Composition and Origin of Ferromanganese Crusts from Equatorial Western Pacific Seamounts

In the equatorial western Pacific, iron-manganese oxyhydroxide crusts(Fe-Mn crusts) and nodules form on basaltic seamounts and on the top of drowned carbonate platform guyots that have been swept free of pelagic sediments. To date, the Fe-Mn crusts have been considered to be almost exclusively of abiotic origin. However, it has recently been suggested that these crusts may be a result of biomineralization. Although the Fe-Mn crust textures in the equatorial western Pacific are similar to those constructed by bacteria and algae, and biomarkers also document the existence of bacteria and algae dispersed within the Fe-Mn crusts, the precipitation, accumulation and distribution of elements, such as Fe, Mn, Ni and Co in Fe-Mn crusts are not controlled by microbial activity. Bacteria and algae are only physically incorporated into the crusts when dead plankton settle on the ocean floor and are trapped on the crust surface. Geochemical evidence suggests a hydrogenous origin of Fe-Mn crusts in the equatorial western Pacific, thus verifying a process for Fe-Mn crusts that involves the precipitation of colloidal phases from seawater followed by extensive scavenging of dissolved trace metals into the mineral phase during crust formation.

Characteristics and geological genesis of pyrites in coal of Huainan

Using optical microscope and scanning electron microscopy （SEM）, revealed the content of pyrite and the microscopic or sub-microscopic occurrence features of pyrite in coal of Huainan. The samples of this study are from four different mines in Huainan coal field. The results show that, in general, the coal of Huainan is low sulfur coal, but the con- tent of pyrite in Guqiao mine is relatively higher. The occurrence types of pyrite in coal mainly include： strawberry ball pyrites, massive pyrites, tuberculoid pyrite and pyrite filling in cracks or joints. After analysis based on three indicating facies parameters IAA, IS and/R, the reason for the higher level of pyrite component is that the deoxidization of swamp wa- ter is stronger, salinity is greater and the hydrodynamic is bad. The strawberry ball pyrites found in Guqiao mostly formed in the syngenesis stage. The spherical raspberry pyrites symbiotic with clay minerals was formed due to the reaction of H2S with Fe in the grid of silicate crystal.

Dysprosium Modification of Cobalt Ferrite Ionic Magnetic Fluids

Dysprosium composite cobalt ferrite ionic magnetic fluids were prepared by precipitation in the presence of Tri-sodium citrate. Influence of dysprosium modification on magnetic property is studied. The result shows that magnetic response toward exterior magnetic field can be improved by adding Dy3+. Studies also show that the increase of reaction temperature may improve the modification effect of dysprosium. By adding dysprosium ions, the average diameter of the magnetic nanoparticles will be decreased evidently. It is clear that the particles appear as balls. Cobalt ferrite with sizes of 12-15 nm, rare earth composite cobalt ferrite with sizes of 6-8 nm.

Synthesis and Structure of Paramagnetic β-OctamolybdateComplex, [Fe(2,2'bipy)_3]_2[Mo_8O_26]·6H_2O

A novel octamolybdate complex, [Fe(2,2?bipy)3]2[Mo8O26]6H2O has been synthesized via the hydrothermal technique, and it crystallizes in monoclinic, space group P21/c with two molecules in a unit cell: a = 1.21512(5), b = 1.36840(5), c = 2.18823(9) nm, b = 90.515(1), Mr = 2340.42, Z = 2, V = 3.6384(2) nm3, Dc = 2.136 g/cm3, F(000) = 2296, l(MoKa) = 0.071073 nm, = 1.813 mm-1, R = 0.0719 and wR = 0.1093 for 4058 observed reflections with I≥2s(I). The structure is characterized by the co-existence of octahedral [Fe(2,2?bipy)3]2+ cations and b-octamolybdate [Mo8O26]4- anions. The magnetic susceptibility data show a Curie-Weiss paramagnetic behavior (q = -5.201 K) in accordance with the spin-only ground state of FeⅡ ions. IR, UV-Vis, and EPR spectra are also briefly noted in this paper.

Preparation of water-soluble magnetic nanoparticles with controllable silica coating

This work provides a general method for preparing monodisperse, water-soluble and paramagnetic magnetic nanoparticles which are easy to be modified. Firstly, magnetic silica with core-shell structure was prepared according to a previous work. Then, the magnetic silica was treated with alkali solution to afford magnetic nanoparticles. With the increase of calcination temperature for the preparation of magnetic silica, the crystallinity and the magnetic responsibility of magnetic silica strengthened, meanwhile, the corresponding magnetic nanoparticles kept monodisperse without any aggregation. The magnetic nanoparticles are comprised of cobalt ferrite and a silica coating. The silica coating on the cobalt ferrite facilitates the magnetic nanoparticles well-dissolved and monodisperse in water, and easilv modified.

Preparation and ζ-potential characterization of highly dispersible phosphate—functionalized magnetite nanoparticles

By the combination of high-temperature organometallic synthesis and phase transfer through complete ligand-exchange withmixed phosphate, highly water-dispersible Fe3O4nanoparticles with narrow size distribution are obtained, which show appli-cable response to magnetic field. IR and -potential characterization of this system provides insights into ligand structures onparticle surface.

Theoretical studies on phosphoraniminato derivatives of Keggin-type polyoxometalates [PW_(11)O_(39){M^VNPPh_3}]^(3-)(M = Fe,Ru):Electronic structures and bonding features

Transition metal phosphoraniminato derivatives of Keggin-type polyoxometalates(POMs) are important intermediates in N-transfer reactions.Density functional theory(DFT) has been employed to calculate the electronic structures,bonding features and redox properties of the iron and ruthenium phosphoraniminato derivatives of Keggin-type POMs,[PW11O39{MVNPPh3}] 3-(M = Fe,Ru).Our DFT calculations show that both anions have the same qualitative M-N single bond features.However,the calculations predict that the FeN system possesses a lower energy and more accessible metalnitrogen antibonding orbital than the RuN system.This results in a greater weakening of the Fe-N bond in the reduction process,and thus enhances its N-transfer reactivity.