Water-presence dependent switchable ferroelectricity was discovered in the hybrid organic–inorganic zinc oxalate 1D coordination polymer (DABCOH₂)[Zn(C₂O₄)₂]·3H₂O (DZnOH, where DABCOH₂: diprotonated 1.4-diazoniabicyclo[2.2.2]octane). The compound undergoes a reversible para–ferroelectric phase transition at 207 K from room temperature centrosymmetric phase I (space group P2₁/n) to low-temperature non-centrosymmetric phase II (space group P2₁). The microscopic mechanism of the phase transition is directly associated with the reconstruction of the hydrogen-bond network. On heating, the crystals exhibit a reversible single-crystal to single-crystal transformation concerned with the removal of all water molecules giving anhydrous DABCO zinc oxalate (DABCOH₂)[Zn(C₂O₄)₂] (DZnO). The dehydrated compound does not show ferroelectric properties.

中文翻译：

---

有机模板草酸锌配位聚合物的顺电-铁电相变†

在有机-无机草酸锌一维配位聚合物（DABCOH ₂）[Zn（C ₂ O ₄）₂ ]·3H ₂ O（DZnOH，其中DABCOH ₂：双质子化的1.4-二氮杂双环[2.2 ）中发现了水依赖性的可转换铁电。.2]辛烷）。该化合物经历可逆对在207ķ从室温中心对称相-ferroelectric相转变I（空间群P 2 ₁ / Ñ）低温非中心对称相II（空间群P 2 ₁）。相变的微观机制与氢键网络的重建直接相关。加热时，晶体表现出可逆的单晶至单晶转变，这涉及去除所有水分子，从而得到无水DABCO草酸锌（DABCOH ₂）[Zn（C ₂ O ₄）₂ ]（DZnO）。脱水的化合物不显示铁电性质。