Fig. 2: Structural characteristics of chiral MHPs.

a–e Schematic single-crystal X-ray structures of [S-4-NO₂-MBA]₂PbBr₄.H₂O (a), [R-4-Cl-MBA]₂PbBr₄ (b), [S-2-Me-BuA]₂PbBr₄ (c), [S-4-NH₃-MBA]PbI₄ (d), and [S-MHA]₂PbI₄ (e). In each case, all H atoms except the one on the chiral carbon stereocenter are omitted for clarity. f–j In-plane views of perovskite layers corresponding to (a–e) showing the equatorial Pb–X–Pb bond angles (\(\beta\)). Axial X atoms are omitted for clarity. The two distinct equatorial Br atoms associated with widely disparate \(\beta\) angles in (f, g) are distinguished by shaded and solid spheres. The dashed rectangles differentiate the individual rows comprised of the same type of equatorial Br atoms from the rows comprising alternating types of equatorial Br atoms, highlighting the local geometry fluctuation along one of the in-plane directions. In (h–j), the two unique equatorial X atoms are geometrically nominally equivalent with similar \(\beta\) angles. Gray, brown, purple, red, green, blue, black, and pink spheres denote Pb, Br, I, O, Cl, N, C, and H atoms, respectively.