Energetics of formation of alkali and ammonium cobalt and zinc phosphate frameworks

So Nhu Le; Alexandra Navrotsky

doi:10.1016/j.jssc.2007.10.017

Energetics of formation of alkali and ammonium cobalt and zinc phosphate frameworks

So Nhu Le, Alexandra Navrotsky

Research output: Contribution to journal › Article › peer-review

16 Scopus citations

Abstract

Alkali and ammonium cobalt and zinc phosphates show extensive polymorphism. Thermal behavior, relative stabilities, and enthalpies of formation of KCoPO₄, RbCoPO₄, NH₄CoPO₄, and NH₄ZnPO₄ polymorphs are studied by differential scanning calorimetry, high-temperature oxide melt solution calorimetry, and acid solution calorimetry. α-KCoPO₄ and γ-KCoPO₄ are very similar in enthalpy. γ-KCoPO₄ slowly transforms to α-KCoPO₄ near 673 K. The high-temperature phase, β-KCoPO₄, is 5-7 kJ mol^-1 higher in enthalpy than α-KCoPO₄ and γ-KCoPO₄. HEX phases of NH₄CoPO₄ and NH₄ZnPO₄ are about 3 kJ mol^-1 lower in enthalpy than the corresponding ABW phases. There is a strong relationship between enthalpy of formation from oxides and acid-base interaction for cobalt and zinc phosphates and also for aluminosilicates with related frameworks. Cobalt and zinc phosphates exhibit similar trends in enthalpies of formation from oxides as aluminosilicates, but their enthalpies of formation from oxides are more exothermic because of their stronger acid-base interactions. Enthalpies of formation from ammonia and oxides of NH₄CoPO₄ and NH₄ZnPO₄ are similar, reflecting the similar basicity of CoO and ZnO.

Original language	English (US)
Pages (from-to)	20-29
Number of pages	10
Journal	Journal of Solid State Chemistry
Volume	181
Issue number	1
DOIs	https://doi.org/10.1016/j.jssc.2007.10.017
State	Published - Jan 2008
Externally published	Yes

Keywords

Cobalt phosphate framework
Enthalpy of formation
KCoPO
NHCoPO
NHZnPO
Phase transformation
RbCoPO
Zinc phosphate framework

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Condensed Matter Physics
Physical and Theoretical Chemistry
Inorganic Chemistry
Materials Chemistry

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10.1016/j.jssc.2007.10.017

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@article{4399ec6cbdad4bbfac764d7ac0ab5add,

title = "Energetics of formation of alkali and ammonium cobalt and zinc phosphate frameworks",

abstract = "Alkali and ammonium cobalt and zinc phosphates show extensive polymorphism. Thermal behavior, relative stabilities, and enthalpies of formation of KCoPO4, RbCoPO4, NH4CoPO4, and NH4ZnPO4 polymorphs are studied by differential scanning calorimetry, high-temperature oxide melt solution calorimetry, and acid solution calorimetry. α-KCoPO4 and γ-KCoPO4 are very similar in enthalpy. γ-KCoPO4 slowly transforms to α-KCoPO4 near 673 K. The high-temperature phase, β-KCoPO4, is 5-7 kJ mol-1 higher in enthalpy than α-KCoPO4 and γ-KCoPO4. HEX phases of NH4CoPO4 and NH4ZnPO4 are about 3 kJ mol-1 lower in enthalpy than the corresponding ABW phases. There is a strong relationship between enthalpy of formation from oxides and acid-base interaction for cobalt and zinc phosphates and also for aluminosilicates with related frameworks. Cobalt and zinc phosphates exhibit similar trends in enthalpies of formation from oxides as aluminosilicates, but their enthalpies of formation from oxides are more exothermic because of their stronger acid-base interactions. Enthalpies of formation from ammonia and oxides of NH4CoPO4 and NH4ZnPO4 are similar, reflecting the similar basicity of CoO and ZnO.",

keywords = "Cobalt phosphate framework, Enthalpy of formation, KCoPO, NHCoPO, NHZnPO, Phase transformation, RbCoPO, Zinc phosphate framework",

author = "Le, {So Nhu} and Alexandra Navrotsky",

note = "Funding Information: This work was supported by the National Science Foundation under Grant DMR 06-01892. We thank Sarah Roeske and Sean Mulcahy for microprobe analysis and John Neil and Lan Wang for providing the CoO sample. ",

year = "2008",

month = jan,

doi = "10.1016/j.jssc.2007.10.017",

language = "English (US)",

volume = "181",

pages = "20--29",

journal = "Journal of Solid State Chemistry",

issn = "0022-4596",

publisher = "Academic Press Inc.",

number = "1",

}

TY - JOUR

T1 - Energetics of formation of alkali and ammonium cobalt and zinc phosphate frameworks

AU - Le, So Nhu

AU - Navrotsky, Alexandra

N1 - Funding Information: This work was supported by the National Science Foundation under Grant DMR 06-01892. We thank Sarah Roeske and Sean Mulcahy for microprobe analysis and John Neil and Lan Wang for providing the CoO sample.

PY - 2008/1

Y1 - 2008/1

N2 - Alkali and ammonium cobalt and zinc phosphates show extensive polymorphism. Thermal behavior, relative stabilities, and enthalpies of formation of KCoPO4, RbCoPO4, NH4CoPO4, and NH4ZnPO4 polymorphs are studied by differential scanning calorimetry, high-temperature oxide melt solution calorimetry, and acid solution calorimetry. α-KCoPO4 and γ-KCoPO4 are very similar in enthalpy. γ-KCoPO4 slowly transforms to α-KCoPO4 near 673 K. The high-temperature phase, β-KCoPO4, is 5-7 kJ mol-1 higher in enthalpy than α-KCoPO4 and γ-KCoPO4. HEX phases of NH4CoPO4 and NH4ZnPO4 are about 3 kJ mol-1 lower in enthalpy than the corresponding ABW phases. There is a strong relationship between enthalpy of formation from oxides and acid-base interaction for cobalt and zinc phosphates and also for aluminosilicates with related frameworks. Cobalt and zinc phosphates exhibit similar trends in enthalpies of formation from oxides as aluminosilicates, but their enthalpies of formation from oxides are more exothermic because of their stronger acid-base interactions. Enthalpies of formation from ammonia and oxides of NH4CoPO4 and NH4ZnPO4 are similar, reflecting the similar basicity of CoO and ZnO.

AB - Alkali and ammonium cobalt and zinc phosphates show extensive polymorphism. Thermal behavior, relative stabilities, and enthalpies of formation of KCoPO4, RbCoPO4, NH4CoPO4, and NH4ZnPO4 polymorphs are studied by differential scanning calorimetry, high-temperature oxide melt solution calorimetry, and acid solution calorimetry. α-KCoPO4 and γ-KCoPO4 are very similar in enthalpy. γ-KCoPO4 slowly transforms to α-KCoPO4 near 673 K. The high-temperature phase, β-KCoPO4, is 5-7 kJ mol-1 higher in enthalpy than α-KCoPO4 and γ-KCoPO4. HEX phases of NH4CoPO4 and NH4ZnPO4 are about 3 kJ mol-1 lower in enthalpy than the corresponding ABW phases. There is a strong relationship between enthalpy of formation from oxides and acid-base interaction for cobalt and zinc phosphates and also for aluminosilicates with related frameworks. Cobalt and zinc phosphates exhibit similar trends in enthalpies of formation from oxides as aluminosilicates, but their enthalpies of formation from oxides are more exothermic because of their stronger acid-base interactions. Enthalpies of formation from ammonia and oxides of NH4CoPO4 and NH4ZnPO4 are similar, reflecting the similar basicity of CoO and ZnO.

KW - Cobalt phosphate framework

KW - Enthalpy of formation

KW - KCoPO

KW - NHCoPO

KW - NHZnPO

KW - Phase transformation

KW - RbCoPO

KW - Zinc phosphate framework

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U2 - 10.1016/j.jssc.2007.10.017

DO - 10.1016/j.jssc.2007.10.017

M3 - Article

AN - SCOPUS:37549046074

SN - 0022-4596

VL - 181

SP - 20

EP - 29

JO - Journal of Solid State Chemistry

JF - Journal of Solid State Chemistry

IS - 1

ER -

Energetics of formation of alkali and ammonium cobalt and zinc phosphate frameworks

Abstract

Keywords

ASJC Scopus subject areas

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