Large entropy change derived from the orbitally assisted three-centered two-electron {\sigma} bond formation in a metallic Li0.33VS2

TL;DR

This study reveals a large entropy change in metallic Li0.33VS2 due to orbitally assisted three-centered two-electron sigma bonds, suggesting potential for novel heat-storage materials with rapid thermal response.

Contribution

It demonstrates the formation of ribbon chains with three-centered two-electron sigma bonds in a metallic state, leading to a significant entropy change at the transition.

Findings

Large entropy change of 6.6 J/mol K observed at transition

Formation of ribbon chains with three-centered two-electron bonds

Metallic conductivity persists down to low temperatures

Abstract

We discuss herein the emergence of a large entropy change in metallic Li0.33VS2 derived from the orbitally assisted loose {\sigma} bond formation. Comprehensive structural studies based on synchrotron x-ray and neutron diffraction analyses clarify the fabrication of ribbon chains at 375 K, consisting of multiple three-centered two-electron {\sigma} bonds based on the viewpoint of local chemical bonding. Although the metallic conductivity persists down to the lowest temperature measured, exceptionally large entropy change as a metal, as much as {\Delta}S = 6.6 J/mol K, appears at the transition. Emergence of a large entropy change in a metallic state expects us the possible novel functional materials, such as a heat-storage material with rapid thermal response.