Department of Chemistry2024-11-1020140038-109810.1016/j.ssc.2014.02.0172-s2.0-84896449080http://dx.doi.org/10.1016/j.ssc.2014.02.017https://hdl.handle.net/20.500.14288/16132The temperature-induced solid-solid transformation of Rb-2[PH] and Cs-2[PH] is characterized from both experiment and theory. Neutron diffraction, IR-spectroscopy and ab-initio molecular dynamics simulations reveal an asymmetric shift of the lattice constants at 80 K. The molecular mechanism of the structural transformation as identified from IR-spectroscopy and ab-initio molecular dynamics simulations is closely connected to the orientation of the [PH](2-) moieties which undergo a partial order-disorder phase transition.PhysicsCondensed matterJournal Article1879-2766335912800008Q37895