Low-Frequency Phonon Driven Negative Thermal Expansion in Cubic GaFe(CN)6 Prussian Blue Analogues

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

34 Scopus Citations
View graph of relations

Author(s)

  • Qilong Gao
  • Naike Shi
  • Qiang Sun
  • Andrea Sanson
  • Ruggero Milazzo
  • Alberto Carnera
  • He Zhu
  • Saul H. Lapidus
  • Qingzhen Huang
  • Jun Chen
  • Xianran Xing

Detail(s)

Original languageEnglish
Pages (from-to)10918-10924
Journal / PublicationInorganic Chemistry
Volume57
Issue number17
Publication statusPublished - 4 Sept 2018
Externally publishedYes

Abstract

The understanding of the negative thermal expansion (NTE) mechanism is vital not only for the development of new NTE compounds but also for effectively controlling thermal expansion. Here, we report an interesting isotropic NTE property in cubic GaFe(CN)6 Prussian blue analogues (αl = -3.95 × 10-6 K-1, 100-475 K), which is a new example to understand the complex NTE mechanism. A combined study of synchrotron X-ray diffraction, X-ray total scattering, X-ray absorption fine structure, neutron powder diffraction, and density functional theory calculations shows that the NTE of GaFe(CN)6 originates from the low-frequency phonons (< ∼100 cm-1), which are directly related to the transverse vibrations of the atomic -Ga-N ≡C-Fe- chains. Both the Ga-N and Fe-C chemical bonds are much softer to bend than to stretch. The direct evidence that transverse vibrational contribution to the NTE of GaFe(CN)6 is dominated by N, instead of C atoms, is illustrated. It is interesting to find that the polyhedra of GaFe(CN)6 are not rigid, which is a starting assumption in some models describing the NTE properties of other systems. The NTE mechanism can be vividly described by the "guitar-string" effect, which would be the common feature for the NTE property of many open-framework functional materials, such as Prussian blue analogues, oxides, cyanides, metal-organic frameworks, and zeolites.

Bibliographic Note

Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to lbscholars@cityu.edu.hk.

Citation Format(s)

Low-Frequency Phonon Driven Negative Thermal Expansion in Cubic GaFe(CN)6 Prussian Blue Analogues. / Gao, Qilong; Shi, Naike; Sun, Qiang et al.
In: Inorganic Chemistry, Vol. 57, No. 17, 04.09.2018, p. 10918-10924.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review