Fe2P2O7 and Fe2P4O12 studied between 5–800 K

Low temperature heat capacity Study of Fe(PO3)3 and Fe2P2O7

“…However, it can be noticed in the insets of figures 1 and 2 that there is a phase transition taking place at around T = 10 K for Fe(PO 3 ) 3 and 20 K for Fe 2 P 2 O 7 . The magnetic measurements reported for these materials suggest the phase transitions involved for both of these iron phosphate compounds are antiferromagnetic [28,[30][31][34][35][36].…”

“…Fe 2 P 2 O 7 is an important iron phosphate which is often used as a catalyst for oxidative dehydrogenation, a food additive for anemia, a supporting medium in solid lubricant and an ingredient for a sort of pigment F-P-Fe [29]. Ericsson et al have studied the magnetic properties of Fe 2 P 2 O 7 using Mössbauer spectra which suggests the existence of a magnetic transition taking place at about 21 K [30], while the magnetic measurement performed by Parada et al revealed it to be an antiferromagnetic transition at about 12.5 K [31]. To verify this magnetic behavior and transition temperature, it is necessary to study the heat capacity of this compound which has not been reported until now.…”

Graphite immobilisation in iron phosphate glass composite materials produced by microwave and conventional sintering routes

“…Fe 2+ and Fe 3+ were assigned by considering the work of Darby-Dyar et al [26]. Mössbauer parameters from the literature for iron phosphate glasses [27], FeP 2 O 6 [28], Fe(PO 3 ) 3 [29] and Fe 2 (P 2 O 6 ) [28,30] were used as references in the fitting. The magnetite used in this work matched with pdf card 19-629, and contained 69% Fe 3+ and 31% Fe 2+ .…”

A vibrational study of phase transitions in Fe2P2O7 and Cr2P2O7 under high‐pressures

“…Each of these phases show polymorphism at ambient pressures and variable temperatures: following crystallizing from an oxalate/hydrated/ammoniated liquid at 700°C, Fe 2 P 2 O 7 crystallizes in the monoclinic P2 1 /c space group, and at ~20 K, it magnetically orders . For comparison, Cr 2 P 2 O 7 undergoes an incommensurate to commensurate transition near 285 K …”

“…5,14 Each of these phases show polymorphism at ambient pressures and variable temperatures: following crystallizing from an oxalate/hydrated/ammoniated liquid at 700°C, Fe 2 P 2 O 7 crystallizes in the monoclinic P2 1 /c space group, 15 and at~20 K, it magnetically orders. 16,17 For comparison, Cr 2 P 2 O 7 undergoes an incommensurate to commensurate transition near 285 K. 7 Here, we probe the responses of these two structures to compression using vibrational spectroscopy. The present study represents a continuation of our previous investigations on phosphates.…”