  The influence of zinc ions on the thermochromic properties of polycrystalline
Cu$_{1-x}$Zn$_x$MoO$_4$ ($x$=0.10, 0.50, 0.90) solid solutions was studied by
X-ray absorption spectroscopy at the Cu, Zn and Mo K-edges. Detailed structural
information on the local environment of metal ions was obtained from the
simultaneous analysis of EXAFS spectra measured at three metal absorption edges
using the reverse Monte Carlo method. Thermochromic phase transition with the
hysteretic behaviour between $\alpha$ and $\gamma$ phases was observed in
Cu$_{0.90}$Zn$_{0.10}$MoO$_4$ solid solution. It was found that the local
environment of molybdenum ions is most susceptible to the substitution of
copper for zinc and, upon cooling, transforms from tetrahedral MoO$_4$ to
distorted octahedral MoO$_6$.
