New Variants Of (110)-Oriented Layered Lead Bromide Perovskites, Templated By Formamidinium Or Pyrazolium

Four new hybrid lead(II) halide perovskites, gamma-(FA)(2)PbBr4, (FA)(1.5)(AA)(0.5)PbBr4, (PY)(GA)PbBr4 and (PY)(TZ)PbBr4 ((FA)=formamidinium, (AA)=acetamidinium, (PY)=pyrazolium, (GA)=guanidinium and (TZ)=1,2,3-triazolium), adopt (110)-oriented layered perovskite structures. While (PY) is found to template the formation of 'conventional' (110)-oriented structure types (i. e. containing staggered [PbBr4](infinity) layers), (FA) is shown to facilitate formation of much less common variants based 3 : 1 ordering of the interlayer species or 3x2 step-like corrugation of the perovskite-like layers themselves.