Hydrated calcium oxalates

Crystal structures, thermal stability and phase evolution

Research outputpeer-review

4 Citations (Scopus)

Abstract

Thermal stability, structural evolution pathways, and phase transition mechanisms of the calcium oxalates whewellite (CaC 2O 4·H 2O), weddellite (CaC 2O 4·(2+x)H 2O), and caoxite (CaC 2O 4·3H 2O) have been analyzed using single crystal and powder X-ray diffraction (XRD). During single crystal XRD heating experiments, α-CaC 2O 4 and the novel calcium oxalate monohydrate have been obtained and structurally characterized for the first time. The highest thermal expansion of these compounds is observed along the direction of the hydrogen bonds, whereas the lowest expansion and even contraction of the structures occur due to the displacement of neighbor layered complexes toward each other and to an orthogonalization of the monoclinic angles. Within the calcium oxalate family, whewellite should be regarded as the most stable crystalline phase at ambient conditions. Weddellite and caoxite transform to whewellite during dehydration-driven phase transition promoted by time and/or heating.

Original languageEnglish
Pages (from-to)5465–5478
Number of pages14
JournalCrystal Growth and Design
Volume18
Issue number9
DOIs
Publication statusPublished - 5 Sep 2018

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Calcium Oxalate
oxalates
calcium
Calcium
Thermodynamic stability
thermal stability
Crystal structure
crystal structure
Phase transitions
Single crystals
Heating
heating
single crystals
Dehydration
diffraction
dehydration
X ray powder diffraction
contraction
Thermal expansion
thermal expansion

Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

Cite this

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title = "Hydrated calcium oxalates: Crystal structures, thermal stability and phase evolution",
abstract = "Thermal stability, structural evolution pathways, and phase transition mechanisms of the calcium oxalates whewellite (CaC 2O 4·H 2O), weddellite (CaC 2O 4·(2+x)H 2O), and caoxite (CaC 2O 4·3H 2O) have been analyzed using single crystal and powder X-ray diffraction (XRD). During single crystal XRD heating experiments, α-CaC 2O 4 and the novel calcium oxalate monohydrate have been obtained and structurally characterized for the first time. The highest thermal expansion of these compounds is observed along the direction of the hydrogen bonds, whereas the lowest expansion and even contraction of the structures occur due to the displacement of neighbor layered complexes toward each other and to an orthogonalization of the monoclinic angles. Within the calcium oxalate family, whewellite should be regarded as the most stable crystalline phase at ambient conditions. Weddellite and caoxite transform to whewellite during dehydration-driven phase transition promoted by time and/or heating.",
author = "Izatulina, {Alina R.} and Gurzhiy, {Vladislav V.} and Maria Krzhizhanovskaya and Kuz'Mina, {Mariya A.} and Matteo Leoni and Frank-Kamenetskaya, {Olga V.}",
year = "2018",
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pages = "5465–5478",
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publisher = "American Chemical Society",
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TY - JOUR

T1 - Hydrated calcium oxalates

T2 - Crystal structures, thermal stability and phase evolution

AU - Izatulina, Alina R.

AU - Gurzhiy, Vladislav V.

AU - Krzhizhanovskaya, Maria

AU - Kuz'Mina, Mariya A.

AU - Leoni, Matteo

AU - Frank-Kamenetskaya, Olga V.

PY - 2018/9/5

Y1 - 2018/9/5

N2 - Thermal stability, structural evolution pathways, and phase transition mechanisms of the calcium oxalates whewellite (CaC 2O 4·H 2O), weddellite (CaC 2O 4·(2+x)H 2O), and caoxite (CaC 2O 4·3H 2O) have been analyzed using single crystal and powder X-ray diffraction (XRD). During single crystal XRD heating experiments, α-CaC 2O 4 and the novel calcium oxalate monohydrate have been obtained and structurally characterized for the first time. The highest thermal expansion of these compounds is observed along the direction of the hydrogen bonds, whereas the lowest expansion and even contraction of the structures occur due to the displacement of neighbor layered complexes toward each other and to an orthogonalization of the monoclinic angles. Within the calcium oxalate family, whewellite should be regarded as the most stable crystalline phase at ambient conditions. Weddellite and caoxite transform to whewellite during dehydration-driven phase transition promoted by time and/or heating.

AB - Thermal stability, structural evolution pathways, and phase transition mechanisms of the calcium oxalates whewellite (CaC 2O 4·H 2O), weddellite (CaC 2O 4·(2+x)H 2O), and caoxite (CaC 2O 4·3H 2O) have been analyzed using single crystal and powder X-ray diffraction (XRD). During single crystal XRD heating experiments, α-CaC 2O 4 and the novel calcium oxalate monohydrate have been obtained and structurally characterized for the first time. The highest thermal expansion of these compounds is observed along the direction of the hydrogen bonds, whereas the lowest expansion and even contraction of the structures occur due to the displacement of neighbor layered complexes toward each other and to an orthogonalization of the monoclinic angles. Within the calcium oxalate family, whewellite should be regarded as the most stable crystalline phase at ambient conditions. Weddellite and caoxite transform to whewellite during dehydration-driven phase transition promoted by time and/or heating.

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U2 - 10.1021/acs.cgd.8b00826

DO - 10.1021/acs.cgd.8b00826

M3 - Article

VL - 18

SP - 5465

EP - 5478

JO - Crystal Growth and Design

JF - Crystal Growth and Design

SN - 1528-7483

IS - 9

ER -