The influence of the relative thermal expansion and electric permittivity on phase transitions in the perovskite-type bidimensional layered NH 3 (CH 2 ) 3 NH 3 CdBr 4 compound

Thermal, ferroelastic, and structural properties near phase transitions of organic–inorganic perovskite type [NH3(CH2)3NH3]CdBr4 crystals

“…, its stable phase at the highest temperature is the one with the lowest symmetry. 30 This crystal undergoes two phase transitions, at temperatures of 326 K (= T C2 ) and 368 K (= T C1 ). 10,30 The room temperature phase III was determined in the space group Pnma (point group mmm ) of the orthorhombic structure.…”

“…Its lattice constants have been reported as a = 7.721 Å, b = 19.054 Å, c = 7.898 Å, and Z = 4. 30 In this phase, Cd atoms are surrounded by six bromine atoms forming a nearly regular octahedron CdBr 6 . Of these six bromine atoms, four Br atoms are bridging atoms shared with the neighboring octahedral, and two Br atoms are terminal atoms resulting in bidimensional anion planes.…”

“…The monoclinic angle β abruptly increases with increasing temperature, reaching approximately 95.5° in this phase, whereas in phases II and III, its value was constant at β = 90°. 30 …”

Phase Transition and Dielectric Response Originating from Disorder‐Order Transition in the In‐Based Organic‐Inorganic Hybrid Material [NH3(CH2)5NH3][InCl5(H2O)] ⋅ H2O

“…Recently, a series of new alkylenediammonium halogenometallate (III) phase transition compounds were reported. [19][20][21][22][23] For example, Liao's group obtained two organicinorganic hybrid materials, [NH 3 (CH 2 ) 5 NH 3 ][SbBr 5 ] and [NH 3 (CH 2 ) 5 NH 3 ][SbCl 5 ], which exhibit a dielectric anomaly at around 366.5 K and 365.4 K, respectively. The space group of these two compounds changes from Pnma at 393 K to P2 1 2 1 2 1 at 293 K. The phase transition is ascribed to the disorder-order transformation of the 1,5-pentanediammonium cations.…”

“…Therefore, the most critical factor in the design of organic‐inorganic hybrid materials is to find dynamic organic ammonium cations that tend to experience a disorder‐order transformation. Recently, a series of new alkylenediammonium halogenometallate (III) phase transition compounds were reported [19–23] . For example, Liao's group obtained two organic‐inorganic hybrid materials, [NH 3 (CH 2 ) 5 NH 3 ][SbBr 5 ] and [NH 3 (CH 2 ) 5 NH 3 ][SbCl 5 ], which exhibit a dielectric anomaly at around 366.5 K and 365.4 K, respectively.…”