Methane fluxes from late rice and single cropping rice fields in Taihu region were measured using closedchamber method in 1992 and 1993 and CH_4 emission from this region (total area of paddy soils was about1.88 milli...Methane fluxes from late rice and single cropping rice fields in Taihu region were measured using closedchamber method in 1992 and 1993 and CH_4 emission from this region (total area of paddy soils was about1.88 million hectares, of which 0.63 million hectares are distributed in the south of Jiangsu Province) wasestimated on the basis of the mean CH_4 fluxes observed. The results showed that the mean CH_4 flaxes fromlate rice and single cropping rice field were quite similar under the prevailing cultivation practices in theregion, being around 5 mg CH_4/m￣2/h (4.31-5.31 mg CH_4/m￣2/h for various cultivars of the late rice and3.20-6.22 mg CH_4/m￣2/h for various treatments of the single cropping rice). Total CH_4 emission from paddysoils in the region was estimated to be 0.185-0.359 Tg CH_4 per year. Continuously flooding the soil witha water layer till ripening caused higher mean CH_4 flux; and addition of nitrification inhibitor (thiourea)stimulated CH_4 emission. There was no simple relationship between CH_4 flux and either soil temperature orsoil Eh.展开更多
Two organically templated uranium phosphites, （C4H12N）（UO2）（HPO3）（NO3） （Mr = 486.16） 1 and （C16H36N）2（UO2）2（H2PO3）2（HPO3）（NO3）2 （Mr= 1390.95） 2, were prepared by evaporation from aqueous solution...Two organically templated uranium phosphites, （C4H12N）（UO2）（HPO3）（NO3） （Mr = 486.16） 1 and （C16H36N）2（UO2）2（H2PO3）2（HPO3）（NO3）2 （Mr= 1390.95） 2, were prepared by evaporation from aqueous solution of uranyl nitrate, phosphite acid and their respective organic ammonium hydroxids. Their structures were determined by single-crystal X-ray diffraction and further characterized by infrared and fluorescence spectroscopy. In 1, pentagonal [UO7] bipyramids share comers with three [HPO3]2- tetrahedra and one edge with a [NO3]- anion to form [（UO2）- （HPO3）（NO3）]^- ladder-like chains parallel to the b axis. The structure of 2 is also based upon one-dimensional anionic [（UO2）2（H2PO3）2（HPO3）（NO3）2]2-chains of comer-sharing penta- gonal [UOT] bipyramids with [H2PO3]- and [HPO3] tetrahedra, which is still unknown in structural chemistry of uranium so far. Crystal data for 1： monoclinic, space group C2/m, a = 21.808（7）, b = 6.9605（15）, c = 8.357（2） A, β = 98.327（15）°, V= 1255.2（6） A^3, Z = 4, Dc = 2.573 g/cm^3, F（000） = 888, μ = 13.086 mm^-1 the final R = 0.0418 and wR = 0.0906 （I 〉 2σ（I））; and those for 2： monoclinic, space group C2/c, a = 36.4549（8）, b = 14.5296（11）, c = 20.8253（11） A, β = 101.7440（8）°, V= 10799.7（10） A3, Z = 8, Dc= 1.711 g/cm^3, F（000） = 5424,μ = 6.144 mm^-1, the final R= 0.0368 and wR= 0.0865 （I〉 2σ（I））.展开更多
The title compound has been synthesized by the reaction of(NH4)3VS4, CuBr and NMe4Br in pyridine and its structure was determined by singlecrystal X-ray diffraction. Crystallographic data: C40H40Br3Cu6N8S4V, M4= 1432....The title compound has been synthesized by the reaction of(NH4)3VS4, CuBr and NMe4Br in pyridine and its structure was determined by singlecrystal X-ray diffraction. Crystallographic data: C40H40Br3Cu6N8S4V, M4= 1432. 95,orthorhombic space group Fdd2, a= 29. 9519 (2), b=13. 4719 (2), c= 25. 8612 (4)A, V= 10435. 2 (4), Z= 8, Dc= 1.824 g/cm3, F(000)= 5616,μ(MoKa) =50.64 cm-1, the final R =0.091 and wR =0. 206 for those 3401 unique reflectionshaving . The crystal structure determination shows that the cluster consists of a tetrahedral VS4 core encapsulated by a distorted octahedral array of six copperatoms which have two different coordination geometries, trigonal and tetrahedral.展开更多
The title V-Cu-S heterometallic cluster compound C84 H86Cl4Cu6N2O4P4S6V2, crystallizes in the monoclinic space group P21/n with a=16.381(5), b=17.114(3),c=16.749(6) A,β=107. 04(3)°,V=4490(2)A3, Mr=2128.84,Z=2,Dc...The title V-Cu-S heterometallic cluster compound C84 H86Cl4Cu6N2O4P4S6V2, crystallizes in the monoclinic space group P21/n with a=16.381(5), b=17.114(3),c=16.749(6) A,β=107. 04(3)°,V=4490(2)A3, Mr=2128.84,Z=2,Dc=1. 57 g/cm3,μ= 19. 6 cm-1,F(000)=2160. Final R=0.074(Rw=0.082) for 2662 unique reflections with I≥3σ(I). The V atom in the compound retains the tetrahedral geometry of the VS3O with S-V-S or S-V-O angles of 108.6(6)～110.3 (6)°.The cluster core [V2Cu6S6O2] of the compound can be regarded as two cluster cores [VCu3S3O] bonded by bondings of the Cu-Cu'(distances of 2.774(3)～2.707(5) A) and Cu-S (distances of 2.463(7)～2.396(9) A) with centrosymmetric. Atoms of the cluster core V2Cu6 form a distorted cube with the Cu Cu'or the V-Cu distances of 2. 774(3)～2. 707(5) A.展开更多
Catena-[bis (3-methyl-4-nitropyridine N-oxide ) cadmiumdichloride],[Cd(C_6H_6N_2O_3)_2Cl_2], M_r= 491. 56, monoclinic , P2_1, a= 3. 799 (3), b= 29. 231 ( 9),c=7. 679(5) A, β=100. 19(6)°, V=839. 4 A￣3, Z=2, D_c=...Catena-[bis (3-methyl-4-nitropyridine N-oxide ) cadmiumdichloride],[Cd(C_6H_6N_2O_3)_2Cl_2], M_r= 491. 56, monoclinic , P2_1, a= 3. 799 (3), b= 29. 231 ( 9),c=7. 679(5) A, β=100. 19(6)°, V=839. 4 A￣3, Z=2, D_c= 1. 94 g/cm￣3, λ(MoKa)= 0. 71069 A, F(000) =484, P(MoKa) = 16. 5 cm￣(-1), final R=0. 038 for 1202 Observed reflections, T= 296K. The Cd atom is octahedrally coordinated by two O atoms from the trans 3-methyl-4-nitropyridine N-oxide (pom) ligands in the axial positions and four Cl atoms lying in the equatorial plane. The coordination octahedra form chains along the short a axis by edge sharing through the Cl atoms.展开更多
文摘Methane fluxes from late rice and single cropping rice fields in Taihu region were measured using closedchamber method in 1992 and 1993 and CH_4 emission from this region (total area of paddy soils was about1.88 million hectares, of which 0.63 million hectares are distributed in the south of Jiangsu Province) wasestimated on the basis of the mean CH_4 fluxes observed. The results showed that the mean CH_4 flaxes fromlate rice and single cropping rice field were quite similar under the prevailing cultivation practices in theregion, being around 5 mg CH_4/m￣2/h (4.31-5.31 mg CH_4/m￣2/h for various cultivars of the late rice and3.20-6.22 mg CH_4/m￣2/h for various treatments of the single cropping rice). Total CH_4 emission from paddysoils in the region was estimated to be 0.185-0.359 Tg CH_4 per year. Continuously flooding the soil witha water layer till ripening caused higher mean CH_4 flux; and addition of nitrification inhibitor (thiourea)stimulated CH_4 emission. There was no simple relationship between CH_4 flux and either soil temperature orsoil Eh.
文摘Two organically templated uranium phosphites, （C4H12N）（UO2）（HPO3）（NO3） （Mr = 486.16） 1 and （C16H36N）2（UO2）2（H2PO3）2（HPO3）（NO3）2 （Mr= 1390.95） 2, were prepared by evaporation from aqueous solution of uranyl nitrate, phosphite acid and their respective organic ammonium hydroxids. Their structures were determined by single-crystal X-ray diffraction and further characterized by infrared and fluorescence spectroscopy. In 1, pentagonal [UO7] bipyramids share comers with three [HPO3]2- tetrahedra and one edge with a [NO3]- anion to form [（UO2）- （HPO3）（NO3）]^- ladder-like chains parallel to the b axis. The structure of 2 is also based upon one-dimensional anionic [（UO2）2（H2PO3）2（HPO3）（NO3）2]2-chains of comer-sharing penta- gonal [UOT] bipyramids with [H2PO3]- and [HPO3] tetrahedra, which is still unknown in structural chemistry of uranium so far. Crystal data for 1： monoclinic, space group C2/m, a = 21.808（7）, b = 6.9605（15）, c = 8.357（2） A, β = 98.327（15）°, V= 1255.2（6） A^3, Z = 4, Dc = 2.573 g/cm^3, F（000） = 888, μ = 13.086 mm^-1 the final R = 0.0418 and wR = 0.0906 （I 〉 2σ（I））; and those for 2： monoclinic, space group C2/c, a = 36.4549（8）, b = 14.5296（11）, c = 20.8253（11） A, β = 101.7440（8）°, V= 10799.7（10） A3, Z = 8, Dc= 1.711 g/cm^3, F（000） = 5424,μ = 6.144 mm^-1, the final R= 0.0368 and wR= 0.0865 （I〉 2σ（I））.
文摘The title compound has been synthesized by the reaction of(NH4)3VS4, CuBr and NMe4Br in pyridine and its structure was determined by singlecrystal X-ray diffraction. Crystallographic data: C40H40Br3Cu6N8S4V, M4= 1432. 95,orthorhombic space group Fdd2, a= 29. 9519 (2), b=13. 4719 (2), c= 25. 8612 (4)A, V= 10435. 2 (4), Z= 8, Dc= 1.824 g/cm3, F(000)= 5616,μ(MoKa) =50.64 cm-1, the final R =0.091 and wR =0. 206 for those 3401 unique reflectionshaving . The crystal structure determination shows that the cluster consists of a tetrahedral VS4 core encapsulated by a distorted octahedral array of six copperatoms which have two different coordination geometries, trigonal and tetrahedral.
文摘The title V-Cu-S heterometallic cluster compound C84 H86Cl4Cu6N2O4P4S6V2, crystallizes in the monoclinic space group P21/n with a=16.381(5), b=17.114(3),c=16.749(6) A,β=107. 04(3)°,V=4490(2)A3, Mr=2128.84,Z=2,Dc=1. 57 g/cm3,μ= 19. 6 cm-1,F(000)=2160. Final R=0.074(Rw=0.082) for 2662 unique reflections with I≥3σ(I). The V atom in the compound retains the tetrahedral geometry of the VS3O with S-V-S or S-V-O angles of 108.6(6)～110.3 (6)°.The cluster core [V2Cu6S6O2] of the compound can be regarded as two cluster cores [VCu3S3O] bonded by bondings of the Cu-Cu'(distances of 2.774(3)～2.707(5) A) and Cu-S (distances of 2.463(7)～2.396(9) A) with centrosymmetric. Atoms of the cluster core V2Cu6 form a distorted cube with the Cu Cu'or the V-Cu distances of 2. 774(3)～2. 707(5) A.
文摘Catena-[bis (3-methyl-4-nitropyridine N-oxide ) cadmiumdichloride],[Cd(C_6H_6N_2O_3)_2Cl_2], M_r= 491. 56, monoclinic , P2_1, a= 3. 799 (3), b= 29. 231 ( 9),c=7. 679(5) A, β=100. 19(6)°, V=839. 4 A￣3, Z=2, D_c= 1. 94 g/cm￣3, λ(MoKa)= 0. 71069 A, F(000) =484, P(MoKa) = 16. 5 cm￣(-1), final R=0. 038 for 1202 Observed reflections, T= 296K. The Cd atom is octahedrally coordinated by two O atoms from the trans 3-methyl-4-nitropyridine N-oxide (pom) ligands in the axial positions and four Cl atoms lying in the equatorial plane. The coordination octahedra form chains along the short a axis by edge sharing through the Cl atoms.
