Thermodynamics of schafarzikite (FeSb2O4) and tripuhyite (FeSbO4)

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F23%3A10168787" target="_blank" >RIV/00025798:_____/23:10168787 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1007/s00269-023-01249-2" target="_blank" >https://doi.org/10.1007/s00269-023-01249-2</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s00269-023-01249-2" target="_blank" >10.1007/s00269-023-01249-2</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Thermodynamics of schafarzikite (FeSb2O4) and tripuhyite (FeSbO4)

Popis výsledku v původním jazyce

In this work, we investigated the thermodynamic properties of synthetic schafarzikite (FeSb2O4) and tripuhyite (FeSbO4). Low-temperature heat capacity ( C p) was determined by relaxation calorimetry. From these data, third-law entropy was calculated as 110.7 +/- 1.3 J mol(-1)K(-1) for tripuhyite and 187.1 +/- 2.2 J mol(-1) K-1 for schafarzikite. Using previously published Delta(f)G degrees values for both phases, we calculated their Delta H-f degrees as -947.8 +/- 2.2 for tripuhyite and -1061.2 +/- 4.4 for schafarzikite. The accuracy of the data sets was tested by entropy estimates and calculation of Delta H-f degrees from estimated lattice energies (via Kapustinskii equation). Measurements of C-p above T = 300 K were augmented by extrapolation to T = 700 K with the frequencies of acoustic and optic modes, using the Kieffer C-p model. A set of equilibrium constants (log K) for tripuhyite, schafarzikite, and several related phases was calculated and presented in a format that can be employed in commonly used geochemical codes. Calculations suggest that tripuhyite has a stability field that extends over a wide range of pH-p epsilon conditions at T = 298.15 K. Schafarzikite and hydrothermal oxides of antimony (valentinite, kermesite, and senarmontite) can form by oxidative dissolution and remobilization of pre-existing stibnite ores.

Název v anglickém jazyce

Thermodynamics of schafarzikite (FeSb2O4) and tripuhyite (FeSbO4)

Popis výsledku anglicky

In this work, we investigated the thermodynamic properties of synthetic schafarzikite (FeSb2O4) and tripuhyite (FeSbO4). Low-temperature heat capacity ( C p) was determined by relaxation calorimetry. From these data, third-law entropy was calculated as 110.7 +/- 1.3 J mol(-1)K(-1) for tripuhyite and 187.1 +/- 2.2 J mol(-1) K-1 for schafarzikite. Using previously published Delta(f)G degrees values for both phases, we calculated their Delta H-f degrees as -947.8 +/- 2.2 for tripuhyite and -1061.2 +/- 4.4 for schafarzikite. The accuracy of the data sets was tested by entropy estimates and calculation of Delta H-f degrees from estimated lattice energies (via Kapustinskii equation). Measurements of C-p above T = 300 K were augmented by extrapolation to T = 700 K with the frequencies of acoustic and optic modes, using the Kieffer C-p model. A set of equilibrium constants (log K) for tripuhyite, schafarzikite, and several related phases was calculated and presented in a format that can be employed in commonly used geochemical codes. Calculations suggest that tripuhyite has a stability field that extends over a wide range of pH-p epsilon conditions at T = 298.15 K. Schafarzikite and hydrothermal oxides of antimony (valentinite, kermesite, and senarmontite) can form by oxidative dissolution and remobilization of pre-existing stibnite ores.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10504 - Mineralogy

Projekt

—

Návaznosti

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Rok uplatnění

2023

Kód důvěrnosti údajů

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

Název periodika

Physics and Chemistry of Minerals

ISSN

0342-1791

e-ISSN

1432-2021

Svazek periodika

50

Číslo periodika v rámci svazku

3

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

11

Strana od-do

—

Kód UT WoS článku

001043337700001

EID výsledku v databázi Scopus

2-s2.0-85167414053