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1. Electron-density analysis of halide...halide through-space magnetic exchange

   https://doi.org/10.1107/S1600576725000536  

   Scatena, Rebecca; Manson, Zachary E; Villa, Danielle Y; Manson, Jamie L; Allan, David R; Goddard, Paul A; Johnson, Roger D (April 2025, Journal of Applied Crystallography)

   We present a combined experimental and density functional theory study that characterizes the charge and spin density in NiX₂(3,5-lutidine)₄(X= Cl, Br and I). In this material, magnetic exchange interactions occur via Ni²⁺–halide...halide–Ni²⁺pathways, forming one-dimensional chains. We find evidence for weak halide...halide covalency in the iodine system, which is greatly reduced whenX= Br and is absent forX= Cl; this is consistent with the reported `switching-on' of magnetic exchange in the larger-halide cases. Our results are benchmarked against density functional theory calculations on [NiHF₂(pyrazine)₂]SbF₆, in which the primary magnetic exchange is mediated by F–H–F bridging ligands. This comparison indicates that, despite the largely depleted charge density found at the centre of halide...halide bonds, these through-space interactions can support strong magnetic exchange gated by weak covalency and enhanced by significant electron density overlapping that of the transition metal centres. 

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2. Halide Ion Microhydration: Structure, Energetics, and Spectroscopy of Small Halide–Water Clusters

   https://doi.org/10.1021/acs.jpca.9b00816  

   Bajaj, Pushp; Riera, Marc; Lin, Jason K.; Mendoza Montijo, Yaira E.; Gazca, Jessica; Paesani, Francesco (March 2019, The Journal of Physical Chemistry A)
3. Effects of size mismatch of halide ions on the phase stability of mixed halide perovskites

   https://doi.org/10.1088/1402-4896/ad1adb  

   Yang, Fuqian (January 2024, Physica Scripta)

   Abstract The phase stability of mixed halide perovskites plays a vital role in the performance and reliability of perovskite-based devices and systems. In this work, we incorporate the contribution of the strain energy due to the size mismatch of halideions in Gibbs free energy for the analysis of the phase stability of mixed halide perovskites. Analytical expressions of the chemical potentials of halide ions in mixed halide perovskites are derived and used to determine the critical atomic fractions of halide ions for the presence of spinodal decomposition (phase instability). The numerical analysis of CH₃NH₃PbI_xBr_3-xmixed halide perovskite reveals the important role of the mismatch strain from halide ions in controlling the phase instability of mixed halide perovskite, i.e., increasing the mismatch strain widens the range ofxfor the phase separation of mixed halide perovskites. To mitigate the phase instability associated with the strain energy from intrinsic size mismatch and/or light-induced expansion, strain and/or field engineering, such as high pressure, can be likely applied to introduce strain and/or field gradient to counterbalance the strain gradient by the mismatch strain and/or light-induced expansion. 

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4. Photo-induced halide redistribution in 2D halide perovskite lateral heterostructures

   https://doi.org/10.1016/j.joule.2023.08.003  

   Luo, Yanqi; Zhang, Shuchen; Chen, Jia-Shiang; Ma, Xuedan; Ma, Ke; Deng, Junjing; Jiang, Yi; Li, Luxi; Lai, Barry; Chen, Si; et al (October 2023, Joule)
5. The halogen chemistry of halide perovskites

   https://doi.org/10.1016/j.trechm.2021.12.002  

   Matheu, Roc; Vigil, Julian A.; Crace, Ethan J.; Karunadasa, Hemamala I. (March 2022, Trends in Chemistry)