To the best of our knowledge the κ latt of π SnS and SnSe have not been measured. We previously predicted a room-temperature lattice thermal conductivity of 0.13 W m -1 K -1 for π SnS. However, this calculation did not account for intraband tunneling and is equivalent to the κ p obtained in the present study. Using the data from Ref. , we obtain a κ w of 0.32 W m -1 K -1 and a total κ latt of 0.45 W m -1 K -1 (Fig. † ), which is 26% lower than predicted in the present work. One possible explanation for this discrepancy is the use of a dispersion correction in the present calculations, which has a small but noticeable effect on the dis- persion (Fig. ). This could be due in part to the ∼3.3% smaller equilibrium volume predicted with the dispersion correction, since the phonon frequencies, and, by extension, κ latt , can be sensitive to the volume. Related to this point, we also note that the anharmonicity in the π phases may be indicative of large thermal expansion, which could have a significant impact on the κ latt . However, the high computational cost of calculating the thirdorder force constants for the π phases means it is not feasible to account for this in the present calculations.