Observation of grey cesium tin bromide with unusual phase transition

Abstract

A new grey colour polymorph of CsSnBr3 with non-cubic phase at 295(±1) K is observed. Contrary to black and yellow polymorphs, it seems that not only the β-α transition at 292 K shifted to 304 K but also the new β 3-phase with second-order phase transition (β 2-β 3) can be seen in this new grey polymorph. The structural refinement shows the monoclinic phase with holohedry for β 3-CsSnBr3 against the group-subgroup theory. However, the parameters and are suggesting pseudo-tetragonality for β 3-CsSnBr3 Copyright © 2023 EPLA.