Phase transitions in [Ca(H2O)4](ClO4)2 studied by differential scanning calorimetry, X-ray single crystal diffraction and neutron powder diffraction

被引：5

作者：

Hetmanczyk, Joanna ^{[1
]}

Hetmanczyk, Lukasz ^{[1
]}

Migdal-Mikuli, Anna ^{[1
]}

Mikuli, Edward ^{[1
]}

Nitek, Wojciech ^{[2
]}

机构：

[1] Jagiellonian Univ, Fac Chem, Dept Chem Phys, PL-30060 Krakow, Poland

[2] Jagiellonian Univ, Fac Chem, Dept Crystal Chem & Crystal Phys, PL-30060 Krakow, Poland

来源：

JOURNAL OF MOLECULAR STRUCTURE | 2008年 / 891卷 / 1-3期

关键词：

Tetraaquacalcium perchlorate; Phase transitions; Structural changes; Differential scanning calorimetry; X-ray single crystal diffraction; Neutron powder diffraction;

D O I：

10.1016/j.molstruc.2008.03.036

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Four phase transitions at: T-C1(h) = 267.1 K, T-C2(h) = 258.8 K, T-C3(h) = 254.1 K and T-C4(h) = 195.4 K (on heating) and at T-C1(c) = 263.8 K, T-C2(c) = 255.4 K, T-C3(c) = 246.0 K (on cooling) were determined for [Ca(H2O)(4)](ClO4)(2) between 90 and 295 K by means of differential scanning calorimetry (DSC). Phase transitions discovered at T-C1, T-C2 and T-C3 are connected with small change of the crystal structure. Namely, there are scant but statistically significant differences between unit cell parameters (angles: alpha, beta, gamma) and torsion angles in the structure of [Ca(H2O)(4)](ClO4)(2) at 293 and 240 K. The space group (P (1) over bar; No. 2) is the same for high, intermediate and low temperature phase, however, changes of perchlorate anions orientations are distinctly visible. (C) 2008 Elsevier B.V. All rights reserved.

引用

页码：233 / 241

页数：9

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