth O site, O is bonded in a bent 150 degrees geometry to two W atoms. The O–W bond length is 1.93 Å. In the twenty-sixth O site, O is bonded in a bent 150 degrees geometry to two W atoms. Both O–W bond lengths are 1.93 Å. In the twenty-seventh O site, O is bonded in a bent 150 degrees geometry to two W atoms. The O–W bond length is 1.93 Å. In the twenty-eighth O site, O is bonded in a bent 120 degrees geometry to two W atoms. In the twenty-ninth O site, O is bonded in a bent 120 degrees geometry to two W atoms. There is one shorter (1.92 Å) and one longer (2.01 Å) O–W bond length. In the thirtieth O site, O is bonded in a bent 120 degrees geometry to two W atoms. There is one shorter (1.92 Å) and one longer (2.01 Å) O–W bond length. In the thirty-first O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–Mg bond length is 2.03 Å. In the thirty-second O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–Mg bond length is 2.03 Å. The O–W bond length is 1.82 Å. In the thirty-third O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–W bond length is 1.82 Å. In the thirty-fourth O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. In the thirty-fifth O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–Mg bond length is 2.03 Å. The O–W bond length is 1.82 Å. In the thirty-sixth O site, O is bonded in a bent 150 degrees geometry to one Mg and one W atom. The O–Mg bond length is 2.03 Å. The O–W bond length is 1.82 Å. In the thirty-seventh O site, O is bonded in a trigonal non-coplanar geometry to three Mg atoms. In the thirty-eighth O site, O is bonded in a trigonal non-coplanar geometry to three Mg atoms. Both O–Mg bond lengths are 2.12 Å. In the thirty-ninth O site, O is bonded in a trigonal non-coplanar geometry to three Mg atoms. In the fortieth O site, O is bonded in a bent 150 degrees geometry to two equivalent W atoms. In the forty-first O site, O is bonded in a bent 150 degrees geometry to two equivalent W atoms.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-02. Materials Data on Mg8SiW9O49 by Materials Project. https://doi.org/10.17188/1672643

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↗