A review of the α-Fe2O3 (hematite) nanotube structure: …
Abstract α-Fe 2 O 3 nanotubes are exceptional one-dimensional transition metal oxide materials with low density, large surface area, promising electrochemical and photoelectrochemical properties, which are widely investigated in lithium-ion batteries, photoelectrochemical devices, gas sensors, and catalysis.
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hematite（）_
N a red, grey, or black mineral, found as massive beds and in veins and igneous rocks. It is the chief source of iron. Composition: iron (ferric) oxide. Formula: Fe2O3. Crystal structure: hexagonal (rhombohedral) (Also called iron glance) [1] Red Hematite ; ; Jet hematite argillaceous hematite
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Catalysts | Free Full-Text | Natural Hematite as a Low-Cost …
Developing cheap electrocatalysts for cathodic oxygen reduction in neutral medium is a key factor for practical applications of microbial fuel cells (MFCs). Natural hematite was investigated as a low-cost cathode to improve the performance of microbial fuel cells (MFCs). With hematite-coated cathode, the cell current density stabilized at 330.66 ± 3.1 mA·m−2 (with …
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Ultrathin-Layer a-Fe2O3 Deposited Under Hematite for …
It was found that the α-Fe 2 O 3 (A)/ α-Fe 2 O 3 (B) structure exhibits a higher photoelectrochemical activity when compared to α-Fe 2 O 3 (A) and a-Fe 2 O 3 (B) thin films. The highest photocurrent density was obtained for α-Fe 2 O 3 …
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Hematite | CAS#: | Chemsrc
Section 1: Product Identification Chemical Name:Iron (III) oxide, red (Hematite) (99.8%-Fe) CAS Registry Number: Formula:Fe2O3 EINECS Number:215-275-4 Chemical Family:metal oxide Synonym:Haematite, Iron ore. Red iron oxide. Ferric oxide. Section 2: Composition and Information on Ingredients IngredientCAS NumberPercentACGIH …
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REFINEMENT OF THE HEMATITE STRUCTURE R. L. Blarn …
Pauling and Hendricks (1925) determined the crystal structure of hematite, a-Fe2O3, without using absorption and Lorentz-poiarization corrections and atomic scattering factors, which were not well understood at that time. The structure postulated by them was re-examined before proceeding on the current refinement study of hematite. rnitial ...
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Hematite Mineral Data
General Hematite Information Chemical Formula: Fe2O3 Composition: Molecular Weight = 159.69 gm Iron 69.94 % Fe 100.00 % Fe 2 O 3 Oxygen 30.06 % O ______ ______ 100.00 % 100.00 % = TOTAL OXIDE Empirical Formula: Fe 3+2 O 3 Environment: Magmatic, hydrothermal, metamorphic and sedimentary. IMA Status: Valid Species (Pre-IMA) Prehistoric Locality:
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Hematite | Fe2O3
Hematite | Fe2O3 | CID 14833 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, …
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Schematic illustration of the crystal structure of …
The hematite structure has two formula units per unit cell, the trigonal-hexagonal and the primitive rhombohedral unit cells (Fig. 2). 33 It contains iron and oxygen atoms arranged in a...
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Hematite – Virtual Museum of Molecules and Minerals
N a red, grey, or black mineral, found as massive beds and in veins and igneous rocks. It is the chief source of iron. Composition: iron (ferric) oxide. Formula: Fe2O3. Crystal structure: …
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Hematite
Hematite (α-Fe 2 O 3, the "α-" is omitted henceforth) has the corundum crystal structure, with lattice constants of a = 504 pm and c = 1375 pm. 1 In this structure, layers of distorted …
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Surface Structure and Environment-Dependent …
Hematite (α-Fe 2 O 3) nanoparticles are typically synthesized, stored, or used in hydrous environments, and the mineral/water interfaces are important for the surface stability …
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Hematite: Mineral information, data and localities.
A reniform (kidney-shaped) or botryoidal variety of hematite. The internal structure of the kidney-shaped nodules is usually concentric and radiating. Martite: The name given for hematite …
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Refinement of the hematite structure | Semantic Scholar
A refined monoclinic structure for a variety of "hydrohematite" K. Peterson, P. Heaney, J. Post, P. Eng Geology 2015 Abstract In ferruginous soils, nano- to microscale hematite (α-Fe2O3) plays a central role in redox processes and contaminant cycling. Hematite is known to incorporate structural OH- and water, and… Expand 17 Highly Influenced
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Hydrothermal Precipitation of Sanidine (Adularia) Having …
Hematite (structure confirmed by Rietveld refinement) is the predominant Fe-bearing phase detected. Coarse size fractions of powdered hematite-rich breccia (500–1000 μm) are dark and spectrally neutral at visible wavelengths, confirming specular hematite, and SEM images show platy to polyhedral hematite morphologies with longest dimensions >10 μm.
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Hematite
The structure is similar to that of corundum, and consists essentially of a dense arrangement of Fe 3+ ions in octahedral coordination with oxygens in hexagonal closest …
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Hematite (The Bloodstone Ore)
Hematite formula is Fe 2 O 3, is a simple iron III oxide. Hematite is a member of the trigonal crystal system, exhibiting a large variety of forms. As discrete forms, hematite may occur as small plates or thin splinters. As larger …
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Hematite Nanospheres of Possible Colloidal Origin from a …
Exceptionally small spheres (nanospheres) of hematite (diameters between 120 and 200 nanometers) occur in the Marra Mamba Iron Formation of the Hamersley Basin, Australia. The nanospheres are clustered into small aggregates and may have formed by structural ordering and dehydration of colloidal iron hydroxide particles.
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Hematite | Definition, Uses, & Facts | Britannica
hematite, also spelled haematite, heavy and relatively hard oxide mineral, ferric oxide (Fe 2 O 3 ), that constitutes the most important iron ore because of its high iron content (70 percent) and its abundance. Its name is derived from the …
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Low‐Temperature Activation of Hematite Nanowires for
Hematite (α-Fe 2 O 3) nanostructures have been extensively studied as photoanode materials for photoelectrochemical (PEC) water oxidation. However, the photoactivity of pristine hematite nanostructures is fairly low and typically requires thermal activation at temperature of 650 °C or above.
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The band structure and optical absorption of …
In an effort to better understand the light absorption properties of hematite, in this work we perform a theoretical first-principles investigation of its band structure and optical absorption properties. We use state-of-the-art many …
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Structural, optical, magnetic and electrical properties of …
Preparation of hematite (α-Fe 2 O 3) nanoparticles via polyol method First, 4.054 g of FeCl 3 ·6H 2 O was dissolved in 150 ml of ethylene glycol (EG) with vigorous stirring. 0.9 g of polyvinylpyrrolidone (PVP) was then added dropwise to the stirring mixture.
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Refinement of the hematite structure | American …
The structure has been refined with a least-squares program, and the final structure gave an R-factor of 3.65 per cent. The structure model of Pauling and Hendricks has been confirmed with …
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Earth's Oldest Stromatolites and New Prospects for the …
Stromatolites, layered organo-sedimentary structures that reflect complex interactions between microbial communities and their environment, have long been regarded as crucial macrofossils for detecting life in ancient sedimentary rocks; however, the biological origin of ancient stromatolites has been extensively disputed.
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Structure and properties of vanadium (V)-doped hexagonal turbostratic birnessite and its enhanced scavenging of Pb2+from solutions. Journal of Hazardous Materials, 2015, 288: 80-88. (SCI,...
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Atomic-Scale Structure of the Hematite α-Fe2O3(11̅02) "R …
Both (11̅02) hematite surfaces, (1 × 1) and (2 × 1), were modeled by fully relaxed slabs without inversion symmetry and a vacuum of 19 Å. These slabs contain five Fe 2 O 3 units as depicted in Figure 1 (b), with five atomic layers (three oxygen and two iron layers) within every unit (labeled 1–5 in Figure 1 ).
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Hematite | Definition, Uses, & Facts | Britannica
hematite, also spelled haematite, heavy and relatively hard oxide mineral, ferric oxide (Fe 2 O 3), that constitutes the most important iron ore because of its high iron content (70 percent) and its abundance. Its name is derived from the …
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Iridescence in Metamorphic "Rainbow" Hematite | Gems
For the hematite refinement, we incorporated the peak profile parameters refined for LaB6, and the initial structure parameters for hematite came from Blake et al. (1966). Using a 2θ range of 11.5° to 37.5° (d hkl = 4.1 Å to 1.3 Å), we refined the background using a cosine Fourier series polynomial with eight profile terms.
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Hematite structure
Hematite structure The structure of ferrihydrite has been the object of numerous studies in the past and several different structures have been proposed. The main difficulty affecting elucidation of the structure is the low degree of order. The original models of Towe and Bradley ...
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Nano-structural effects on Hematite (α-Fe2O3) …
We confirmed the as-synthesized hematite nanoparticles had the α-Fe 2 O 3 crystal structure through x-ray diffractometry. 28 2θ of 24.2°, 33.2°, 35.6°, 40.9°, and 49.4° corresponding to α-Fe 2 O 3, are shown in the XRD patterns in Fig. 1.
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57Fe Möss spectroscopic study on the magnetic …
Hematite is n-type semiconductor with low band gap energy (about 2.2 eV) and the crystal structure belongs to rhombohedral [ 5 ]. It is the most stable form among iron oxides as the final product of iron oxide transformation [ 6 ]. The oxygen ions are arranged in a hexagonal close-packed structure with Fe 3+ ions occupying octahedral sites [ 7 ].
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