ZrO2 is an ionic conductor used in automobile engine control systems. At 800oC the mobility of Zr4+ is 0.01m2/V.sec, and of O2- it is 0.04 m2/V.sec., there are 4.5 x 1017 mobile Zr4+ ions/m3, and 2.0 x 1018 mobile O2- ions/m3. What is the conductivity of ZrO2 at this temperature, in S.m-1? 2. Relevant equations σ=ni*|e|*μe + ni*|e|*μh 3. The attempt at a solution (.01)(4.5E17)(1.6E-19)+(.04)(2E18)(1.6E-19)=0.01352 (ions*C)/(mVs)~>(ions)/(Ωm) Am I supposed to cancel out ions somehow. I am confused about how this is supposed to work however. I think I am missing a few fundamental concepts here.