All nine Li7 garnets were first analysed for phase purity at room temperature, and all were indexed on a tetragonal garnet cell (I41/acd). Variable temperature X-Ray diffraction (VTXRD) data were subsequently collected for these garnets up to 1000°C. This is beyond the common phase transition temperature (~700°C) but was required to reach the phase transition temperature for the Nb/Ta tetragonal phases. This caused some degradation for some systems; hence the complete reversal of the phase transition was not observed.