For Bi 2 SeO 2 the comparisons suggest the calculations may overestimate the measured κ latt at low temperature but that the agreement between the predictions and measurements improve at higher temperature. The measured room-temperature which are 40-60% smaller than our predicted average 2.6 W m -1 K -1 but comparable to the smaller predicted κ zz = 1.5 W m -1 K -1 along the c axis. The agreement improves at higher temperature, such that the measurements of κ latt = 0.7 -0.8 W m -1 K -1 at ∼ 825 K are around 15-25% smaller than our average of 0.94 W m -1 K -1 .