The electrical conductivity of K2MoO4-MnMoO4-Zr(MoO4)(2) molybdates was mea
sured as a function of temperature, These compounds exhibit mixed conductiv
ity, which becomes purely ionic at high temperatures, The breaks observed i
n the Arrhenius plots of conductivity are due to the polymorphic transforma
tions of the corresponding molybdates.