Negative thermal expansion in the Prussian Blue analog Zn3[Fe(CN)6]2: X-ray diffraction and neutron vibrational studies

TL;DR

This study investigates the negative thermal expansion property of Zn3[Fe(CN)6]2 using X-ray diffraction and neutron scattering, revealing a significant NTE coefficient and detailed vibrational modes.

Contribution

It provides the first detailed analysis of NTE behavior and vibrational spectra in Zn3[Fe(CN)6]2, combining X-ray and neutron studies.

Findings

NTE coefficient of -31.1 x 10^-6 K^-1

Identification of vibrational modes below 800 cm^-1

Confirmation of NTE behavior through X-ray data

Abstract

The cubic Prussian Blue (PB) analog, Zn3 [Fe(CN)6]2, has been studied by X-ray powder diffraction and inelastic neutron scattering (INS). X-ray data collected at 300 and 84 K revealed negative thermal expansion (NTE) behaviour for this material. The NTE coefficient was found to be -31.1 x 10-6 K-1. The neutron vibrational spectrum for Zn3[Fe(CN)6]2.xH2O, was studied in detail. The INS spectrum showed well-defined, well-separated bands corresponding to the stretching of and deformation modes of the Fe and Zn octahedra, all below 800 cm-1.