Magnesioferrite

Formula : MgFe2O4

Family: 
Oxides
Space group: 
Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F d3m
Dana class: 
7.2.2.1 (7) Multiple Oxides (7.2) (A+ B++)2 X4 Spinel group (7.2.2) (Iron subgroup)
High temperature: 
Experiments of burning coal show that magnesioferrite is stable from 850C to 1100C.
Geological context: 
Occurs in contact metasomatic haloes related with intrusions. It occurs also in coal residues.

Dernière mise à jour le 25.01.2021

THERMODYNAMICS

Individual properties (298.15 K)
M
g·mol-1
 V°
cm3·mol-1
 ΔGºf
J·mol-1
 ΔHºf
J·mol-1
 Sº
J·mol-1·k-1
 CP
J·mol-1·K-1
199.997 43.990 (Ref.: 73bar/kna) Barin I. and Knacke O., 1973, Thermochemical Properties of Inorganic Substances. Berlin: Springer-Verlag. -1326602 (Ref.: Internal calculation) -1438041 (Ref.: 73bar/kna) Barin I. and Knacke O., 1973, Thermochemical Properties of Inorganic Substances. Berlin: Springer-Verlag. 123.846 (Ref.: 73bar/kna) Barin I. and Knacke O., 1973, Thermochemical Properties of Inorganic Substances. Berlin: Springer-Verlag. 138.08 (Ref.: 73bar/kna) Barin I. and Knacke O., 1973, Thermochemical Properties of Inorganic Substances. Berlin: Springer-Verlag.
CP(T) = a + b·T + ·c·T-2 (T in Kelvin)
a
J·mol-1·K-1
 b * 103
J·mol-1·K-2
 c * 10-5
J·K·mol-1
 Maier Kelley Ref.
128.32 32.72 0.00 (Ref.: 73bar/kna) Barin I. and Knacke O., 1973, Thermochemical Properties of Inorganic Substances. Berlin: Springer-Verlag.
Reaction properties

Magnesioferrite + 8H+ ⇌ 2Fe+3 + Mg+2 + 4H2O

298.15 K, 1 bar log10K: 19.26 ΔH°r:-270279 J·mol-1 (Ref.: 73bar/kna) Barin I. and Knacke O., 1973, Thermochemical Properties of Inorganic Substances. Berlin: Springer-Verlag.
T(°C) 0 25 60 100 150 200 250 300
log10K 23.59 19.26 14.29 9.77 5.29 1.63 -1.55 -4.52
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-1389.365294 -0.215839 85411.450064 497.187846 -3889619.850126