Crystal structure of magnetite under pressure

Nakagiri, Nobuyuki; Manghnani, Murli H.; Ming, L. C.; Kimura, Shigeyuki

doi:10.1007/bf00308275

Cited by 124 publications

(48 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The determinations by Gerward and Staun-Olsen (1995) and by StaunOlsen et al (1994) appear to be in agreement with the presently obtained value. A much lower value was obtained by Wilburn and Bassett (1977), whereas intermediate values are reported by Mao et al (1974), Hazen et al (1981), Finger et al (1986), and Nakagiri et al (1986).…”

Section: Crystal Structure and Equation Of State Of Magnetitecontrasting

confidence: 36%

“…The bulk moduli of the cation tetrahedra and octahedra are equal to the bulk modulus characteristic of the entire crystal in agreement with the lower pressure data by Finger et al (1986), see Figure 6. Nakagiri et al (1986) report that tetrahedra and octahedra have different polyhedral bulk moduli values for P < 4.5 GPa; 170 (10) and 200 (8) GPa, respectively. Nine independent studies give bulk modulus values in the range from 155 to 215 GPa (Table 2).…”

Section: Crystal Structure and Equation Of State Of Magnetitementioning

confidence: 97%

“…Furthermore, in that pressure range both the tetrahedra and the octahedra display the bulk modulus characteristic for the unit-cell volume. The oxygen xcoordinate, the only variable atomic position coordinate for the spinel structure, does not vary with pressure for P < 4.5 GPa (Finger et al 1986;Nakagiri et al 1986). …”

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

Equation of state of magnetite and its high-pressure modification: Thermodynamics of the Fe-O system at high pressure

Haavik

Stølen

Fjellvåg

et al. 2000

American Mineralogist

229

171

View full text Add to dashboard Cite

Fe 3 O 4 has been studied by high-pressure diffraction to 43 GPa. No major changes in the spinel-type structure of magnetite is observed below 21.8 GPa. At higher pressure a sluggish transition to a highpressure modification, h-Fe 3 O 4 , is observed. The X-ray diffraction pattern of the high-pressure modification is consistent with the orthorhombic unit cell (CaMn 2 O 4 -type structure, space group Pbcm) recently proposed for h-Fe 3 O 4 by Fei et al. (1999), however, it is also consistent with a more symmetric CaTi 2 O 4 -type structure (space group Bbmm). Bulk modulus values for magnetite, K T0 = 217 (2) GPa, and hFe 3 O 4 , K T0 = 202 (7) GPa, are calculated from the pressure-volume data using a third-order Birch-Murnaghan equation of state. A thermodynamic analysis of the Fe-O system at high pressure is presented. The proposed equation of state of h-Fe 3 O 4 gives an increased stability of wüstite relatively to a two-phase mixture of iron and h-Fe 3 O 4 compared to earlier equations of state and removes an inconsistency in the thermodynamic description of the Fe-O system at high pressure.

show abstract

Section: Crystal Structure and Equation Of State Of Magnetitecontrasting

confidence: 36%

Section: Crystal Structure and Equation Of State Of Magnetitementioning

confidence: 97%

See 1 more Smart Citation

Equation of state of magnetite and its high-pressure modification: Thermodynamics of the Fe-O system at high pressure

Haavik

Stølen

Fjellvåg

et al. 2000

American Mineralogist

229

171

View full text Add to dashboard Cite

show abstract

“…They report bulk moduli of 194 ± 6 for spinel and 186 ± 5 GPa for magnetite. In good agreement with this study, Nakagiri et al (1986) report the structure of magnetite to 4.5 GPa and find a bulk modulus of 181 ± 2 GPa. These results are summarized in Table 10.…”

Section: Ilmenite Group (Abo 3 )supporting

confidence: 75%

Comparative Crystal Chemistry of Dense Oxide Minerals

Smyth

Jacobsen

Hazen

2000

Reviews in Mineralogy and Geochemistry

View full text Add to dashboard Cite

INTRODUCTIONOxygen is the most abundant element in the Earth, constituting about 43 percent by weight of the crust and mantle. While most of this mass is incorporated into silicates, the next most abundant mineral group in the planet is the oxides. The oxide minerals are generally considered to be those oxygen-based minerals that do not contain a distinct polyanionic species such as OH -, CO 3 2-, SO 4 2-PO 4 3-, SiO 4 4-, etc. The oxide structures are also of interest in mineral physics, because, at high pressure, many silicates are known to adopt structures similar to the dense oxides (see Hazen and Finger this volume).Oxide minerals, because of their compositional diversity and structural simplicity, have played a special role in the development of comparative crystal chemistry. Many of the systematic empirical relationships regarding the behavior of structures with changing temperature and pressure were first defined and illustrated with examples drawn from these phases. Oxides thus provide a standard for describing and interpreting the behavior of more complex compounds. Our principal objectives here are to review the mineral structures that have been studied at elevated temperatures and pressures, to compile thermal expansion and compression data for the various structural elements in a consistent fashion, and to explore systematic aspects of their structural behavior at nonambient conditions. The large and growing number of single-crystal structure investigations of the simpler or more important dense oxides at high pressures and temperatures warrant this comparative synthesis.Regarding thermal expansion for various structural elements, we have chosen to assume linear expansion coefficients. This approach facilitates comparison across disparate structures and methodologies, and it reflects the reality that data are not sufficiently precise in many cases to permit the meaningful derivation of second-order thermal expansion parameters. For compression data we have also computed linear axial compressibilities to facilitate comparison of the various axes, but we have retained the pressure derivative of the bulk modulus, K', where refined or assumed the standard value of 4 for K'.The scope of this chapter is dictated by the range of naturally-occurring oxide structure types. Oxide minerals may be divided conveniently into the simple oxides, which contain a single cationic site or species, and the binary oxides, which contain two distinct cationic sites or species. The alkali elements do not occur as simple oxide minerals, so the only natural X 2 O mineral, other than ice (see Chapter 15 by Hemley and Dera in this volume), is cuprite (Cu 2 O). No structural studies have yet been undertaken on cuprite at non-ambient conditions.In contrast to the simple oxides of monovalent cations, many oxide minerals of divalent cations are known, and several of these are of major geophysical significance. Of these minerals, the periclase group with the rocksalt (NaCl) structure are the most widely studied at non-ambient condit...

show abstract

“…P T was determined from the high-pressure equation of state for magnetite reported by Nakagiri et al 17 The thermal expansion coefficient˛ T was taken from Okudera et al 18 in the form˛ T D 2.137 ð 10…”

Section: Quasi-harmonic Approximation For the Shifts Of Wavenumbersmentioning

confidence: 99%