Transformations of ferrates(IV,V,VI) in liquids: Mossbauer spectroscopy of frozen solutions

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61988987%3A17310%2F18%3AA1901WM9" target="_blank" >RIV/61988987:17310/18:A1901WM9 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61989592:15310/18:73589823

Výsledek na webu

<a href="http://dx.doi.org/10.1039/c8cp05952g" target="_blank" >http://dx.doi.org/10.1039/c8cp05952g</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c8cp05952g" target="_blank" >10.1039/c8cp05952g</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Transformations of ferrates(IV,V,VI) in liquids: Mossbauer spectroscopy of frozen solutions

Popis výsledku v původním jazyce

The kinetics and mechanism of ferrate(IV), (V) and (VI) transformations in water and in polar organic solvents (namely ethanol and tetrahydrofuran) have been investigated by the method of 57Fe Mo ?ssbauer spectroscopy of frozen solutions. Ethanol with a very limited amount of water under an inert atmosphere, significantly slows down the transformation reactions of ferrates(IV and V) and provides direct proof of the existence of intermediate states. Simultaneously, ethanol is oxidized to caboxylates in the close vicinity of the surface of ferrate crystallites as proven by X-ray photoelectron spectroscopy. On the contrary, any transformation of ferrate(VI) in pure ethanol (with a very limited amount of water) was not observed. Mo ?ssbauer spectroscopy of frozen solutions enabled us to experimentally identify and quantify intermediates of ferrate(IV) and ferrate(V) transformations for the first time. Sodium ferrate(IV) in its tetrahedral form, Na4FeO4, undergoes a two-step charge disproportionation to Fe(III) and Fe(VI) via a Fe(V) intermediate without any evolution of oxygen in polar protic and aprotic solvents, specifically 2Fe(IV) - Fe(III) + Fe(V), and Fe(IV) + Fe(V) - Fe(III) + Fe(VI), i.e. in sum 3Fe(IV) - 2Fe(III) + Fe(VI). Ferrate(V) (K3FeO4) transforms to Fe(III) and Fe(VI) without any indication of the Fe(IV) intermediate within the detection limit of the method. In addition to a charge disproportionation reaction proceeding in polar liquids, 3Fe(V) - Fe(III) + 2Fe(VI), a competitive reduction of Fe(V) directly to Fe(III) accompanied by oxygen evolution takes place in water. Oxygen evolution was also measured for ferrate(IV and VI) transformations in water, but to a higher and a smaller extent compared to ferrate(V), respectively. The thermodynamics of the suggested ferrate(IV) and ferrate(V) transformation pathways was examined by DFT calculations.

Název v anglickém jazyce

Transformations of ferrates(IV,V,VI) in liquids: Mossbauer spectroscopy of frozen solutions

Popis výsledku anglicky

The kinetics and mechanism of ferrate(IV), (V) and (VI) transformations in water and in polar organic solvents (namely ethanol and tetrahydrofuran) have been investigated by the method of 57Fe Mo ?ssbauer spectroscopy of frozen solutions. Ethanol with a very limited amount of water under an inert atmosphere, significantly slows down the transformation reactions of ferrates(IV and V) and provides direct proof of the existence of intermediate states. Simultaneously, ethanol is oxidized to caboxylates in the close vicinity of the surface of ferrate crystallites as proven by X-ray photoelectron spectroscopy. On the contrary, any transformation of ferrate(VI) in pure ethanol (with a very limited amount of water) was not observed. Mo ?ssbauer spectroscopy of frozen solutions enabled us to experimentally identify and quantify intermediates of ferrate(IV) and ferrate(V) transformations for the first time. Sodium ferrate(IV) in its tetrahedral form, Na4FeO4, undergoes a two-step charge disproportionation to Fe(III) and Fe(VI) via a Fe(V) intermediate without any evolution of oxygen in polar protic and aprotic solvents, specifically 2Fe(IV) - Fe(III) + Fe(V), and Fe(IV) + Fe(V) - Fe(III) + Fe(VI), i.e. in sum 3Fe(IV) - 2Fe(III) + Fe(VI). Ferrate(V) (K3FeO4) transforms to Fe(III) and Fe(VI) without any indication of the Fe(IV) intermediate within the detection limit of the method. In addition to a charge disproportionation reaction proceeding in polar liquids, 3Fe(V) - Fe(III) + 2Fe(VI), a competitive reduction of Fe(V) directly to Fe(III) accompanied by oxygen evolution takes place in water. Oxygen evolution was also measured for ferrate(IV and VI) transformations in water, but to a higher and a smaller extent compared to ferrate(V), respectively. The thermodynamics of the suggested ferrate(IV) and ferrate(V) transformation pathways was examined by DFT calculations.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10301 - Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2018

Kód důvěrnosti údajů

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

Název periodika

Physical Chemistry Chemical Physics

ISSN

1463-9076

e-ISSN

1463-9084

Svazek periodika

20

Číslo periodika v rámci svazku

48

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

10

Strana od-do

30247-30256

Kód UT WoS článku

000453231100014

EID výsledku v databázi Scopus

2-s2.0-85058461054