Phase Transitions in Layered Diguanidinium Hexachlorostannate(IV)

Marek Szafranski, Kenny Ståhl

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Five crystalline phases of diguanidinium hexachlorostannate(IV), [C(NH2)(3)](2)SnCl6, have been identified and characterized by calorimetric and dielectric measurements, single crystal X-ray diffraction at atmospheric and high pressure, and synchrotron X-ray powder diffraction. The crystal structures of all phases are built of similar layers in which the tin hexachloride anions are connected to the guanidinium cations by N-H center dot center dot center dot Cl hydrogen bonds, forming a interact primarily by Coulombic forces between the ions from ap. double H-bonded sheets. The layers, neutral as a whole, the opposing H-bonded sheets, and through the van der Waals contacts. From water solution the compound crystallizes at room temperature in phase III of space group C2/c. On heating, this phase transforms between 375 and 455 K to the high temperature phase I of space group P (1) over bar, either immediately or through the intermediate phase II of the same space group P (1) over bar. The temperature range of phase II enhances meaningfully at elevated pressure, which made possible the high-pressure crystallization of this phase and determination of its structure. Different transition paths can be realized when the crystal is cooled from phase I: the reverse transition occurs in the monoclinic phase III or in the monoclinic phase IV (space group C2/m), or in the phase V of space group PT. In all phases the layered structure of the crystal is preserved, while the arrangement of the layers is different. The transitions involve also transformations in the networks of N-H center dot center dot center dot Cl hydrogen bonds. The large volume (similar to 3%) and entropy (similar to R ln 3) change at the transition between phases II and III, and the giant pressure coefficient of -755 K GPa(-1), indicate a great potential of this material for applications in solid-state cooling systems.
Original languageEnglish
JournalCrystal Growth & Design
Volume16
Issue number4
Pages (from-to)2157-2166
Number of pages10
ISSN1528-7483
DOIs
Publication statusPublished - 2016

Cite this

@article{103ce38c6e1b44259c06c2cd04a9a726,
title = "Phase Transitions in Layered Diguanidinium Hexachlorostannate(IV)",
abstract = "Five crystalline phases of diguanidinium hexachlorostannate(IV), [C(NH2)(3)](2)SnCl6, have been identified and characterized by calorimetric and dielectric measurements, single crystal X-ray diffraction at atmospheric and high pressure, and synchrotron X-ray powder diffraction. The crystal structures of all phases are built of similar layers in which the tin hexachloride anions are connected to the guanidinium cations by N-H center dot center dot center dot Cl hydrogen bonds, forming a interact primarily by Coulombic forces between the ions from ap. double H-bonded sheets. The layers, neutral as a whole, the opposing H-bonded sheets, and through the van der Waals contacts. From water solution the compound crystallizes at room temperature in phase III of space group C2/c. On heating, this phase transforms between 375 and 455 K to the high temperature phase I of space group P (1) over bar, either immediately or through the intermediate phase II of the same space group P (1) over bar. The temperature range of phase II enhances meaningfully at elevated pressure, which made possible the high-pressure crystallization of this phase and determination of its structure. Different transition paths can be realized when the crystal is cooled from phase I: the reverse transition occurs in the monoclinic phase III or in the monoclinic phase IV (space group C2/m), or in the phase V of space group PT. In all phases the layered structure of the crystal is preserved, while the arrangement of the layers is different. The transitions involve also transformations in the networks of N-H center dot center dot center dot Cl hydrogen bonds. The large volume (similar to 3{\%}) and entropy (similar to R ln 3) change at the transition between phases II and III, and the giant pressure coefficient of -755 K GPa(-1), indicate a great potential of this material for applications in solid-state cooling systems.",
author = "Marek Szafranski and Kenny St{\aa}hl",
year = "2016",
doi = "10.1021/acs.cgd.5b01830",
language = "English",
volume = "16",
pages = "2157--2166",
journal = "Crystal Growth & Design",
issn = "1528-7483",
publisher = "American Chemical Society",
number = "4",

}

Phase Transitions in Layered Diguanidinium Hexachlorostannate(IV). / Szafranski, Marek; Ståhl, Kenny.

In: Crystal Growth & Design, Vol. 16, No. 4, 2016, p. 2157-2166.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Phase Transitions in Layered Diguanidinium Hexachlorostannate(IV)

AU - Szafranski, Marek

AU - Ståhl, Kenny

PY - 2016

Y1 - 2016

N2 - Five crystalline phases of diguanidinium hexachlorostannate(IV), [C(NH2)(3)](2)SnCl6, have been identified and characterized by calorimetric and dielectric measurements, single crystal X-ray diffraction at atmospheric and high pressure, and synchrotron X-ray powder diffraction. The crystal structures of all phases are built of similar layers in which the tin hexachloride anions are connected to the guanidinium cations by N-H center dot center dot center dot Cl hydrogen bonds, forming a interact primarily by Coulombic forces between the ions from ap. double H-bonded sheets. The layers, neutral as a whole, the opposing H-bonded sheets, and through the van der Waals contacts. From water solution the compound crystallizes at room temperature in phase III of space group C2/c. On heating, this phase transforms between 375 and 455 K to the high temperature phase I of space group P (1) over bar, either immediately or through the intermediate phase II of the same space group P (1) over bar. The temperature range of phase II enhances meaningfully at elevated pressure, which made possible the high-pressure crystallization of this phase and determination of its structure. Different transition paths can be realized when the crystal is cooled from phase I: the reverse transition occurs in the monoclinic phase III or in the monoclinic phase IV (space group C2/m), or in the phase V of space group PT. In all phases the layered structure of the crystal is preserved, while the arrangement of the layers is different. The transitions involve also transformations in the networks of N-H center dot center dot center dot Cl hydrogen bonds. The large volume (similar to 3%) and entropy (similar to R ln 3) change at the transition between phases II and III, and the giant pressure coefficient of -755 K GPa(-1), indicate a great potential of this material for applications in solid-state cooling systems.

AB - Five crystalline phases of diguanidinium hexachlorostannate(IV), [C(NH2)(3)](2)SnCl6, have been identified and characterized by calorimetric and dielectric measurements, single crystal X-ray diffraction at atmospheric and high pressure, and synchrotron X-ray powder diffraction. The crystal structures of all phases are built of similar layers in which the tin hexachloride anions are connected to the guanidinium cations by N-H center dot center dot center dot Cl hydrogen bonds, forming a interact primarily by Coulombic forces between the ions from ap. double H-bonded sheets. The layers, neutral as a whole, the opposing H-bonded sheets, and through the van der Waals contacts. From water solution the compound crystallizes at room temperature in phase III of space group C2/c. On heating, this phase transforms between 375 and 455 K to the high temperature phase I of space group P (1) over bar, either immediately or through the intermediate phase II of the same space group P (1) over bar. The temperature range of phase II enhances meaningfully at elevated pressure, which made possible the high-pressure crystallization of this phase and determination of its structure. Different transition paths can be realized when the crystal is cooled from phase I: the reverse transition occurs in the monoclinic phase III or in the monoclinic phase IV (space group C2/m), or in the phase V of space group PT. In all phases the layered structure of the crystal is preserved, while the arrangement of the layers is different. The transitions involve also transformations in the networks of N-H center dot center dot center dot Cl hydrogen bonds. The large volume (similar to 3%) and entropy (similar to R ln 3) change at the transition between phases II and III, and the giant pressure coefficient of -755 K GPa(-1), indicate a great potential of this material for applications in solid-state cooling systems.

U2 - 10.1021/acs.cgd.5b01830

DO - 10.1021/acs.cgd.5b01830

M3 - Journal article

VL - 16

SP - 2157

EP - 2166

JO - Crystal Growth & Design

JF - Crystal Growth & Design

SN - 1528-7483

IS - 4

ER -