Synthesis, Crystal Structure and Magnetic Property of Disodium Biscarbonato cobaltate(Ⅱ) Tetrahydrate, Na_2Co(CO_3)_2·4H_2O

The title compound, Na 2Co(CO 3) 2·4H 2O, was synthesized by dropwise addition of 1.0 mL of 1 mol/L Co(CH 3COO) 2 to 50 mL of aqueous solution containing 7.0 g(66.0 mmol) of Na 2CO 3 and 2.5 g(29.8 mmol) of NaHCO 3 under stirring. A rose colored rhombohedral crystal grew by the slow evaporation of the solution of the title compoud at room temperature. The crystal structure was established on the basis of the single crystal X ray diffraction data. Na 2Co(CO 3) 2·4H 2O crystallizes in the monoclinic space group C2/c with a =0.856 6(1) nm, b =0.714 6(1) nm, c = 1 438 7(2) nm, β =97.59(1)° , V =0.873 0(2) nm 3 , D x=2.260 g/cm 3, F (000)=596, M r=296 99, μ (Mo K α)=21.06 cm -1 , Z =4 and the final R(F) =0.032 and wR(F 2) =0.068 on the basis of 947 reflections ( F 2 ≥ 2σ(F 0 2)). The crystal consists of H 2O molecules, Na + ions and 2D 2 ∞[Co(CO 3) 2] 2- layers extending parallel to (001). H 2O molecules and Na + cations are located between the 2D layers. Each Co atom is tetrahedrally coordinated by four O atoms from four CO 2- 3 groups with d (Co\_O)=0.206 5(2) nm, 0.207 6(2) nm and the angle of O\_Co\_O is in the range of 97.7(1)°—128.5(1)°. The CO 2- 3 group bridging two Co atoms via two O atoms deviates from D 3h symmetry with d (C\_O)=0.127 2(3)\_0.129 9(3) nm and the angle of O\_C\_O is in the range of 119.5(2)°\_123.4(2)°. Each Na atom, with two close Na neighbours at 0.338 4(2) nm and 0 346 7(2) nm, respectively, is octahedrally coordinated by six O atoms from four H 2O molecules and two carbonate groups belonging to two layers with d (Na\_O)=0.232 7(2)\_0.241 1(2) nm. Of two crystallographically different H 2O molecules, one forms hydrogen bonds to two CO 3 2- groups of one 2D layer, and the other to those from two different 2D layers. Na 2Co(CO 3) 2·4H 2O is antiferromagnetic below 16 K, and between 30\_300 K its magnetic behaviour obeys Curie Weiss law χ m(cm 3·mol -1 )=2.625/( T -12.1) with μ eff =4.5 B.M. at 298 K.

Structural Transition and Magnetic Property of Bi1-xYbxFeO3

Bi1-xYbxFeO3（0〈x〈0.2） powders have been synthesized using a sol-gel method. The X- ray diffraction data show a structural transition from the rhombohedral R3c phase to the orthorhombic Pnma phase between x=0.1 and 0.125, which should induce a ferroelectric- paraelectric transformation. The phase transition is also proven by the Raman spectroscopy. A moderate signal on magnetization appears to illustrate the enhancement of magnetization at the transformation boundary, which is suggested to be the destruction of the spin cycloid structure at low concentration. The appearance of antiferromagnetic ordering is proposed to account for the afterward reduction of the magnetization at high concentration.

Crystal Structure and Magnetic Property of 2-（Imidazo[1,2-α]pyri-din-2-yl）- 2-oxoacetic Acid and Its Perchlorate

We herein report two crystals based on 2-（imidazo[1,2-a]pyridin-2-yl）-2-oxoacetic acid rad- ical and its perchlorate, and investigate the relationship between magnetic properties and crystal stacking structures or supramolecular interactions. 2-（imidazo[1,2-a]pyridin-2-yl）- 2-oxoaeetic acid radical in two crystals mainly exist as diamagnetic dimer formed via short atomic contacts or supramolecular interactions （hydrogen bonds, anion-Tr or lone- pair-~r interactions）, leading to low magnetic susceptibilities. 2-（imidazo[1,2-a]pyridin-2-yl）- 2-oxoaeetic acid radical crystal exhibits quasi-one-dimensional columnar stacking chain and weak antiferromagnetism. However, its perchlorate crystal possesses one-dimensional double- stranded chain structure assembled through double hydrogen bonds and anion-To interactions, and reveals weak ferromagnetism.

Magnetic property and recording performance of chemical deposition CoP thin films

The thickness of CoP thin films prepared by wet chemical deposition is of crucial importance on magnetic property and recording perform-ance. The coercivity of CoP films decreased with increasing film thickness. The coercivity was 45.37 kA m 1 at the thickness of 300 nm, and decreased to 21.65 kA m 1 at 5.7 μm. Recording performance tests indicate that, for drums with the same size, different recorded magnetic pole density have different thickness requirements. For 40 mm diameter magnetic drum, the optimal CoP thickness is 3～10 μm for 256 re-corded magnetic poles, 1～2 μm for 512 recorded magnetic poles, and 500～800 nm for 1024 recorded magnetic poles.

Magnetic property of loess strata recorded by Kansu profile in Tianshan Mountains

Kansu （KS） profile is located in the east of Yili basin, western Xinjiang, where typical loess sediments are distributed. The magnetic parameters （such as IRM, SIRM SOFT, and M） and grain size in the KS profile were analyzed in the study. The results showed that the magnetic property of KS loess is dominated by ferrimagnetic minerals, such as magnetite and maghemite. Antiferromagnetic and superparamagnetic minerals also exist in the profile, but had less impact on magnetic susceptibility. Compared with the typical loess sediments of the central Loess Plateau in China, the strata of Kansu profile contained more magnetic minerals and hard magnetic minerals. The analysis of grain size for magnetic minerals indicated that the properties of loess and paleosol were respectively dominated by PSD/MD and coarse SSD magnetite. The research found that the contents of magnetic minerals in loess and paleosol sequences in Kansu profile were similar, but the proportion of fine grained magnetite and soft magnetic minerals were varying, which implies a positive relationship between the value of magnetic susceptibility and intensity of pedogenesis.

Synthesis,Crystal Structure,Thermal Stability,Luminescence and Magnetic Property of a New Mn^Ⅱ Coordination Polymer

One new coordination polymer, [Mn(Hbtc)(bpy)(HO)]1, was synthesized by the reaction of manganese(Ⅱ) salt under pH-controlled hydrothermal conditions with unsymmetrical polycarboxylic acid of 1,2,4-benzenetricarboxylic acid(Hbtc) and 2,2?-bipyridine(bpy). The structure of complex 1 was characterized by single-crystal X-ray diffraction, IR spectra, powder X-ray analysis, thermal gravimetric analysis(TGA), UV-Vis spectrometry, photoluminescence and magnetic susceptibility. Complex 1 is a one-dimensional(1D) polymeric single-chain structure. Photoluminescence property is quite similar to the bpy ligand. Magnetic susceptibility measurement indicates that 1 shows a weak ferromagnetic coupling between the Mn~Ⅱ ions.

Three-Dimensional Normal Stress for Controlling Electronic Structure and Magnetic Property of Fe2Ge

A system study of the three-dimensional normal stress for regulating electronic structure and magnetic property of Fe_2Ge is studied. The density states of Fe more than 92% contribution come from Fe 3d,the density states of Ge mainly contributed from Ge 4p and Ge 4s,and the Fe 3d spin induces the Ge 4p electron transfer. The inductive effect increases germanium electron energy,weakens the Fe spin density of states,opposes the stability of the ferromagnetic state. The magnetic moment varies from 5 to 3 μB with the stress charges from-30 to 30 GPa. The charge of Fe is negative whereas the Ge atom is positively charged,the Fe atom loses charge,the charge transfers to the Ge atom. The unevenly distributed charge forms the newoccupy state and spin polarization state in the Fe_2Ge electron structure system. The Fe is the electron donor,the total electron is transferred to Ge,but the total numbers of gain electron and total numbers of lost electron are not equal,so the Fe_2Ge electron system may have hybridization between the Fe 3d state and Ge 4p state.The magnetic of Fe_2Ge mainly comes from the unoccupied Fe 3d orbital,the Fe 3d is positive spinpolarization state and the spin-polarization strength is decreased,the Ge 4p is negative spin-polarization state and the spin-polarization strength are increased. M oreover,electrons-spin polarization is relevant to the structure parameters of the Fe_2Ge system,and controls spin-polarized electronic behavior by means of adjusting ferromagnetic.

A One-dimensional Cobalt Coordination Polymer Based on Biphenyl-2,3,3',5'-tetracarboxylic Acid and N-donor Ancillary Ligands: Crystal Structure and Magnetic Property

Hydrothermal reactions of biphenyl-2,3,3A,5A-tetracarboxylic acid（H4bptc） with cobalt salt in the presence of 1,4-bis（2-pyridylmethyl）piperazin（bpmp） afforded one novel coordination polymer, namely, [Co（H2bptc）（bpmp）0.5（H2O）]n（1）. Its structure was established by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra and TG analysis. Complex 1 crystallizes in monoclinic, space group P21/c with a = 11.4839（11）, b = 16.6690（16）, c = 11.5559（11） A, V = 2201.8（4） A3, Mr = 539.35, Dc = 1.627 g/cm^3, μ（MoK α） = 0.841 mm-1, F（000） = 1108, Z = 4, the final R = 0.0309 and w R = 0.0705 for 4090 observed reflections（I 2σ（I））. Complex 1 displays a one-dimensional（1D） chain bridged by bpmp. Two carboxylic groups of H4 bptc ligand adopt μ01-η1：η1 and μ1-η1：η coordination modes to bridge adjacent Co（Ⅱ） ions together with bpmp ligand to give alternately arranged left- and right-handed helical chains. In addition, variable-temperature magnetic susceptibility measurements indicate that complex 1 shows weak antiferromagnetic interactions between the adjacent Co（Ⅱ） ions.

Hydrothermal Synthesis,Crystal Structure and Magnetic Property of a New Co(Ⅱ) Complex:[Co(4,4'-bpy)_2(H_2O)_2(4-FBA)_2]·(4,4'-bpy)

A new complex [Co（4,4＇-bpy）2（H2O）2（4-FBA）2]·（4,4＇-bpy）（1） has been hydro-thermally synthesized using cobalt,4,4＇-bipyridyl（4,4＇-bpy） and 4-fluorobenzoic acid（4-HFBA）,and characterized by thermal analysis,single-crystal X-ray diffraction and magnetic property.The complex crystallizes in the triclinic system,space group P,Z = 1.Crystal data：C54H44CoF2N8O6,Mr = 997.90,a = 9.134（2）,b = 11.555（2）,c = 12.867（3） ,α = 66.02（3）,β = 77.96（3）,= 73.11（3）°,V = 1180.9（4） 3,Dc = 1.403 g/cm3,μ（MoKα） = 0.433 mm-1,F（000） = 517,the final R = 0.0633 and wR = 0.1171 for 2152 observed reflections（I 〉 2σ（I））.The title complex is assembled into 1D supramolecular chains parallel to [001] based on the adjacent molecular ··· stacking interactions and hydrogen bonds.The variable temperature magnetic measurements show a weak ferromagnetic behavior over 300-160 K followed by antiferromagnetic behavior below 160 K for the title complex.

A New Mn(Ⅱ) Coordination Polymer: Synthesis, Structure and Magnetic Property

A new 2D compound,{[Mn6 L3(H2O)8]·0.69(C3 H7 NO)·3.31H2O}n(1,H4 L=1,1’-(1,4-phenylenebis(methylene))bis-(1H-pyrazole-3,5-dicarboxylic acid)),was synthesized and characterized by IR,TGA and X-ray single-crystal/powder diffraction.Compound 1 crystallizes in monoclinic system,space group C2/c with a=26.468(5),b=19.750(4),c=13.660(3)A,β=92.73(3)°,V=7132(2)A^3,Z=4,Mr=1824.12,Dc=1.699 g/cm3,F(000)=3705,R=0.042 and w R=0.117 for 8965 observed reflections(I>2σ(I)).In compound 1,all of the Mn(II)atoms are six-coordinated and take the octahedral geometry of[MnNO5].The 2D compound consists of secondary building unit[Mn3(μ2-O)(R-COO)3](SBU),in which two of the Mn^2+ions exhibit the same coordinated environments while another Mn^2+ion has a different one.The SBUs further connect with each other to form a 1 D inorganic chain which is connected with L^4-ligands to construct a 2D layer.Finally,strong O–H···O hydrogen bonds among the rich carboxyl molecules and O atoms from free DMF and guest water molecules connect the two-dimensional coordination network into a three-dimensional framework.Variable temperature magnetic measurements indicate the antiferromagnetic behavior in the Mn3 core in compound 1.

Rock magnetic property of gravity core CSH1 from the northern Okinawa Trough and the effect of early diagenesis

Detailed rock magnetic investigations were undertaken at 2 -4 cm interval for the gravity core CSHI （with a length of 17.36 m） from the northern Okinawa Trough. Time-scale of the core was constructed by two characteristic tephras and foraminferal assemblages, indicating an age of 50 ka for the bottom of the core. Except for three tephras and abrupt decrease in surface, there are little changes in all kinds of rock magnetic parameters that can be correlated to the climate change for the last 50 ka. Different from the common sediments, most S-ratios （S equals the negative ratio of IRM-0.3T to SIRM, which is an indicator of low coercivity content） of the sediments are smaller than 0. 9, which implies a substantial amount of magnetic minerals with high coercivity. The existence of iron sulphide （ greigite or pyrrhotite） is revealed by representative susceptibility - temperature curves showing 200 350 ℃ Curie temperature in addition to 580 ℃ of magnetite, and also by awful smell during heating and dark heating products. Both the occurrence of authigenic iron sulphide and quick decrease of magnetic parameters near the surface clearly show that sediments from Core CSHI have undergone early diagenesis. The featureless magnetic changes of the whole core except for three tephras mean that the post-depositonal alteration is so strong that most original signals have been destroyed. For the same reason, the organic matter in sediment and sulphate in pore water must have been consumed along with dissolution, precipitation of iron and manganese happening sequencially during the redox reaction series. Great caution must be taken when using these altered chemical parameters for the interpretation of climatic changes.

Hydrothermal Synthesis, Crystal Structure and Magnetic Property of a Novel Mixed Valence Decatungstate: [Cu(2,2′-bipy)_2]_2Na_2W_6~VW4^(VI)O_(30)·2H_2O

A novel Cu（II）-2,2＇-bipy-supported （bipy = bipyridine） mixed valence decatungstate, [Cu（2,2＇-bipy）2]2Na2W6^VW4^VIO30·2H2O 1, has been synthesized and structurally characterized by X-ray analysis. The crystal of 1 is of triclinic, space group P1^- with a= 10.9393（10）, b = 12.0492（2）, c = 12.3783（2）A, a = 80.631（10）, β= 70.226（10）, γ= 72.329（9）^o, V = 1459.64（4）A^3, Z = 1, Dc = 3.582 g/cm^3, F（000） = 1404, R = 0.0553 and wR = 0.1242 for 4607 observed reflections （I 〉 2σ（I））. The EPR spectrum of 1 indicates that its unpaired electrons are placed in the dx2-y2 orbital of the ground state of Cun. Furthermore, compound 1 shows an antiferromagnetic interaction.

Crystal Structure and Magnetic Property of a Two-dimensional Manganese Compound [Mn(PhCOO)_2(4,4'-bipyridine)]_n

A new two-dimensional polymeric manganese compound [Mn（PhCOO）2（4,4＇-bipyridine）]n 1 has been prepared and structurally characterized by X-ray diffraction. The complex crystallizes in space group Pbcn with a = 18.7158（2）, b = 11.6919（3）, c = 9.4799（2）A, V = 2074.42（7）A^3, Z = 4, Mr = 453.34, Dc = 1.452 g/cm^3, μ = 0.670 mm^-1 and F（000） = 932. The final refinement gave R = 0.0458 and wR = 0.1439 for 1358 observed reflections with Ⅰ〉 2σ（Ⅰ）. The complex consists of repeating units of Mn（PhCOO）2（4,4＇-bipyridine）. Each Mn center is sixcoordinated by four carboxylate O atoms of four benzoate anions and two pyridyl N atoms from bipy ligands to furnish a slightly distorted octahedral geometry. The two adjacent Mn atoms are connected by a pair of μ1,3-carboxylate groups to form infinite chains, which are further interlinked by bipy to complete a 2D grid network. The magnetic property of the polymeric complex has also been investigated.

Synthesis,Crystal Structure,and Magnetic Property of One 3D Nickel Coordination Polymer Based on 2-Hydroxy-5-(3',5'-terephthalic acid)Pyridine and 1,4-Bis(1-imdazoly)benzene

One novel nickel coordination polymer, {[Ni（OTP）（bib）1.5（H2O）]·2H2O}n（1, H2 OTP = 2-hydroxy-5-（3＇,5＇-terephthalic acid） pyridine, bib = 1,4-bis（1-imdazoly）benzene）, has been synthesized and characterized by elemental analysis（EA）, IR, powder X-ray diffraction（PXRD）, and thermogravimetric（TG） analyses. The crystal of 1 crystallizes in monoclinic, space group P21/n with a = 12.2860（5）, b = 13.8246（6）, c = 19.0140（8） A, β = 104.3870（1）°, V = 3128.2（2） A3, Z = 4, C32H28N7 Ni O8, Mr = 697.32, Dc = 1.481 g/cm^3, F（000） = 1444 and μ（Mo Kα） = 0.684 mm-1. The final R = 0.0704 and w R = 0.1764 for 5485 observed reflections with I 2σ（I） and R = 0.1087 and wR = 0.2010 for all data. Topology analysis reveals that complex 1 is a 3D 2-fold interpenetrated {4^4·6^6}-nov net based on the 1D [Ni（OTP）]n chain and the 2D [Ni2（bib）3]n sql sheet. And the variable-temperature magnetic susceptibility measurements exhibit weak antiferromagnetic coupling interaction.

Morphology, Size-controlled Synthesis of CoO Nanostructure and Its Magnetic Property

CoO nanostructures with tunable morphology and size have been prepared via a simple one-pot solvothermal synthesis. The as-prepared nanoparticles were fully characterized using X-ray diffraction（XRD）, transmission electron microscopy（TEM）, field-emission scanning electron microscope（FESEM）, etc. The morphology and size of the product can be easily controlled by adjusting the raw materials added. Reaction time and the solvent ratio also play important roles in the synthesis of octahedral nanostructures. The magnetic property of the as-prepared samples was also investigated.

A Carboxylate-bridged Co(Ⅱ) Layer Complex： Synthesis, Structure and Magnetic Property

A 2D coordination polymer, [Co（NPA）（H_2 O）_2]_n（1, H_2 NPA = 3-nitrophthalic acid）, has been synthesized by solvothermal method and characterized by single-crystal X-ray diffraction analysis, FT-IR spectroscopy, elemental analysis, thermogravimetric analysis and powder X-ray diffraction. Complex 1 crystallizes in orthorhombic space group Pbca with a = 7.2261（2）, b = 14.6450（5）, c = 19.6671（7） ？, V = 2081.31（11） ？~3, Z = 8, C_8 H_7 CoNO_8, M_r = 304.08, D_c = 1.941 mg/m^3, μ = 1.686 mm^（-1）, S = 1.054, F（000） = 1224, the final R = 0.0248 and wR = 0.0603 for 1834 observed reflections（I 〉 2σ（I））. The crystal structural analysis demonstrates that the Co（Ⅱ） ions in 1 are linked by single and double μ_2-1,3-bridging carboxylate bridges, forming a 2D layer structure. Moreover, magnetic property of 1 was also discussed.

A New Copper Coordination Polymer with Magnetic Property Based on 3-(1,2,4-Triazol-1-yl)benzoic Acid

A copper coordination polymer, namely [CuL2（H2O）2]·H2O 1（HL = 3-（1,2,4-triazol-1-yl）benzoic acid） has been synthesized by the hydrothermal reaction under 140 ℃. The structure of 1 was characterized by single-crystal X-ray diffraction analysis, elemental analyses, powder X-ray diffraction, IR spectroscopy, and thermogravimetric analysis. Single-crystal X-ray diffraction analysis reveals that 1 crystallizes in P21/n space group with a = 12.374（5）, b = 12.730（5）, c = 12.561（5） A°, β = 91.105（9）o, V = 1978.2（14）A°^3, Z = 4, Dc = 1.618 g/cm^3, μ = 1.160 mm^-1, F（000） = 964, the final R = 0.0449 and w R = 0.1443 with I 〉 2σ（I）. Magnetic measurements show that 1 exhibits antiferromagnetic interactions by the analysis of magnetic test data.

Synthesis, Crystal Structure, Magnetic Property and DFT Study of a Novel 2D Polymer [Cu(pdc)(bpy)]·H_2O

A new copper complex [Cu（pdc）（bpy）]·H2 O（1, H2 pdc = 3,5-pyridinedicarboxylic acid, bpy = 2,2-bipyridine） has been solvothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, UV-vis spectroscopy and magnetic measure- ments. Complex 1 crystallizes in monoclinic system, space group P21 /c, a = 10.893（2）, b = 7.3641（15）, c = 1.9921（4）, β = 92.16（3）, V = 1596.9（6）3, Dc = 1.676 g/cm3, Mr = 402.84, Z = 4, F（000） = 820, μ = 1.404 mm-1, the final R = 0.0237 and wR = 0.0693. The Cu（II） ion is five-coordinated by two O atoms from two pdc ligands, one N atom from another pdc ligand and two N atoms from the bpy ligand. The pdc anion, which acts as a tridentate ligand, links three Cu ions, forming（3,3）-connected two-dimensional（2D） sheets. We also studied the electronic structure and orbital energies of complex 1 by DFT methods, and the results are consistent with UV-vis spectrum.

Hydrothermal synthesis and magnetic property of NaV_2O_5 nanorods

One dimensional rod like NaV 2O 5 was synthesized by hydrothermal method, which draws much attention as an exotic spin Peierls compound. The samples have been characterized by X ray diffraction (XRD), transmission election microscopy (TEM), and magnetic susceptibility measurements. The pH value and the reducing agent are critical for synthesizing NaV 2O 5 nanorods. The reducing agent NH 2OH may play a key role in the assembly and growth of nanorods of products. [

Synthesis,Crystal Structure and Magnetic Property of Ternary Neodymium Zirconium Sulfide,Nd2ZrS5

A new ternary neodymium zirconium sulfide Nd_2ZrS_5 was synthesized by high-temperature solid-state reaction and structurally characterized by single-crystal X-ray diffraction. It crystallizes in the orthorhombic space group Pnma（No. 62） belonging to the Y_2HfS_5 structure-type with a = 11.461（4）, b = 8.009（3）, c = 7.315（3） A, Z = 2 and V = 671.5（4）A3. Its structure features NdS_8 and ZrS_7 polyhedra-constructed a 3-D network. The data of magnetic susceptibility indicate its antiferromagnetic-like behavior without magnetic order down to 2 K.