Synthesis, Crystal and Magnetic Structures of the Sodium Ferrate (IV) Na4FeO4 Studied by Neutron Diffraction and Mössbauer Techniques

Oxidation of inorganic contaminants by ferrates (VI, V, and IV)–kinetics and mechanisms: A review

“…Na 4 FeO 4 is isotypic with other known solid phases Na 4 MO 4 (M ¼ Ti, Cr, Mn, Co, Ge, Sn, and Pb) (Jeannot et al, 2002). The structure of Na 4 FeO 4 is characterized as a three-dimensional network of isolated FeO 4 tetrahedra connected by Na atoms.…”

“…Another type of ferrate(IV), Ba 3 FeO 5 was obtained by fusion of Ba 3 [Fe(OH) 6 ] 2 and Ba(OH) 2 in a Fe:Ba ratio of 1:3 at 900 C in oxygen (Delattre et al, 2000). Na 4 FeO 4 (black powder) was obtained by the oxidation of Fe 2 O 3 and Na 2 O mixture in a stream of O 2 at 700e900 C (Jeannot et al, 2002).…”

“…Salts of higher oxidation states of iron ranging from þ4 to þ8 have also been synthesized in laboratory (Atanasov, 1999;Bielski, 1990;Bielski and Thomas, 1987;Dedushenko et al, 2008;Hoppe and Mader, 1990;Jeannot et al, 2002;Kokarovtseva et al, 1972;Kopelev et al, 1990Kopelev et al, , 1992Kopelev, 1997;Perfiliev and Sharma, 2008;Perfiliev et al, 2006;Perfliev, 2002). Ferrate(VI) Fe VI O 2À 4 has been of great interest because of its role as an oxidant and hydroxylating agent in industrial and water treatment processes, such as the development of a "super iron" battery, green chemistry synthesis, and non-chlorine oxidation for pollutant remediation (Bartzatt and Carr, 1986;Carr et al, 1985;Johnson et al, 2008;Hornstein, 1994, 1996;Licht et al, 1999;Licht and Yu, 2008;Sharma, 2002a;Sharma et al, 2005a,b) Ferrate(VI) provides an environmentally benign high energy density cathode for batteries (Licht et al, 2009(Licht et al, , 1999Licht, 2010;Licht and TelVered, 2004).…”

Mössbauer study of iron in high oxidation states in the K–Fe–O system

“…2) are correlated well with the parameters of the sodium ferrate(IV), Na 4 FeO 4 [3,10]. Potassium ferrate(IV), K 4 FeO 4 , could be a product of a parallel reaction, or could be the result of the decomposition of the ferrate(V).…”

Thermodynamic evaluation of sodium ferrite Na4Fe6O11

“…In the (Na + Fe + O) system, about 20 kinds of sodium ferrate [1,2] have been reported in the literature among them, oxides with unusual high iorn oxidation states, such as +4, that are not normally stable and tend to decompose to a lower valence state [3]. Sodium ferrite (Na 4 Fe 6 O 11 or Na 2 O1 AE 5Fe 2 O 3 ) was studied in 1950s [4][5][6].…”