Quaternary selenostannates Na2-xGa2-xSn 1+xSe6 and AGaSnSe4 (A=K, Rb, and Cs) through rapid cooling of melts. Kinetics versus thermodynamics in the polymorphism of AGaSnSe4

Seong Ju Hwang, Ratnasabapathy G. Iyer, Mercouri G Kanatzidis

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Abstract

The quaternary alkali-metal gallium selenostannates, Na 2-xGa2-xSn1+xSe6 and AGaSnSe 4 (A=K, Rb, and Cs), were synthesized by reacting alkali-metal selenide, Ga, Sn, and Se with a flame melting-rapid cooling method. Na 2-xGa2-xSn1+xSe6 crystallizes in the non-centrosymmetric space group C2 with cell constants a=13.308(3)Å, b=7.594(2)Å, c=13.842(3)Å, β=118.730(4)°, V=1226.7(5)Å3. α-KGaSnSe4 crystallizes in the tetragonal space group I4/mcm with a=8.186(5)Å and c=6.403(5)Å, V=429.1(5)Å3. β-KGaSnSe4 crystallizes in the space group P21/c with cell constants a=7.490(2)Å, b=12.578(3)Å, c=18.306(5)Å, β=98.653(5)°, V=1705.0(8)Å3. The unit cell of isostructural RbGaSnSe 4 is a=7.567(2)Å, b=12.656(3)Å, c=18.277(4)Å, β=95.924(4)°, V=1741.1(7)Å3. CsGaSnSe4 crystallizes in the orthorhombic space group Pmcn with a=7.679(2)Å, b=12.655(3)Å, c=18.278(5)Å, V=1776.1(8)Å3. The structure of Na2-xGa2-xSn1+xSe6 consists of a polar three-dimensional network of trimeric (Sn,Ga) 3Se9 units with Na atoms located in tunnels. The AGaSnSe4 possess layered structures. The compounds show nearly the same Raman spectral features, except for Na2-xGa2-xSn 1+xSe6. Optical band gaps, determined from UV-Vis spectroscopy, range from 1.50eV in Na2-xGa2-xSn 1+xSe6 to 1.97eV in CsGaSnSe4. Cooling of the melts of KGaSnSe4 and RbGaSnSe4 produces only kinetically stable products. The thermodynamically stable product is accessible under extended annealing, which leads to the so-called γ-form (BaGa 2S4-type) of these compounds.

Original languageEnglish
Pages (from-to)3640-3649
Number of pages10
JournalJournal of Solid State Chemistry
Volume177
Issue number10
DOIs
Publication statusPublished - Oct 2004

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Alkali Metals
polymorphism
Alkali metals
Polymorphism
Thermodynamics
Cooling
cooling
thermodynamics
Gallium
Kinetics
Optical band gaps
kinetics
Ultraviolet spectroscopy
alkali metals
Tunnels
Melting
cells
Annealing
Atoms
selenides

Keywords

  • Chalcogenicles
  • Frame melting
  • Low-dimensional
  • Phase-transitions
  • Polymorphism
  • Selenostannates

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Physical and Theoretical Chemistry
  • Materials Chemistry

Cite this

@article{7a278653596d407eb0a4b475715b424f,
title = "Quaternary selenostannates Na2-xGa2-xSn 1+xSe6 and AGaSnSe4 (A=K, Rb, and Cs) through rapid cooling of melts. Kinetics versus thermodynamics in the polymorphism of AGaSnSe4",
abstract = "The quaternary alkali-metal gallium selenostannates, Na 2-xGa2-xSn1+xSe6 and AGaSnSe 4 (A=K, Rb, and Cs), were synthesized by reacting alkali-metal selenide, Ga, Sn, and Se with a flame melting-rapid cooling method. Na 2-xGa2-xSn1+xSe6 crystallizes in the non-centrosymmetric space group C2 with cell constants a=13.308(3){\AA}, b=7.594(2){\AA}, c=13.842(3){\AA}, β=118.730(4)°, V=1226.7(5){\AA}3. α-KGaSnSe4 crystallizes in the tetragonal space group I4/mcm with a=8.186(5){\AA} and c=6.403(5){\AA}, V=429.1(5){\AA}3. β-KGaSnSe4 crystallizes in the space group P21/c with cell constants a=7.490(2){\AA}, b=12.578(3){\AA}, c=18.306(5){\AA}, β=98.653(5)°, V=1705.0(8){\AA}3. The unit cell of isostructural RbGaSnSe 4 is a=7.567(2){\AA}, b=12.656(3){\AA}, c=18.277(4){\AA}, β=95.924(4)°, V=1741.1(7){\AA}3. CsGaSnSe4 crystallizes in the orthorhombic space group Pmcn with a=7.679(2){\AA}, b=12.655(3){\AA}, c=18.278(5){\AA}, V=1776.1(8){\AA}3. The structure of Na2-xGa2-xSn1+xSe6 consists of a polar three-dimensional network of trimeric (Sn,Ga) 3Se9 units with Na atoms located in tunnels. The AGaSnSe4 possess layered structures. The compounds show nearly the same Raman spectral features, except for Na2-xGa2-xSn 1+xSe6. Optical band gaps, determined from UV-Vis spectroscopy, range from 1.50eV in Na2-xGa2-xSn 1+xSe6 to 1.97eV in CsGaSnSe4. Cooling of the melts of KGaSnSe4 and RbGaSnSe4 produces only kinetically stable products. The thermodynamically stable product is accessible under extended annealing, which leads to the so-called γ-form (BaGa 2S4-type) of these compounds.",
keywords = "Chalcogenicles, Frame melting, Low-dimensional, Phase-transitions, Polymorphism, Selenostannates",
author = "Hwang, {Seong Ju} and Iyer, {Ratnasabapathy G.} and Kanatzidis, {Mercouri G}",
year = "2004",
month = "10",
doi = "10.1016/j.jssc.2004.06.019",
language = "English",
volume = "177",
pages = "3640--3649",
journal = "Journal of Solid State Chemistry",
issn = "0022-4596",
publisher = "Academic Press Inc.",
number = "10",

}

TY - JOUR

T1 - Quaternary selenostannates Na2-xGa2-xSn 1+xSe6 and AGaSnSe4 (A=K, Rb, and Cs) through rapid cooling of melts. Kinetics versus thermodynamics in the polymorphism of AGaSnSe4

AU - Hwang, Seong Ju

AU - Iyer, Ratnasabapathy G.

AU - Kanatzidis, Mercouri G

PY - 2004/10

Y1 - 2004/10

N2 - The quaternary alkali-metal gallium selenostannates, Na 2-xGa2-xSn1+xSe6 and AGaSnSe 4 (A=K, Rb, and Cs), were synthesized by reacting alkali-metal selenide, Ga, Sn, and Se with a flame melting-rapid cooling method. Na 2-xGa2-xSn1+xSe6 crystallizes in the non-centrosymmetric space group C2 with cell constants a=13.308(3)Å, b=7.594(2)Å, c=13.842(3)Å, β=118.730(4)°, V=1226.7(5)Å3. α-KGaSnSe4 crystallizes in the tetragonal space group I4/mcm with a=8.186(5)Å and c=6.403(5)Å, V=429.1(5)Å3. β-KGaSnSe4 crystallizes in the space group P21/c with cell constants a=7.490(2)Å, b=12.578(3)Å, c=18.306(5)Å, β=98.653(5)°, V=1705.0(8)Å3. The unit cell of isostructural RbGaSnSe 4 is a=7.567(2)Å, b=12.656(3)Å, c=18.277(4)Å, β=95.924(4)°, V=1741.1(7)Å3. CsGaSnSe4 crystallizes in the orthorhombic space group Pmcn with a=7.679(2)Å, b=12.655(3)Å, c=18.278(5)Å, V=1776.1(8)Å3. The structure of Na2-xGa2-xSn1+xSe6 consists of a polar three-dimensional network of trimeric (Sn,Ga) 3Se9 units with Na atoms located in tunnels. The AGaSnSe4 possess layered structures. The compounds show nearly the same Raman spectral features, except for Na2-xGa2-xSn 1+xSe6. Optical band gaps, determined from UV-Vis spectroscopy, range from 1.50eV in Na2-xGa2-xSn 1+xSe6 to 1.97eV in CsGaSnSe4. Cooling of the melts of KGaSnSe4 and RbGaSnSe4 produces only kinetically stable products. The thermodynamically stable product is accessible under extended annealing, which leads to the so-called γ-form (BaGa 2S4-type) of these compounds.

AB - The quaternary alkali-metal gallium selenostannates, Na 2-xGa2-xSn1+xSe6 and AGaSnSe 4 (A=K, Rb, and Cs), were synthesized by reacting alkali-metal selenide, Ga, Sn, and Se with a flame melting-rapid cooling method. Na 2-xGa2-xSn1+xSe6 crystallizes in the non-centrosymmetric space group C2 with cell constants a=13.308(3)Å, b=7.594(2)Å, c=13.842(3)Å, β=118.730(4)°, V=1226.7(5)Å3. α-KGaSnSe4 crystallizes in the tetragonal space group I4/mcm with a=8.186(5)Å and c=6.403(5)Å, V=429.1(5)Å3. β-KGaSnSe4 crystallizes in the space group P21/c with cell constants a=7.490(2)Å, b=12.578(3)Å, c=18.306(5)Å, β=98.653(5)°, V=1705.0(8)Å3. The unit cell of isostructural RbGaSnSe 4 is a=7.567(2)Å, b=12.656(3)Å, c=18.277(4)Å, β=95.924(4)°, V=1741.1(7)Å3. CsGaSnSe4 crystallizes in the orthorhombic space group Pmcn with a=7.679(2)Å, b=12.655(3)Å, c=18.278(5)Å, V=1776.1(8)Å3. The structure of Na2-xGa2-xSn1+xSe6 consists of a polar three-dimensional network of trimeric (Sn,Ga) 3Se9 units with Na atoms located in tunnels. The AGaSnSe4 possess layered structures. The compounds show nearly the same Raman spectral features, except for Na2-xGa2-xSn 1+xSe6. Optical band gaps, determined from UV-Vis spectroscopy, range from 1.50eV in Na2-xGa2-xSn 1+xSe6 to 1.97eV in CsGaSnSe4. Cooling of the melts of KGaSnSe4 and RbGaSnSe4 produces only kinetically stable products. The thermodynamically stable product is accessible under extended annealing, which leads to the so-called γ-form (BaGa 2S4-type) of these compounds.

KW - Chalcogenicles

KW - Frame melting

KW - Low-dimensional

KW - Phase-transitions

KW - Polymorphism

KW - Selenostannates

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U2 - 10.1016/j.jssc.2004.06.019

DO - 10.1016/j.jssc.2004.06.019

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EP - 3649

JO - Journal of Solid State Chemistry

JF - Journal of Solid State Chemistry

SN - 0022-4596

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