Thermodynamics of vivianite-group arsenates M3(AsO4)2.8H2O (M is Ni, Co, Mg, Zn, Cu) and chemical variability in the natural arsenates of this group

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00023272%3A_____%2F24%3A10136227" target="_blank" >RIV/00023272:_____/24:10136227 - isvavai.cz</a>

Result on the web

<a href="https://ejm.copernicus.org/articles/36/31/2024/" target="_blank" >https://ejm.copernicus.org/articles/36/31/2024/</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.5194/ejm-36-31-2024" target="_blank" >10.5194/ejm-36-31-2024</a>

Result language

angličtina

Original language name

Thermodynamics of vivianite-group arsenates M3(AsO4)2.8H2O (M is Ni, Co, Mg, Zn, Cu) and chemical variability in the natural arsenates of this group

Original language description

In this work, we investigated the M3(AsO4)2.8H2O end members annabergite (M = Ni), erythrite (M = Co), hornesite (M = Mg), and their solid solutions. Acid-solution calorimetry and relaxation calorimetry were used to determine the solubility products (logKsp) for annabergite (MINUS SIGN 33.7), erythrite (MINUS SIGN 32.1), and hornesite (MINUS SIGN 22.3). Solubility products for other end members of this group were extracted from literature and critically evaluated. The enthalpies of mixing are complex, related to subsystems M(1)3(AsO4)2.8H2O - M(1)M(2)2(AsO4)2.8H2O and M(1)M(2)2(AsO4)2.8H2O - M(2)3(AsO4)2.8H2O. They are small and positive for the annabergite-erythrite solid solution and small and negative for the annabergite-hornesite solid solution. Autocorrelation analysis of FTIR spectra shows correlation of strain decrease in the structure with the negative enthalpies of mixing in the annabergite-hornesite solid solution. A set of more than 600 electron microprobe analyses of the M3(AsO4)2.8H2O minerals documents the variability and complexity in this group. Most common compositions are those dominated by Ni, Co, or Ni-Co. The analytical results were used to calculate the maximal configurational entropies which could be a factor that compensates for the small enthalpies of mixing in the annabergite-erythrite solid solution. The data presented here can be used to model sites polluted with metals and arsenic and to enhance our understanding of complex solid solutions.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10504 - Mineralogy

Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

European Journal of Mineralogy

ISSN

1617-4011

e-ISSN

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Volume of the periodical

36

Issue of the periodical within the volume

1

Country of publishing house

DE - GERMANY

Number of pages

24

Pages from-to

31-54

UT code for WoS article

001173378300001

EID of the result in the Scopus database

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