Phonon spectrum attributes for the negative thermal expansion of MZrF6 (M = Ca, Mn–Ni, Zn)

The relative lattice constant of MZrF₆ (M = Ca, Mn–Ni, Zn) as a function of temperature in the FM (solid line) and AFM (dashed line) states. For comparison, the experimental results are reproduced as the inset in (b) from Hu et al. [J. Am. Chem. Soc., 2016, 138, 14530].