Iranian Journal of Crystallography and Mineralogy
Year:2012 | Volume:20 | Issue:1|Papers Count:20

The title compound (C10H9N2) [Cr (C6H7NO6) 2] (C10H8N2) 2H2O or (4, 4'-bipyH) [Cr (ntaH) 2] (4, 4'-bipy) ·2H2O (ntaH3 is nitrilotriacetic acid) was synthesized by reaction of Cr (NO3) 3. 9H2O with 4, 4'-bipyridine, and nitrilotriacetic acid with 4:2:1 molar ratio in aqueous solution. The crystal structure of this complex was identified using X-ray crystallography. The unit cell parameters are as follows: a=9.8501 (3) A, b=13.157 (2) A, c=26.842 (4) A, b=104.807 (7)o.The final R value is 0.041 for 7747 independent reflections. The title compound crystallized in monoclinic system and belongs to P 21/c space group. The central CrIII atom is coordinated by two tridentaid (ntaH2) ligands and the resulted CrO4N2 set can be described as distorted octahedral geometry. The asymmetric unit contains two half of anionic complex, one 4, 4'-bipyridiniom ion, (4, 4'-bipyH)+, one neutral 4, 4'-bipyridine molecule and two non-coordinated water molecules. Intramolecular hydrogen bonds,p-p [centroid –centroid distances of 3.674 A], C-H…p, O-H…p and N-H…p stacking interactions [with distance of 3.714, 3.736 and 3.270 A respectively], connect the various components into a supramolecular structures.

Toye-Darvar granitoidic pluton is located in southwest of Damghan, in the southern flanke of eastern Alborz structural zone. Despite of its uniform appearance in the field, this pluton is composed of a rock with a wide range of composition including of diorite, monzodiorite, monzonite, quartzmonzonite and granodiorite with monzonite-quartzmonzonite prevalence. Based on the field observations, this pluton intruded in the Bayandor, Soltaniyeh, Zagoon and Laloon formations with the Late Precambrian-Cambrian age and not found in Jirood Formation, in opposite of pervious reports, then its age isn't Late Devonian. Absence of contact metamorphism indicates the fluid deficence and relatively dry nature of magma, smal size of pluton and diapiric ascent of the magma in a cold solid state in shallow depths of the crust. Existence of Fe-Mn oxide-hydroxides, fluorite, barite, zinc and lead viens in the country rocks, prevalence of hypersolvous-subsolvous reaction fine grain granular textures (perthitic, myrmekitic, graphic and granophyric), alkaline nature of magma, LILE and incompatible elements enrichment, high contents of HFSE in comparision to the other granitoids, low CaO and MgO contents, high FeOt/MgO ratio (prevalence of iron rich mineralogy), high Ga/Al ratio and plotting the samples in the A-type granitoid fields in geochemical discriminat diagrams, all suggest that this pluton is A1 sub-type granitoids (related to intraplate rifting magmatism). Different evidences indicate a close relationships between Toye-Darvar granitoidic pluton and Lower Paleozoic rifting magmatism (Ordovician-Silurian time) in the Gondwanian uniform platform of Iran in relation to initiation of the opening of the paleotethys ocean that reported from different localities in Iran, particularly in Alborz and Central Iran, and the other adjacent countries.

Gara-aghaj deposit located 36km northwest of urumieh is one of the titanium phosphorous resources in Iran. The previous exploration studies indicated that there is 102Mt phosphorous ore deposit with average grading of 2.3% P2O5. In this research, the mineralogical studies of collected representative samples were performed by XRD, XRF, optical microscopy and SEM equipped by EDX. These studies indicated that ilmenite, magnetite and apatite are the main valuable minerals. The gangue minerals consist of the silicate minerals such as pyroxene, olivine, plagioclase and some secondary minerals. Analysis of apatite by EDX showed the presence of fluor-apatite in the ore. From textural viewpoint, apatites is mainly interlocked with ilmenite, magnetite and some gangue minerals with 60 microns liberation degree but there are some inclusions of apatite inside ilmenite and magnetite. The heavy liquid separation tests indicated that the first type of apatites, with density of 3, is mainly concentrated in tailing of gravity separation methods. This type of apatites is recoverable by flotation method. So, apatite concentrate can be obtained as a by-product of ilmenite concentration process by gravity methods.

Hydroxy davyne is a hydrated aluminosilicates with the same structure as cancrinite mineral group. Scientist categorized hydroxy davyne as zeolite because of its low temperature formation conditions and hydrated structure. Existence of [Ca.Cl]+group instead of [Na.H2O]+ group is the significant property of this mineral. Alteration of volcanic ash in presence of alkaline hydrothermal solutions is a common procedure to originate zeolite minerals. Therefore the aim of this research is to estimate of hydroxy davyne formation through phase transition of volcanic ash in the presence of alkaline solutions at hydrothermal conditions. The results of this research show that hydroxy davyne originate at 150oC in the presence of alkaline hydrothermal solutions with high concentration of Na+, K+and Cl-.

The amphibolitic xenoliths are the most aboundant xenoliths in the Markouh dacitic dome northeast of Birjand. The Markouh dacite is composed of plagioclase, quartz, green hornblende, biotite, magnetite and amphibolitic xenoliths that are contaning brown- green hornblende, plagioclase±biotite±quartz±pyroxene. Determination of temperature and pressure of these rocks, based on Al content in amphibole, indicate that green hornblende of host rock are formed in 784-804oC temperature and 5-6 Kbar pressure equivalent to 20.44-23.52 Km depths and xenoliths are formed in 777-845oC temperature and 5-7.5 Kbar pressure equivalent to 20-30 Km depths. The more extensive P-T domains for amphibolitic xenoliths to host rocks show that they are formed at first stage during a regional metamorphism from ophiolitic basement in the amphibolite facies. Then with increasing of P-T in the late amphibolite and early granulite facies, green hornblende changed to brown hornblende plagioclase riching in Ca and clinopyroxene is formed. At last, the pyroxene amphibolites falling into magma where condition was suitable for the formation of green hornblende and occured at retrograde contact metamorphism. Thus brown hornblende is changed to green hornblende again. The results of microprobe analysis and microscopic evidence confirmed this matter. The plagioclases in xenoliths are the more rich in Ca to compare with the host rock.

Halakabad is located about 30 km south of Sabzevar. Basalt, andesite, hornblende andesite and hornblende dacite are the oldest volcanic rocks cropping out in the study area. Monzodiorite, quartz diorite, quartz monzodiorite, quartz monzonite, and hornblende quartz monzodiorite intruded the volcanic rocks. Application of component analysis is one of the methods that can help to reveal simpler patterns within a complex set of variables. In mineral exploration, the most common application of this multivariate analysis method is to characterize and map interrelationship within high volume surface geochemical data sets. Application of component analysis in Halakabad shows that the most variable can be categorized in five components. Results for geochemical data show first component has positive loading for Cu, Zn, Co, V as well as Li, Th, Cs, Sr and negative loading for Pb, Ba, Rb and Nb. Second component has negative loading for Rb, Sr, Th, Ba and positive loading for other elements. Association of Zn with Pb and F demonstrates another mineral para genesis in the area. Third component has positive loadings for Ni, Co, Cr and Zn. The chemical elements with positive loadings of the second component are associated with alteration and sub volcanic rocks. Principal component analysis in Halakabad area demonstrated at least two type of Cu and Zn mineralization.

The Emarat and Muchan zinc-lead ore deposits are located in southwest of Arak within the middle part of the Malayer-Esfahan belt. These deposits have formed as stratabound within carbonate strata of Lower Cretaceous. Mineralization in these deposits is mainly open space filling, which consists of sphalerite, galena, pyrite and minor quantities of chalcopyrite associated with host rock silicification. The most abundant sulfide mineral is sphalerite, which occurs in two generations. Galena as an accessory mineral has been formed during and after formation of sphalerite. Based on textural evidence, silicification occurs in two separate stages. First, microcrystalline quartz replaces nearly all the original carbonate host rock. During the second stage, the vugs and fissures of the silicifed host rock were filled with macrocrystalline quartz associated with mineralization. The sulfur isotopic data indicated the d34S values of sulfide minerals varies from +4.8 to +11.8 per mil. Based on these results, the Lower Cretaceous seawater acted most likely as the source of sulfide mineralization. The isotopic temperatures from two sphalerite-galena pairs at Emarat deposit varied from 121.1oC in stage I to 112.8oC in stage II, which are lower than the isotopic temperature of the Muchan deposit (134.3oC). Combination of geological, mineralogical and sulfur isotope results suggest that connate water, metals and silica have been derived from diagenesis of Jurassic shales and sandstones. Furthermore, thermochemical sulfate reduction, interaction of the ore fluids with the host rock, and cooling were proposed to be the main ore depositional mechanisms.

Reflectance spectrometry techniques with the integration of remote sensing data help us in identifying and mapping the phenomena on the earth. Using these techniques to discriminate the petrologic units independently and without knowing the spectral behavior of rocks along the electromagnetic wavelengths can not be so much useful. For the purposes of this study, 65 samples of igneous and metamorphic rocks from Hamedan region were collected and their spectra were measured using Fieldspec3 device in laboratory. The spectra were analyzed on the basis of absorption, position and shape. Petrographic analyses were used to interpret the absorption patterns as well. Then the spectra were classified according to spectral patterns. This measurement was done on both freshly cut and exposed surfaces of the samples and except a few samples, the two sets of spectra did not differ significantly. Finally, to evaluate the possibility of recognition of these targets, the responses of two hyperspectral and multispectral sensors were simulated from spectra representative of the spectral classes, showing that significant identification and classification of well exposed rocks are potentially possible using remote instruments providing high quality spectra. Also Aster simulation showed that a preliminary gross discrimination of rocks was however possible.

Three types of serpentine polymorphs (lizardite, chrysotile and antigorite) are found in serpentinites from the Baft ophiolite melange which are different in the textural features and chemical compositions. Lizardite is seen as layered structures that set in the matrix of peridotites, while antigorite is formed in veins or sheared zones as blade crystals and chrysotile develops as shiny and golden fibers in small cracks. The studied peridotites, based on degree of serpentinization, can be divided into three subdivisions including relatively serpentinized peridotites (up to 50 vol.% serpentinization), mainly serpentinized peridotites (50-90 vol.% serpentinization) and completely serpentinized peridotites (90-100 vol.% serpentinization). We suggested three models for serpentinization of olivine in this area. First model contains serpentinization of olivine grain boundaries with unaltered centers. The process has developed in relatively serpentinized peridotites. Second model includes redeveloping serpentinization of inherited olivine grains from the first model and third model contains complete serpentinization of olivine grains. Second and third models have been developed in mainly and completely serpentinized peridotites. It seems that involved lizardite and chrysotile are the result of static alteration in an ocean floor like environment, while interpenetrative-blade antigorites have been produced by dynamic metamorphism. Production of antigorite can be related to subduction of Nain-Baft oceanic crust or it can be related to obduction of serpentinized pridotites in other times, it is possible that lizardite and chrysotile have formed before closure of Nain-Baft Small Ocean.

Kalchoyeh copper deposit is located about 110 km east of Isfahan, in Central Iran, Urumieh-Bazman volcano plutonic belt. Host rocks of this deposit are Eocene volcanic rocks and tuffs which are pyroxene andesitic lava and sandy and lithic tuffs. Sandy tuffs are the main host rocks of the deposit. Ore mineralization is taken place as veins and veinlets and quartz is the main gangue mineral. Hypogene mineralization includes chalchopyrite, galena and magnetite. Covellite and chalcocite are also found as supergene mineralization.Micro thermometric measurements of fluid inclusions in quartz indicate homogenization temperatures between 101 to 312oC and salinities from 0.7 to 7.3 wt % NaCl equivalent. Boiling occurred in the mineralizing fluids at 400 meter below the paleo- water table. Based on performed studies, Ore fluid was low to medium temperature and low salinity and potential mineralization. In addition ore mineralization in Kalchoye is type of epithermal deposits with low sulfidation.

Soltan Abad metamorphic complex cropped out at NE of the Sabzevar ophiolites. There are extensive exposures of bluschist facies rocks inside a serpentinitic groundmass as tectonic melange in this metamorphic complex. Field investigations, petrography and thermo barometry indicate that these rocks have experienced two metamorphic phases. Paragenesis of the first metamorphic phase consists of oriented Na-amphibole, epidote and phengite and the first generation of garnets that have formed during burial and subduction. Pressure and temperature conditions of the first metamorphic phase have been 11 to 14 Kb and 350 to 420oC respectively. The second metamorphic phase, due to injection of trondhjemitic plutons, resulted in crystallization of coarse porphyroblasts of albite, second generations of garnet and epidote as well as crystallization of Ca-Na amphiboles around Na-amphiboles. Metamorphic conditions of this stage have obtained as P=4-7 Kb and T=500-580oC. It seems that the collision of Arabian plate with Central Iranian microcontinent and movment of this microcontinet toward the north east, led to subduction of Sabzevar oceanic basin and partial melting and generation of trondhjemite during Middle Paleocene. As a consequence of intrusion, bluschists of the accretionary prisms have undergone retrograde metamorphism.

The (Early Carboniferous) Shishtu 2 Formation at the study area is composed of a shallowing upward sequence. Skeletal packstones consist of crinoids, brachiopods, bryozoans, trilobites, corals and rare foraminiferas. The carbonates of this formation have undergone a complex diagenetic history and the most diagenetic events are silicification and pyritization. The complexity of silicification in these limestones is further demonstrated due to selectivity of silicification of different faunas. Based on morphology, four fabric types are distinguished in silica including microcrystalline quartz, spherulitic chalcedony and slightly mega quartz and euhedral quartz. The observed correlation between skeletal fragments and quartz replacement types (QRT) shows that skeleton microstructure may control QRT. The silicification of the skeletal grains in this study occurred along thin solution films where skeletal calcite dissolved and silica precipitated. The brachiopods, corals and crinoids are the most susceptible organisms to silicification. The presence of impurity of Mg2+ in the composition of skeletal grains (e.g., brachiopods and crinoids) may be the controlling factor for their susceptibility for silicification. Diagenetic pyrite in the limestone of the Carboniferous in this area exhibit as euhedral pyrite which occurs as singular euhedral crystals. These may occur after the death of faunas and during burial diagenesis. This process is strongly dependent on the redox potential (dysaerobia to anaerobia) and availability of the required elemental ingredients (Fe and S) in the burial realm.

The studied gabbroic rocks have exposures around Darreh-Bid salt dome. The rocks are located about 130 km south of Shahrekord (Chaharmahal and Bakhtiari Province). The studied area is a part of Zagros structural zone. Mineral chemistry studies were done on clinopyroxenes in the gabbroic rocks of the Darreh- Bid salt dome. The clinopyroxenes are diopsid and augite and are plotted in low pressure field. The clinopyroxenes have been crystallized from magma with almost 10% H2O. Pressure estimates from the clinopyroxenes in the range of<5kbar. The magma has been rich in Ti and has MORB nature. Fe3+- values of the clinopyroxenes reveal high oxygen fugacity. The clinopyroxene composition yields the crystallization temperatures that range from 650-800oC.

Conductive transparent ZnS/M/ZnS, (M=Au, Ag, Cu, Al) nano-structures have been simulated by optimization layers thickness, and gold, silver, copper, and aluminum materials were used as a metal layer and zinc sulfide for dielectric layers. Then the optimum simulated structure has been fabricated on a glass substrate by thermal evaporation. The crystallinity properties of the structures, such as grain size and lattice parameters, have been calculated from XRD pattern. The optical transmittance and absorption spectra show that the structures are absorber of the ultraviolet and infrared and transparent against visible lights. These results were confirmed by calculated figure of merit and luminous transmittance and measuring the rate of heat dissipation.

In this research magnetic nanoparticles of cobalt–zinc ferrite (Co1-xZnxFe2O4, x=0, 0.2, 0.4, 0.6, 0.8), have been synthesized by the coprecipitation method, using stable ferric, zinc and cobalt salts with sodium hydroxide, at 80oC. Phase formation and the morphology of the resulting nanoparticles were studied by X-ray diffraction and transmission electron microscopy respectively. Mean crystallite size of the nanoparticles was calculated using Scherrer's formula and the results show that the mean crystallite size decreased from 13 to 8 nm by increasing x values from 0 to 0.8. The super paramagnetic behavior and dependence of blocking temperature TB on frequency were studied, using AC-susceptibility measurements at the range of 300 Hz to 100 kHz and fitted by Vogel-Fulcher law. According to this law, it was found that there is a strong magnetic interaction between the ferrite nanoparticles.

In this paper, Au nanoparticles are synthesized by solution method. The effect of these nanoparticles on the Bi1.6Pb0.4Sr2Ca2Cu3Oysuperconductor properties has been investigated. The critical current density, activation energy and room temperature resistivity were measured by the standard four-probe method. The microstructure and morphology of samples have been studied by X-ray diffraction, Scanning Electron Microscope and Energy Dispersive X-ray. The results of X-ray diffraction patterns show that the low amount of Au and annealing time of 72h enhance the fraction of Bi -2223 phase. Also crystallography studies showed that the gold has entered the superconductor's structure and the results were in consistency with superconductor's SEM images.