Crystal structure, Hirshfeld surfaces analysis, infrared-raman, and UV spectra of octylenediammonium pentachlorobismuthate NH3(CH2)8NH3BiCl5

•The NH3(CH2)8NH3BiCl5 crystal structure and Hirshfeld surfaces packing are determined.•The IR and Raman spectra of this compound are studied based on theoretical group analyses.•The DSC, and optical analyses of NH3(CH2)8NH3BiCl5 are performed. NH3(CH2)8NH3BiCl5 compound crystallized at 296 K in the monoclinic system, with the space group P21/c (Z = 4), and parametrs: a = 12.5130(13) Å, b = 12.3251(9) Å, c = 12.0396(15) Å, β=104.802(8)°. Its crystal structure is consisted of organic cations +NH3(CH2)8NH3+ linked to Bi2Cl104- dimers, which are composed of two distorted octahedral BiCl63− sharing an edge. The anions and cations are linked by weak hydrogen N-H…Cl bonding. The 3D Hirshfeld surface analysis is used in the construction of the 2D fingerprint plots, to analyze the significant intermolecular interactions in the crystal network, and to determine the contribution of such interactions in the crystal structure. DSC analysis showed that this compound presents two irreversible phase transitions at high temperatures near 198 and 218 °C, observed at first and second heating. Characteristic bands observed at room temperature in Infrared (400-4000 cm−1) and Raman (50–3500 cm−1) spectra are assigned and interpreted based on factor group analysis for +NH3(CH2)8NH3+ cations and Bi2Cl104− anions, linked together by hydrogen bonding. The compound presents indigo-blue photoluminescence (PL) with a broad emission signal at 475 nm (2.609 eV) when it was excited with λmax excitation = 400 nm (3.099 eV), which suggests potential applications in UV detection and optical materials for this compound.