Engineering Papers⌕ Search

DOE OSTI · 1188647

Materials Data on Nd2Ti2O7 by Materials Project

Abstract

Nd2Ti2O7 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are eight inequivalent Nd3+ sites. In the first Nd3+ site, Nd3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Nd–O bond distances ranging from 2.35–2.95 Å. In the second Nd3+ site, Nd3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.35–2.59 Å. In the third Nd3+ site, Nd3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nd–O bond distances ranging from 2.33–2.45 Å. In the fourth Nd3+ site, Nd3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.41–2.67 Å. In the fifth Nd3+ site, Nd3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.41–2.67 Å. In the sixth Nd3+ site, Nd3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nd–O bond distances ranging from 2.33–2.45 Å. In the seventh Nd3+ site, Nd3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.35–2.59 Å. In the eighth Nd3+ site, Nd3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Nd–O bond distances ranging from 2.35–2.95 Å. There are eight inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 20–47°. There are a spread of Ti–O bond distances ranging from 1.82–2.39 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 20–42°. There are a spread of Ti–O bond distances ranging from 1.83–2.34 Å. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 24–47°. There are a spread of Ti–O bond distances ranging from 1.78–2.35 Å. In the fourth Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 24–42°. There are a spread of Ti–O bond distances ranging from 1.86–2.28 Å. In the fifth Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 24–42°. There are a spread of Ti–O bond distances ranging from 1.86–2.27 Å. In the sixth Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 24–47°. There are a spread of Ti–O bond distances ranging from 1.78–2.34 Å. In the seventh Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 20–42°. There are a spread of Ti–O bond distances ranging from 1.83–2.34 Å. In the eighth Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 20–47°. There are a spread of Ti–O bond distances ranging from 1.82–2.39 Å. There are twenty-six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to three Nd3+ and two equivalent Ti4+ atoms. In the second O2- site, O2- is bonded in a 5-coordinate geometry to three Nd3+ and two equivalent Ti4+ atoms. In the third O2- site, O2- is bonded in a distorted T-shaped geometry to one Nd3+ and two Ti4+ atoms. In the fourth O2- site, O2- is bonded to two Nd3+ and two Ti4+ atoms to form a mixture of distorted edge and corner-sharing ONd2Ti2 tetrahedra. In the fifth O2- site, O2- is bonded to two Nd3+ and two Ti4+ atoms to form a mixture of distorted edge and corner-sharing ONd2Ti2 tetrahedra. In the sixth O2- site, O2- is bonded to two Nd3+ and two Ti4+ atoms to form a mixture of distorted edge and corner-sharing ONd2Ti2 tetrahedra. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two Nd3+ and two Ti4+ atoms. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to two Nd3+ and two Ti4+ atoms. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to two Nd3+ and two Ti4+ atoms. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Nd3+ and two Ti4+ atoms. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to two Nd3+ and one Ti4+ atom. In the twelfth O2- site, O2- is bonded to three Nd3+ and one Ti4+ atom to form distorted ONd3Ti tetrahedra that share corners with seven ONd2Ti2 tetrahedra and edges with three ONd3Ti tetrahedra. In the thirteenth O2- site, O2- is bonded to three Nd3+ and one Ti4+ atom to form distorted ONd3Ti tetrahedra that share corners with five ONd2Ti2 tetrahedra and edges with four ONd3Ti tetrahedra. In the fourteenth O2- site, O2- is bonded to three Nd3+ and one Ti4+ atom to form distorted ONd3Ti tetrahedra that share corners with nine ONd2Ti2 tetrahedra and an edgeedge with one ONd3Ti tetrahedra. In the fifteenth O2- site, O2- is bonded to three Nd3+ and one Ti4+ atom to form distorted ONd3Ti tetrahedra that share corners with seven ONd2Ti2 tetrahedra and edges with three ONd3Ti tetrahedra. In the sixteenth O2- site, O2- is bonded to three Nd3+ and one Ti4+ atom to form distorted ONd3Ti tetrahedra that share corners with five ONd2Ti2 tetrahedra and edges with four ONd3Ti tetrahedra. In the seventeenth O2- site, O2- is bonded in a 1-coordinate geometry to two Nd3+ and one Ti4+ atom. In the eighteenth O2- site, O2- is bonded in a 1-coordinate geometry to three Nd3+ and two equivalent Ti4+ atoms. In the nineteenth O2- site, O2- is bonded in a 5-coordinate geometry to three Nd3+ and two equivalent Ti4+ atoms. In the twentieth O2- site, O2- is bonded to two Nd3+ and two Ti4+ atoms to form a mixture of distorted edge and corner-sharing ONd2Ti2 tetrahedra. In the twenty-first O2- site, O2- is bonded to two Nd3+ and two Ti4+ atoms to form a mixture of distorted edge and corner-sharing ONd2Ti2 tetrahedra. In the twenty-second O2- site, O2- is bonded in a 1-coordinate geometry to two Nd3+ and two Ti4+ atoms. In the twenty-third O2- site, O2- is bonded in a 1-coordinate geometry to two Nd3+ and two Ti4+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Nd3+ and two Ti4+ atoms. In the twenty-fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Nd3+ and two Ti4+ atoms. In the twenty-sixth O2- site, O2- is bonded to three Nd3+ and one Ti4+ atom to form distorted ONd3Ti tetrahedra that share corners with nine ONd2Ti2 tetrahedra and an edgeedge with one ONd3Ti tetrahedra.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-03. Materials Data on Nd2Ti2O7 by Materials Project. https://doi.org/10.17188/1188647

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↗