scholarly journals Discovery of Fe7O9: a new iron oxide with a complex monoclinic structure

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Ryosuke Sinmyo ◽  
Elena Bykova ◽  
Sergey V. Ovsyannikov ◽  
Catherine McCammon ◽  
Ilya Kupenko ◽  
...  
Keyword(s):  
Applied Sciences ◽  
Crystal Structure ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Industrial Applications ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure High Temperature ◽  
Insight Into

Abstract Iron oxides are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary iron oxide with the hitherto unknown stoichiometry of Fe7O9. This new oxide was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 adopts a monoclinic C2/m lattice with the most distorted crystal structure among the binary iron oxides known to date. The synthesis of Fe7O9 opens a new portal to exotic iron-rich (M,Fe)7O9 oxides with unusual stoichiometry and distorted crystal structures. Moreover, the crystal structure and phase relations of such new iron oxide groups may provide new insight into the cycling of volatiles in the Earth’s interior.

scholarly journals High-pressure synthesis and crystal structure of the mixed-cation borate Ga4In4B15O33(OH)3

2019 ◽  
Vol 74 (4) ◽  
pp. 357-363
Author(s):  
Daniela Vitzthum ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Mixed Cation ◽  
High Pressure High Temperature ◽  
Pressure Synthesis

AbstractThe mixed cation triel borate Ga4In4B15O33(OH)3 was synthesized in a Walker-type multianvil apparatus at high-pressure/high-temperature conditions of 12.5 GPa and 1300°C. Although the product could not be reproduced in further experiments, its crystal structure could be reliably determined via single-crystal X-ray diffraction data. Ga4In4B15O33(OH)3 crystallizes in the tetragonal space group I41/a (origin choice 2) with the lattice parameters a = 11.382(2), c = 15.244(2) Å, and V = 1974.9(4) Å3. The structure of the quaternary triel borate consists of a complex network of BO4 tetrahedra, edge-sharing InO6 octahedra in dinuclear units, and very dense edge-sharing GaO6 octahedra in tetranuclear units.

scholarly journals The Influence of Synthesis Parameters on Structural and Magnetic Properties of Iron Oxide Nanomaterials

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 85 ◽  
Author(s):  
Laura Madalina Cursaru ◽  
Roxana Mioara Piticescu ◽  
Dumitru Valentin Dragut ◽  
Ioan Albert Tudor ◽  
Victor Kuncser ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Crystalline Phase ◽  
Annealing Treatment ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Order Of Magnitude

Magnetic iron oxides have been used in biomedical applications, such as contrast agents for magnetic resonance imaging, carriers for controlled drug delivery and immunoassays, or magnetic hyperthermia for the past 40 years. Our aim is to investigate the effect of pressure and temperature on the structural, thermal, and magnetic properties of iron oxides prepared by hydrothermal synthesis at temperatures of 100–200 °C and pressures of 20–1000 bar. It has been found that pressure influences the type of iron oxide crystalline phase. Thus, the results obtained by Mössbauer characterization are in excellent agreement with X-ray diffraction and optical microscopy characterization, showing that, for lower pressure values (<100 bar), hematite is formed, while, at pressures >100 bar, the major crystalline phase is goethite. In addition, thermal analysis results are consistent with particle size analysis by X-ray diffraction, confirming the crystallization of the synthesized iron oxides. One order of magnitude higher magnetization has been obtained for sample synthesized at 1000 bar. The same sample provides after annealing treatment, the highest amount of good quality magnetite leading to a magnetization at saturation of 30 emu/g and a coercive field of 1000 Oe at 10 K and 450 Oe at 300 K, convenient for various applications.

scholarly journals Synthesis of an Anticorrosive Pigment by Thermal Treatment of Iron Oxides from Steel Industry Wastes

2019 ◽  
Vol 28 (52) ◽  
pp. 43-58
Author(s):  
María Angélica Colpas-Ruiz ◽  
Camilo Gnecco-Molina ◽  
Gabriel Antonio Jiménez-Rodríguez ◽  
José Andrés Pérez-Mendoza ◽  
Óscar Fabián Higuera-Cobos
Keyword(s):  
Iron Oxide ◽  
Thermal Treatment ◽  
Iron Oxides ◽  
Steel Industry ◽  
Powder Steel ◽  
Total Iron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Industry Waste ◽  
Different Temperatures

This work reports the obtaining of an anticorrosive pigment composed mainly of hematite (ɑ-Fe2O3) from a powder steel industry waste from rust scale of rebar steel. This residue is mainly composed of Fe2O3 (87.97 %), SiO2 (6.13 %), CaO (1.88 %), Al2O3 (1.30%) and MnO (0.77 %). The total iron oxide of the residue is constituted by the following crystalline phases: magnetite, maghemita, lepidocrocita, wüstite, goethite and hematite. The production of a pigment with a high content of hematite was possible thanks to the high content of precursor iron oxides, which were calcined at different temperatures (750-850 °C) and holding times (0.5-1.50 h). For characterizing the iron content chemically and to identify their iron oxides phases, it was used X-ray fluorescence (XRF) and X-ray diffraction (XRD). The results showed that the pigment with the highest amount of hematite (ɑ-Fe2O3) was obtained at a calcination temperature of 850 °C and a holding time of 1.00 h.

scholarly journals Compressional Behavior of Hydrous Orthoenstatite: Insight into the Nature of LVZ under Continental Plate

Minerals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 71
Author(s):  
Florian Tian-Siang Hua ◽  
Przemyslaw Dera ◽  
Jennifer Kung
Keyword(s):  
Crystal Structure ◽  
Upper Mantle ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Low Velocity ◽  
X Ray ◽  
Low Level ◽  
Al Content ◽  
Continental Plate ◽  
Influence Of Water

A suite of hydrous orthoenstatite crystals were synthesized at 5–7 GPa and 1100–1300 °C, corresponding to the mid upper mantle conditions in continental regions. The synthetic crystals presented a clear, inclusion-free, and euhedral form with a size range from 100 to a few hundred microns. The Al- and water content of crystals were less than 2 wt. % and ranging from ~500 ppm to 1000 ppm, respectively, characterized by Raman and IR spectroscopy, electron microscopy, and SIMS. The analysis shows that the capability of water incorporation for this suite of hydrous orthoenstatite is correlated to the Al-content in the crystal structure. To understand how the detailed crystal structure reflects the influence of water and Al, single crystal X ray diffraction analysis was performed for this suite of hydrous orthoenstatite. By comparing the results obtained at ambient conditions, we find that for low-level of Al-content, <2 wt. %, the Al3+ cation tends to occupy one of tetrahedral sites (TB) only. Analysis of the X ray diffraction results under high pressure indicates that the elasticity of orthoenstatites is insensitive to the presence of low-level water and Al. We use this finding to evaluate the velocity profile at the mid upper mantle of continental regions to compare with seismic observation. The comparison indicates that the cause of the low velocity zone in continental regions originates from the geotherm profile rather than the effect of water on the elasticity of mantle phases.

Charge properties of red Argentine soils as an indicator of iron oxide/clay associations

Soil Research ◽  
2001 ◽  
Vol 39 (2) ◽  
pp. 423 ◽  
Author(s):  
R. M. Torres Sánchez ◽  
M. Okumura ◽  
R. C. Mercader
Keyword(s):  
Iron Oxide ◽  
Iron Oxides ◽  
Photoelectron Spectroscopy ◽  
Electron Probe ◽  
Surface Coverage ◽  
Oxide Coating ◽  
Point Of Zero Charge ◽  
X Ray Diffraction ◽  
X Ray ◽  
North Eastern

The order of the relative degree of iron oxide coating of 4 samples of red soils from north-eastern Argentina was established using the point of zero charge (PZC), yielded by potentiometric titration, and the isoelectric point (IEP), obtained from the diffusion potential. When PZC is different from IEP, the relative fraction of apparent surface coverage could be assessed from the IEP. The results obtained by the application of X-ray diffraction, scanning electron microscopy, electron probe microanalysis, X-ray photoelectron spectroscopy, M&ouml;ssbauer spectroscopy, and specif ic surface area, although essential to characterise the samples, did not allow us to determine the degree of iron oxide coating. Our findings show that the order of this degree is opposite to the order of the ratio of the amount of free iron oxides to that of clay in iron oxides/clay mixtures.

High-pressure Synthesis and Crystal Structure of the Vanadium Orthoborate VBO3

2008 ◽  
Vol 63 (6) ◽  
pp. 713-717 ◽  
Author(s):  
Almut Haberer ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Oxygen Coordination ◽  
High Pressure High Temperature ◽  
Distorted Octahedral ◽  
Pressure Synthesis ◽  
Octahedral Oxygen

The vanadium orthoborate VBO3 was synthesized under high-pressure / high-temperature conditions of 7.5 GPa and 1250 °C in a Walker-type multianvil apparatus. The crystal structure was determined on the basis of single crystal X-ray diffraction data, collected at r. t. The title compound crystallizes in the trigonal calcite structure, space group R3̄c, with the lattice parameters a = 462.0(1) and c = 1450.9(3) pm. Within the trigonal planar BO3 groups, the B-O distance is 138.8(3) pm. The vanadium atoms have a slightly distorted octahedral oxygen coordination (V-O: 202.3(2) pm).

Consolidation of Mg2Si Powder Using Shockwave Generated by Projectile Impact

2013 ◽  
Vol 767 ◽  
pp. 177-182 ◽  
Author(s):  
Hiroaki Kishimura ◽  
Yuki Yano ◽  
Hitoshi Matsumoto
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Milled Powder ◽  
Shock Pressure ◽  
Original Structure ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Shock Compaction ◽  
Phase Transition Pressure

A series of shock compaction experiments on as-received and ball-milled Mg2Si powder were conducted. The crystalline size in the shocked compacts obtained from the ball-milled powder was equivalent to that of the compacts obtained from the as-received powder. Although the shock pressure was higher than the phase transition pressure, the crystal structure reverted to its original structure under ambient conditions. For the shocked compact obtained from the ball-milled powder, a MgO peak appeared in the X-ray diffraction pattern.

scholarly journals The untypical high-pressure Zintl phase SrGe6

2020 ◽  
Vol 75 (1-2) ◽  
pp. 209-216 ◽  
Author(s):  
Ulrich Schwarz ◽  
Rodrigo Castillo ◽  
Julia M. Hübner ◽  
Aron Wosylus ◽  
Yurii Prots ◽  
...  
Keyword(s):  
High Pressure ◽  
Ambient Pressure ◽  
Three Dimensional ◽  
Structure Type ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Quantum Chemical Analysis ◽  
Electronic Density ◽  
X Ray ◽  
High Pressure High Temperature

AbstractThe binary strontium germanide SrGe6 was synthesized at high-pressure high-temperature conditions of approximately 10 GPa and typically 1400 K before quenching to ambient conditions. At ambient pressure, SrGe6 decomposes in a monotropic fashion at T = 680(10) K into SrGe2 and Ge, indicating its metastable character. Single-crystal X-ray diffraction data indicate that the compound SrGe6 adopts a new monoclinic structure type comprising a unique three-dimensional framework of germanium atoms with unusual cages hosting the strontium cations. Quantum chemical analysis of the chemical bonding shows that the framework consists of three- and four- bonded germanium atoms yielding the precise electron count Sr[(4bGe0]4[(3b)Ge−]2 in accordance with the 8 − N rule and the Zintl concept. Conflicting with that, a pseudo-gap in the electronic density of states appears clearly below the Fermi level, and elaborate bonding analysis reveals additional Sr–Ge interactions in the concave coordination polyhedron of the strontium atoms.

High-pressure synthesis and crystal structure of In3B5O12

2017 ◽  
Vol 72 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Daniela Vitzthum ◽  
Michael Schauperl ◽  
Klaus R. Liedl ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
High Pressure High Temperature ◽  
Pressure Synthesis ◽  
Ir And Raman

AbstractOrthorhombic In3B5O12 was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 12.2 GPa and 1500°C. Its structure is isotypic to the rare earth analogs RE3B5O12 (RE=Sc, Er–Lu). In the field of indium borate chemistry, In3B5O12 is the third known ternary indium borate besides InBO3 and InB5O9. The crystal structure of In3B5O12 has been determined via single-crystal X-ray diffraction data collected at room temperature. It crystallizes in the orthorhombic space group Pmna with the lattice parameters a=12.570(2), b=4.5141(4), c=12.397(2) Å, and V=703.4(2) Å3. IR and Raman bands of In3B5O12 were theoretically determined and assigned to experimentally recorded spectra.

scholarly journals Synthesis and Crystal Structure of the Praseodymium Orthoborate λ -PrBO3

2010 ◽  
Vol 65 (10) ◽  
pp. 1206-1212 ◽  
Author(s):  
Almut Haberer ◽  
Reinhard Kaindl ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Diffraction Data ◽  
Title Compound ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
High Pressure High Temperature

The praseodymium orthoborate λ -PrBO3 was synthesized from Pr6O11, B2O3, and PrF3 under high-pressure / high-temperature conditions of 3 GPa and 800 °C in a Walker-type multianvil apparatus. The crystal structure was determined on the basis of single-crystal X-ray diffraction data, collected at room temperature. The title compound crystallizes in the orthorhombic aragonite-type structure, space group Pnma, with the lattice parameters a = 577.1(2), b = 506.7(2), c = 813.3(2) pm, and V = 0.2378(2) nm3, with R1 = 0.0400 and wR2 = 0.0495 (all data). Within the trigonal-planar BO3 groups, the average B-O distance is 137.2 pm. The praseodymium atoms are ninefold coordinated by oxygen atoms.

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