We report the strong correlation between anomalous thermal expansion in solid-solid volumetric phase transition and the barocaloric effect. This investigation was carried out in {Fe[H₂B(pz)₂]₂(bipy)} (pz = pyrazolyl; bipy = bipyridine) spin crossover system, in which the spin of Fe²⁺ changes from s_LS = 0 to s_HS = 2 coupled with high unit cell volume changes from V_LS = 2356 to V_HS = 2462 Å³, at T_1/2–160 K. Giant barocaloric effect, through the isothermal entropy change (ΔS_T = 60 J kg⁻¹ K⁻¹) upon moderated hydrostatic pressure variation (ΔP = 1 kbar), was indirectly obtained from reported pressure dependence of magnetic susceptibility. Theoretical results, obtained from our microscopic model, updated with the reported metal-ligand asymmetrical stretching z-vibration modes, from DFT calculation, showed a remarkable agreement with the experimental data.

我们报告了固体-固体体积相变中的异常热膨胀与压力热效应之间的强相关性。本研究在 {Fe[H ₂ B(pz) ₂ ] ₂ (bipy)} (pz = pyrazolyl; bipy = bipyridine) 自旋交叉系统中进行，其中 Fe ²⁺的自旋从 s _LS  = 0 变为小号_HS  = 2加上高的晶胞体积的变化从V _LS  = 2356到V _HS  = 2462埃³，在T _1/2 -160 K.巨barocaloric效果，通过等温熵变（ΔS _Ť  =为60J公斤^{- 1}  K ^-1) 在缓和静水压力变化 (ΔP = 1 kbar) 时，是从报告的磁化率的压力依赖性间接获得的。从我们的微观模型获得的理论结果，更新了报告的金属配体不对称拉伸 z 振动模式，从 DFT 计算，显示出与实验数据的显着一致性。