chromite crystal structure

8.6: Spinel, perovskite, and rutile structures - Chemistry ...

1 1 First crystal-structure determination of chromites from an 2 acapulcoite and ordinary chondrites 3 Davide Lenaz1*, Francesco Princivalle1 and Birger Schmitz2,3 4 5 1Department of Mathematics ...

The structure of and origin of nodular chromite from the ...

REFERENCES for Chromite; American Mineralogist Crystal Structure Database Record: [view record] Anthony J W, Bideaux R A, Bladh K W, and Nichols M C (1990) Handbook of Mineralogy, Mineral Data Publishing, Tucson Arizona, USA, by permission of the Mineralogical Society of America.

Synthesis and crystal structure of chromium-bearing ...

Chromite is an iron chromium oxide: FeCr 2 O 4.It is an oxide mineral belonging to the spinel group.Magnesium can substitute for iron in variable amounts as it forms a solid solution with magnesiochromite (MgCr 2 O 4); substitution of aluminium occurs leading to hercynite (FeAl 2 O 4).

Chromite - Revolvy

Crystal structure of spinel In chemistry the term chromite has been used in two contexts. Under IUPAC naming conventions, chromate(III) is preferred to chromite. For compounds containing an oxyanion of chromium in oxidation state 3 For other compounds of chromium(III) as a means of distinguishing a chemical species such as hexacyanochromite(III).

Chromite R110059 - RRUFF Database: Raman, X-ray, Infrared ...

Western University. [email protected] Electronic Thesis and Dissertation Repository February 2015 Chromite Crystal Structure and Chemistry applied

Chromite R110059 - RRUFF Database: Raman, X-ray, Infrared ...

structural, optical and magnetic characterization of spinel zinc chromite (zncr 2 o 4) nanocrystals synthesized by thermal treatment method. by adamu salahudeen gene

chromites - an overview | ScienceDirect Topics

Chromite spinels, M II Cr 2 O 4, are always normal spinelsbecause the d 3 Cr 3+ ion has a strong preference for the octahedral site. ... The mineral rutile is one of the polymorphs of TiO 2, the others (anatase and brookite) also being 6:3 structures. Figure: Rutile crystal lattice.

STRUCTURAL, OPTICAL AND MAGNETIC …

Chromite which contained higher levels of Cr(VI), was found to be mutagenic in Salmonella typhimurium. ECOTOXICITY STUDIES: Hexavalent chromium [Cr (VI)] is a constituent of chromite ore. Although it is known to have several industrial and technological applications, its release into the aquatic environment as a result of chemical spill or ...

Magnesiochromite Mineral Data

Mar 01, 2012· Rietveld analysis of XRD data showed that the studied samples presented the lanthanum chromite with an orthorhombic structure (Pnma), except for the composition with x=0.30, in which the space group was found to be R 3 c.

First crystal-structure determination of chromites from an ...

Abstract. A chromium-bearing wadsleyite (Cr-Wad) was synthesized in the model system Mg 2 SiO 4 –MgCr 2 O 4 at 14 GPa and 1600 °C and studied from the chemical and structural point of views.Microprobe data gave the formula Mg 1.930 Cr 0.120 Si 0.945 O 4, on the basis of 4 oxygen atoms.The crystal structure has been studied by single-crystal X-ray diffraction.

Porous MgTi2O5/MgTiO3 composites with narrow pore-size ...

Chromium is steel-gray, lustrous, hard, metallic, and takes a high polish. Its compounds are toxic. It is found as chromite ore. Siberian red lead (crocoite, PrCrO 4) is a chromium ore prized as a red pigment for oil paints.. Emerald is a form of beryl (a beryllium aluminium silicate) which is green because of the inclusion of a little chromium into the beryl crytal lattice in place of some of ...

Chromite (compound) - Wikipedia

Abstract. The morphological manipulation and structural characterisation of TiO 2 –MgO binary system by an aqueous particulate sol–gel route were reported. Different crystal structures including pure MgTiO 3, mixtures of MgTiO 3 and TiO 2 and mixtures of MgTiO 3 and Mg 2 TiO 4 were tailored by controlling Mg:Ti molar ratio and annealing temperatures as the processing parameters.

Chromite - Wikipedia

Crystal chemistry and structural refinement of chromites from different chromitite layers and xenoliths of the Bushveld complex Locality: Bushveld complex, South Africa

WebElements Periodic Table » Chromium » the essentials

The Crystal Structure of Ilmenite. In accordance with the observed exter. which is controlled by five parameter values.nal symmetry (face development) of ilmenite it was found that crystals of this mineral are isomorphous with the space group C:i.

Crystal structure refinement of Co-doped lanthanum chromites

Fig. 11.1 shows crystal structures of chromite spinel (Sanchez-Segado et al., 2015). Large variations in the total and relative amounts of Cr and iron in the lattice occur depending on the different geological and geographical distribution of chromite deposits (Rao et al., 2010).

Shepherd 2015, Chromite Crystal Structure and Chemistry ...

E.g. MgAl 2 O 4 (known as spinel), Mn 3 O 4, ZnFe 2 O 4, FeCr 2 O 4 (chromite) etc. CRYSTAL STRUCTURE OF NORMAL SPINELS (AB 2 O 4) A spinel unit cell is made up of 8 FCC cells. The anions (usually oxide ions: O 2-) occupy the FCC lattice points.

Ilmenite | X Ray Crystallography | Crystallography

Chromite is the most important chromium ore mineral. It forms a complete solid solution series with many other members of the group, eg. in the Chromite-Hercynite Series, Chromite-Spinel Series, Chromite-Magnetite Series and the Chromite-Magnesiochromite Series.It is the iron analogue of Zincochromite, Cochromite, Manganochromite and Magnesiochromite and the Cr analogue of …

Chromite Crystal Structure and Chemistry applied as an ...

Chromite Crystal Structure and Chemistry Applied as an Exploration Tool (Thesis format: Integrated Article) by Patrick H.M. Shepherd Graduate Program in Earth Science A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science The School of Graduate and Postdoctoral Studies The University of Western Ontario

Chromite ore | CrFeO4 - PubChem

Chromite is an iron chromium oxide: FeCr 2 O 4. It is an oxide mineral belonging to the spinel group . Magnesium can substitute for iron in variable amounts as it forms a solid solution with magnesiochromite (MgCr 2 O 4 ); [5] substitution of aluminium occurs leading to hercynite (FeAl 2 O 4 ).

Chromite: Chromite mineral information and data. - Mindat.org

The 3D image shows the chromite rim and the central skeletal crystal structure forming a double Y shape. C, Atomic number contrast image of the nodular chromite containing a core skeletal crystal black box outlines the EBSD image in Fig. 8 .

Crystal structure refinement of Co-doped lanthanum ...

crystal structure, elongated MgTi 2O 5 grains were formed during the insitu processing. At 1000°C, equiaxed fine MgTiO 3 particles formed colony-like structure, and they dispersed in the elongated MgTi 2O 5 grains matrix(Fig. 3(a)). At 1100°C, MgTiO 3 grew with the size of ³1¯m, and they dispersed more

Chromite - Revolvy

Crystal structure of spinel In chemistry the term chromite has been used in two contexts. Under IUPAC naming conventions, chromate(III) is preferred to chromite .

dolomite | Formation, Structure, Properties, Uses, & Facts ...

Crystal structure of spinel In chemistry the term chromite has been used in two contexts. Under IUPAC naming conventions, chromate(III) is preferred to chromite. For compounds containing an oxyanion of chromium in oxidation state 3 For other compounds of chromium(III) as a means of distinguishing a chemical species such as hexacyanochromite(III).

AMCSD Search Results - rruff.geo.arizona.edu

Crystal structure refinement of Co-doped lanthanum chromites ... crystal structure data for the refinements of LaCrO ... S19 Powder Diffr. Suppl., Vol. 23, No. 2, June 2008 Crystal structure refinement of Co-doped lanthanum chromites S19. i.e., surfaces with the appearance of sponges. As a general remark, the observed shape was similar for ...

Spinel group - Wikipedia

entations effects on 18O while chromite does not? The crystal structures of chromite and magnetite are both hexoctahedral, face-centered cubic, with very similar unit cell lengths (a = 8.344Å and a = 8.397Å, respectively). The major difference between the two minerals is the magnetic properties of magnetite that are absent in chromite.

Tailoring of morphology and crystal structure of ...

The members of the spinel series often substitute for one another in the crystal structure, so that most specimens are mixtures. For general information on the use and occurrence of the chromium- and iron-spinel series, see chromite; magnetite.

CHEMISTRY AND MINERALOGY OF EARTH'S MANTLE High …

Crystal Structure: Mouse drag1 - LMB Manipulate Structure drag2 - RMB Resize/Rotate Keyboard S - Stereo Pair on/off H - Help Screen I - Data Info A - Atoms On/Off P - Polyhedra On/Off B - …

SPINEL STRUCTURE | EXPLANATION - adichemistry.com

High-pressure high-temperature transitions in MgCr 2O 4 and crystal structures of new Mg 2Cr 2O 5 and post-spinel MgCr 2O 4 phases with implications for ultrahigh-pressure ... chromite into Fe 2Cr 2O 5 + Cr 2O 3 at about 14 GPa and 1200 qC, prior to transitions to CF- or CT-phase at higher pressure (Eno-

University of Minnesota's Mineral Pages: Biotite

Their cleavage is a reflection of the minerals' crystal structure. This structure consists of aluminum silicate sheets that are weakly bound together by layers of positive ions. In phlogopite, these positive ions are primarily potassium and magnesium, while in biotite they are dominantly potassium and iron with only minor magnesium.

Spinel | mineral | Britannica.com

REFERENCES for Chromite; American Mineralogist Crystal Structure Database Record: [view record] Anthony J W, Bideaux R A, Bladh K W, and Nichols M C (1990) Handbook of Mineralogy, Mineral Data Publishing, Tucson Arizona, USA, by permission of the Mineralogical Society of America.