Illustrating Extreme Negative Linear Compressibility in Thermosalient Molecular Crystals

Mladineo, Bruno; Klaser, Teodoro; Ende, Martin; Popović, Jasminka; Lončarić, Ivor; Skoko, Željko (2025) Illustrating Extreme Negative Linear Compressibility in Thermosalient Molecular Crystals. Crystal Growth & Design . ISSN 1528-7483

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Abstract

We report a high-pressure single-crystal X-ray diffraction study of the thermosalient molecular crystal N’-2-propylidene-4hydroxybenzohydrazide. We find that it features one of the largest negative linear compressibilities recorded, with a coefficient of −39 TPa–1. With increasing pressure, it converts to a positive linear compressibility and at even higher pressures again to a negative linear compressibility. This switchable behavior arises from the pressure-induced straightening of the hydrogen-bonded zigzag chains, which is eventually counteracted by direct bond compression. To capture this mechanism, we trained a machine-learning interatomic potential and performed quasi-harmonic free-energy calculations, thereby obtaining atomistic insight across the whole pressure range. These findings broaden the still-scarce catalog of organic crystals that combine thermosalient activity with experimentally verified, pressure-tunable NLC.

Item Type:	Article
Uncontrolled Keywords:	negative linear compressibility; machine learning interatomic potential; high-pressure x-ray diffraction
Subjects:	NATURAL SCIENCES > Physics NATURAL SCIENCES > Physics > Condensed Matter Physics
Divisions:	Division of Materials Physics Theoretical Physics Division
Projects:	Project title Project leader Project code Project type Povećanje prostorne i vremenske skale modeliranja materijala iz prvih principa pomoću strojnog učenja-ExtMatModelML Ivor Lončarić UIP-2020-02-5675 HRZZ
Depositing User:	Ivor Lončarić
Date Deposited:	23 Sep 2025 13:16
URI:	http://fulir.irb.hr/id/eprint/10016
DOI:	10.1021/acs.cgd.5c01043

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