.alpha.- and .beta.-ferric fluoride trihydrate revisited: crystal structure and iron-57 Moessbauer spectra

Computational Determination of Iron Hyperfine Interactions in Organometallics Using Small Transverse External Magnetic Fields

“…As a test case for the procedure, a sample of FeF 2 , containing an impurity (probably FeF 3 ·3H 2 O ≈ 10 %), whose hyperfine interaction parameters are known, [8,9] has been studied. The spectra in zero external magnetic field and in an external field of 2.13 T are displayed in Figure 3.…”

“…Using the known starting parameters (isomer shift, quadrupole interaction, and saturation magnetic hyperfine field) of both Table 1. FeF 2 and FeF 3 ·3H 2 O (averaged over the two phases [9] ), we obtain, from the computer least-square fit, the solid curve shown in the lower trace of Figure 3. The fit to the experimental spectrum is quite satisfactory, and the numerical data, including the hyperfine parameters η, H eff , and H hf , are summarized in Table 1.…”

“…In addition, the application of a complete diagonalization program of the full Hamiltonian for powder samples averaging over all possible random orientations makes it possible to extract the internal hyperfine field in both diamagnetic and paramagnetic complexes. 2 ] was prepared by literature methods [9] and its purity was checked by FTIR measurements. Sodium nitroprusside [Na 2 Fe(CN) 5 NO·2H 2 O] [10] was taken from high-purity single-crystal material.…”

“…For µ B H ext /kT ϽϽ 1, one can write the simple approximate relation (9): (9) Namely, the effective field acting on the nucleus is given now by (10): (10) In the cases where the magnetic ion has a ground-state Kramers doublet with an effective spin S = ½, common in the magnetic organometallics, formula (10) obtains the form (11): (11) where in powders g eff = 1 ͞ 3 g ʈ + 2 / 3 g Ќ and H hfa is a similar average of H hf . Thus a measurement of a paramagnetic compound in an external magnetic field may yield the average value of H hf with its sign (12):…”

Iron fluorides assisted dehydrogenation and hydrogenation of MgH2 studied by Mössbauer spectroscopy

“…Ferric fluoride is contaminated by similar oxide, albeit much better ordered. Additionally, it exhibits some degree of hydration [12]. Figures (a-c) show spectra for the FeF2 doped material upon milling, dehydrogenation and hydrogenation, respectively.…”