In recent years,the organometallic ehemistry of the lanthanide metals in low oxidation states has beenactively investigated.The synthesis of the low一valent lanthanide eomPlexes has the signifieant meanings ontheory a...In recent years,the organometallic ehemistry of the lanthanide metals in low oxidation states has beenactively investigated.The synthesis of the low一valent lanthanide eomPlexes has the signifieant meanings ontheory and praeti展开更多
The crystal structure of lisiguangite, CuPtBiS3, from Yanshan mountains, Chengde Prefecture, Hebei Province, China has been determined by single crystal X-ray diffraction. It belongs to orthorhombic space group P21212...The crystal structure of lisiguangite, CuPtBiS3, from Yanshan mountains, Chengde Prefecture, Hebei Province, China has been determined by single crystal X-ray diffraction. It belongs to orthorhombic space group P212121 with a = 7.7372(15)A, b = 12.844(3) A, c -- 4.9062(10) A, V = 487.57(17) A^3, Z = 4. The final full-matric least-square refinement on F2 converged with R1 = 0.0495 and wR2 = 0.0992 for 704 observed reflections [I≥2σ(I)]. Lisiguangite is the isomorph of known CuNiSbS3 and CuNiBiS3. Pt^2+ and Bi^3+ have the distorted octahedral coordination enviroments composed of two metal and four S and Cu^+2 has a distorted tetrahedrai coordination environment with four S atoms. Each S atom is surrounded by four metals to give a tetrahedral environment. The crystal structure is a complex 3 dimensional network.展开更多
Guided by the theoretical prediction,a new MAX phase V2SnC was synthesized experimentally for the first time by reaction of V,Sn,and C mixtures at 1000°C.The chemical composition and crystal structure of this new...Guided by the theoretical prediction,a new MAX phase V2SnC was synthesized experimentally for the first time by reaction of V,Sn,and C mixtures at 1000°C.The chemical composition and crystal structure of this new compound were identified by the cross-check combination of first-principles calculations,X-ray diffraction(XRD),energy dispersive X-ray spectroscopy(EDS),and high resolution scanning transmission electron microscopy(HR-STEM).The stacking sequence of V2C and Sn layers results in a crystal structure of space group P63/mmc.The a-and c-lattice parameters,which were determined by the Rietveld analysis of powder XRD pattern,are 0.2981(0)nm and 1.3470(6)nm,respectively.The atomic positions are V at 4f(1/3,2/3,0.0776(5)),Sn at 2d(2/3,1/3,1/4),and C at 2a(0,0,0).A new set of XRD data of V2SnC was also obtained.Theoretical calculations suggest that this new compound is stable with negative formation energy and formation enthalpy,satisfied Born-Huang criteria of mechanical stability,and positive phonon branches over the Brillouin zone.It also has low shear deformation resistance c44(second-order elastic constant,cij)and shear modulus(G),positive Cauchy pressure,and low Pugh’s ratio(G/B=0.500<0.571),which is regarded as a quasi-ductile MAX phase.The mechanism underpinning the quasi-ductility is associated with the presence of a metallic bond.展开更多
The crystal structure of a new mineral of the stibnite group, Sb-2Se-3, has been determined. The cell constants, obtained by least-squares calculation from direct θ -value’s measurements on the diffractometer are: a...The crystal structure of a new mineral of the stibnite group, Sb-2Se-3, has been determined. The cell constants, obtained by least-squares calculation from direct θ -value’s measurements on the diffractometer are: a =1.158 8(5), b =1.174 4(4), c =0.395 5(2) nm; orthorhombic; V =0.538 23 nm+3; Z =4. The space group is Pbnm. X-ray single crystal data, using Mo K α radiation, were measured on a RIGAKU RASA-5RP automated diffractometer and refined to a final R index of 0.048 1. Sb-2Se-3 is isostructural with Sb-2S-3 and Bi-2S-3. Each Sb(1) atom is six-coordinated by 3 Se(1), 1 Se(2) and 2 Se(3) atoms at distances 0.266 0-0.323 6 nm. Each Sb(2) atom is seven-coordinated by 2 Se(1), 2 Se(2) and 3 Se(3) atoms at distances of 0.258 1- 0.346 7 nm. The crystal structure consists of chains parallel to c or needle axis. The strongest bonds (shortest separations) are within the chains. Many important physical properties of antimonselite (optical, ferroelectric, etc.) are related to its crystal structure.展开更多
There is a type of complex oxide mineral, composed of many elements such as Sn, Mg, Fe, Zn, Ti, Mn, Al, etc., in the areas of Anhua, Linwu and Shizhuyuan of Hunan Province. These minerals belong to nigerite, Mg-nigeri...There is a type of complex oxide mineral, composed of many elements such as Sn, Mg, Fe, Zn, Ti, Mn, Al, etc., in the areas of Anhua, Linwu and Shizhuyuan of Hunan Province. These minerals belong to nigerite, Mg-nigerite (pengzhizhongite), etc.. According to the principle of closest packing, the crystal chemical properties of nigerite (brown), pengzhizhongite (buff), Zn-nigerite (fawn), Fe-nigerite, Mn-nigerite (greenish-black) etc. have been analyzed. Their crystal structures may be characterized by O (the layers of cation octahedral coordinations), T_1 (the mixed layers of cation octahedral coordinations and cation tetrahedral coordinations in same directions), T_2 (the mixed layers of cation octahedral coordinations and cation tetrahedral coordination in different directions). The position of layer-O and layer-T is alternate permutation. The crystal structure of pengzhizhongite (6 H ) may be expressed by …OT_2OT_1OT_1…, taaffeite (8 H ), …OT_2OT_1OT_2OT_1…, and nigerite (24 R ), … OT_1OT_2 OT_2OT_1 …×3 etc.. In their structure, there are not only the crystal structure units of spinel … OT_2 OT_2 … but also the units of nolanite … OT_1 OT_1 …. The research of these minerals has important theoretic and practical significance in the fields of minerals, gemology, material science etc..展开更多
A new cerite group mineral species,taipingite-(Ce),ideally(Ce7^3+,Ca2)∑9Mg(SiO4)3[SiO3(OH)]4 F3,has been found in the Taipingzhen rare earth element(REE)deposit in the North Qinling Orogen(NQO),Central China.It forms...A new cerite group mineral species,taipingite-(Ce),ideally(Ce7^3+,Ca2)∑9Mg(SiO4)3[SiO3(OH)]4 F3,has been found in the Taipingzhen rare earth element(REE)deposit in the North Qinling Orogen(NQO),Central China.It forms subhedral grains(up to approximately 100 μm×200 μm)commonly intergrown with the REE mineral assemblages and is closely associated with allanite-(Ce),gatelite-(Ce),tornebohmite-(Ce),fluocerite-(Ce),fluocerite-(La),fluorite,bastnasite-(Ce),parisite-(Ce)and calcite.Taipingite-(Ce)is light red to pinkish brown under a binocular microscope and pale brown to colorless in thin section,and it is translucent to transparent with a grayish-white streak and vitreous luster.This mineral is brittle with conchoidal fracture;has a Mohs hardness value of approximately 51/2 and exhibits no cleavage twinning or parting.The calculated density is 4.900(5)g/cm3.Optically,taipingite-(Ce)is uniaxial(+),withω=1.808(5),ε=1.812(7),c=ε,and a=b=ω.Furthermore,this mineral is insoluble in HCl,HNO3 and H2 SO4.Electron microprobe analysis demonstrated that the sample was relatively pure,yielding the empirical formula(with calculated H2 O):(Ce4.02La1.64Nd1.49Pr0.41Sm0.10Gd0.02Ho0.02Tm0.01Lu0.02Y0.03Ca0.66Mg0.05Th(0.01-0.51∑9(Mg0.75Fe0.253+)∑1(SiO4)3{[SiO3(OH)]3.98[PO3(OH)]0.02}∑4(F1.81OH1.17Cl0.02∑3.Taipingite-(Ce)is trigonal and exhibits space group symmetry R3 c with unit cell parameters a=10.7246(3)Å,c=37.9528(14)Å,V=3780.39(20)Å3 and Z=6.The strongest eight lines in the X-ray diffraction pattern are[d in A(I)(hkl)]:4.518(50)(202),3.455(95)(122),3.297(85)(214),3.098(35)(300),2.941(100)(02,10),2.683(65)(220),1.945(40)(238)and 1.754(40)(30,18).The crystal structure has been refined to a R1 factor of 0.025,calculated for the 2312 unique observed reflections(Fo≥4σ).The mineral is named after its discovery locality and is characterized as the F-dominant analogue of cerite-(Ce).展开更多
A polynuclear complex containing a monomer of Cu(Ⅱ)-Zn(Ⅱ) heterobinuclear unit was synthesized and characterized by IR spectra and magnetic moment. The crystal and molecular structure of the complex, CuZnC_(19)H_(24...A polynuclear complex containing a monomer of Cu(Ⅱ)-Zn(Ⅱ) heterobinuclear unit was synthesized and characterized by IR spectra and magnetic moment. The crystal and molecular structure of the complex, CuZnC_(19)H_(24)Cl_4N_2O_2, was determined by X-ray diffraction, it crystallized in monoclinic, P2_1 / m, a = 8.812 (2), b = 15.972(3), c = 8.831(1) A, β = 114.33(1)°, V = 1132.4A^3, Z=2, D_c= 1.710 g / cm^3, λ(Mo K_α) = 0.71073A, μ = 25.227 cm^(-1), R = 0.051. R_w = 0.063 for 1130 ob- served reflections with I> 3σ(I) . The coordinated octahedra of Cu(Ⅱ) and tetrahedra of Zn(Ⅱ) via bridging Cl atoms form a single chain polynuclear complex. The Cu, Zn and bridging Cl atoms are located on the crystallographic symmetry plane m which is perpendicular to 2N and 2O donor plane.展开更多
8,8′-Dibromo-6,6′, 7,7′-tetramethoxy-5,5′-diisopropyl-3,3′-oxydimethylene dinaphtho[2,1- b:2′, 1′-d]furan, C_(32)H_(30)Br_2O_; M. W.=670; triclinic; space group P1; a=8.896(2), b=10.216(1), c= 10.423(1)A, α=10...8,8′-Dibromo-6,6′, 7,7′-tetramethoxy-5,5′-diisopropyl-3,3′-oxydimethylene dinaphtho[2,1- b:2′, 1′-d]furan, C_(32)H_(30)Br_2O_; M. W.=670; triclinic; space group P1; a=8.896(2), b=10.216(1), c= 10.423(1)A, α=108.48(1), β=119.36(1), γ=99.26(1); V=723.5A^3; Z=1, D_(cal.)=1.479 g.cm^(-3). Mo K_α=28.11cm^(-1), F(000)=326, T=293K. The structure was solved by direct method and full-matrix least-squares refinement converged at R=0.034 for 2377 observed reflections. The oxygen atom in seven-membered ring exists in a disordered arrangement. Both bisnaphthalene and oxygen-containing five-membered ring have planar conformations with dihedral angle 6°, showing marked aromatic feature.展开更多
The synthesis and the structural characterization of the title compound HNa[WO(CCH)-(OCCH)(HO)][HWO]·13.5 HO are described.It is known that the mixed oxo-ethylidyne-capped tritungsten cluster can be obtaine...The synthesis and the structural characterization of the title compound HNa[WO(CCH)-(OCCH)(HO)][HWO]·13.5 HO are described.It is known that the mixed oxo-ethylidyne-capped tritungsten cluster can be obtained by Zn dust reduction of NaWO·2HO in acetic anhydride.The title compound has been characterized by X-ray diffraction,UV/VIS andH NMR spectra.The tungsten atoms in the cluster cation and anion are in the oxidation states of W(IV)and W(VI)respectively.The crystal is rhombohedral with the space group R32,a=17.058(3),c=49.665(9),γ=120°,V=12516(9),Z=6,final R=0.037 for 2071 reflections with I≥3σ(I).Boththe cluster cation and anion have a Csymmetry.The important interatomic distances in angstroms forthe cluster cation are:W—W,2.730(2);W—μ-O,2.00;W—O(carboxyl),2.12;W—O,2.18(2).展开更多
文摘In recent years,the organometallic ehemistry of the lanthanide metals in low oxidation states has beenactively investigated.The synthesis of the low一valent lanthanide eomPlexes has the signifieant meanings ontheory and praeti
文摘The crystal structure of lisiguangite, CuPtBiS3, from Yanshan mountains, Chengde Prefecture, Hebei Province, China has been determined by single crystal X-ray diffraction. It belongs to orthorhombic space group P212121 with a = 7.7372(15)A, b = 12.844(3) A, c -- 4.9062(10) A, V = 487.57(17) A^3, Z = 4. The final full-matric least-square refinement on F2 converged with R1 = 0.0495 and wR2 = 0.0992 for 704 observed reflections [I≥2σ(I)]. Lisiguangite is the isomorph of known CuNiSbS3 and CuNiBiS3. Pt^2+ and Bi^3+ have the distorted octahedral coordination enviroments composed of two metal and four S and Cu^+2 has a distorted tetrahedrai coordination environment with four S atoms. Each S atom is surrounded by four metals to give a tetrahedral environment. The crystal structure is a complex 3 dimensional network.
基金This study is supported by Thousand Talents Program of Sichuan Province,the Open Project of State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials(17kffk01)Outstanding Young Scientific and Technical Talents in Sichuan Province(2019JDJQ0009)and the National Natural Science Foundation of China(No.51741208).
文摘Guided by the theoretical prediction,a new MAX phase V2SnC was synthesized experimentally for the first time by reaction of V,Sn,and C mixtures at 1000°C.The chemical composition and crystal structure of this new compound were identified by the cross-check combination of first-principles calculations,X-ray diffraction(XRD),energy dispersive X-ray spectroscopy(EDS),and high resolution scanning transmission electron microscopy(HR-STEM).The stacking sequence of V2C and Sn layers results in a crystal structure of space group P63/mmc.The a-and c-lattice parameters,which were determined by the Rietveld analysis of powder XRD pattern,are 0.2981(0)nm and 1.3470(6)nm,respectively.The atomic positions are V at 4f(1/3,2/3,0.0776(5)),Sn at 2d(2/3,1/3,1/4),and C at 2a(0,0,0).A new set of XRD data of V2SnC was also obtained.Theoretical calculations suggest that this new compound is stable with negative formation energy and formation enthalpy,satisfied Born-Huang criteria of mechanical stability,and positive phonon branches over the Brillouin zone.It also has low shear deformation resistance c44(second-order elastic constant,cij)and shear modulus(G),positive Cauchy pressure,and low Pugh’s ratio(G/B=0.500<0.571),which is regarded as a quasi-ductile MAX phase.The mechanism underpinning the quasi-ductility is associated with the presence of a metallic bond.
文摘The crystal structure of a new mineral of the stibnite group, Sb-2Se-3, has been determined. The cell constants, obtained by least-squares calculation from direct θ -value’s measurements on the diffractometer are: a =1.158 8(5), b =1.174 4(4), c =0.395 5(2) nm; orthorhombic; V =0.538 23 nm+3; Z =4. The space group is Pbnm. X-ray single crystal data, using Mo K α radiation, were measured on a RIGAKU RASA-5RP automated diffractometer and refined to a final R index of 0.048 1. Sb-2Se-3 is isostructural with Sb-2S-3 and Bi-2S-3. Each Sb(1) atom is six-coordinated by 3 Se(1), 1 Se(2) and 2 Se(3) atoms at distances 0.266 0-0.323 6 nm. Each Sb(2) atom is seven-coordinated by 2 Se(1), 2 Se(2) and 3 Se(3) atoms at distances of 0.258 1- 0.346 7 nm. The crystal structure consists of chains parallel to c or needle axis. The strongest bonds (shortest separations) are within the chains. Many important physical properties of antimonselite (optical, ferroelectric, etc.) are related to its crystal structure.
基金ThispaperissupportedbytheNationalNaturalScienceFoundationofChina (No .492 72 0 91 )
文摘There is a type of complex oxide mineral, composed of many elements such as Sn, Mg, Fe, Zn, Ti, Mn, Al, etc., in the areas of Anhua, Linwu and Shizhuyuan of Hunan Province. These minerals belong to nigerite, Mg-nigerite (pengzhizhongite), etc.. According to the principle of closest packing, the crystal chemical properties of nigerite (brown), pengzhizhongite (buff), Zn-nigerite (fawn), Fe-nigerite, Mn-nigerite (greenish-black) etc. have been analyzed. Their crystal structures may be characterized by O (the layers of cation octahedral coordinations), T_1 (the mixed layers of cation octahedral coordinations and cation tetrahedral coordinations in same directions), T_2 (the mixed layers of cation octahedral coordinations and cation tetrahedral coordination in different directions). The position of layer-O and layer-T is alternate permutation. The crystal structure of pengzhizhongite (6 H ) may be expressed by …OT_2OT_1OT_1…, taaffeite (8 H ), …OT_2OT_1OT_2OT_1…, and nigerite (24 R ), … OT_1OT_2 OT_2OT_1 …×3 etc.. In their structure, there are not only the crystal structure units of spinel … OT_2 OT_2 … but also the units of nolanite … OT_1 OT_1 …. The research of these minerals has important theoretic and practical significance in the fields of minerals, gemology, material science etc..
基金financially supported by the National Natural Science Foundation of China(Grant No.41502033)the China Geological Survey(DD20160129-3,1212011120771,DD20190813)。
文摘A new cerite group mineral species,taipingite-(Ce),ideally(Ce7^3+,Ca2)∑9Mg(SiO4)3[SiO3(OH)]4 F3,has been found in the Taipingzhen rare earth element(REE)deposit in the North Qinling Orogen(NQO),Central China.It forms subhedral grains(up to approximately 100 μm×200 μm)commonly intergrown with the REE mineral assemblages and is closely associated with allanite-(Ce),gatelite-(Ce),tornebohmite-(Ce),fluocerite-(Ce),fluocerite-(La),fluorite,bastnasite-(Ce),parisite-(Ce)and calcite.Taipingite-(Ce)is light red to pinkish brown under a binocular microscope and pale brown to colorless in thin section,and it is translucent to transparent with a grayish-white streak and vitreous luster.This mineral is brittle with conchoidal fracture;has a Mohs hardness value of approximately 51/2 and exhibits no cleavage twinning or parting.The calculated density is 4.900(5)g/cm3.Optically,taipingite-(Ce)is uniaxial(+),withω=1.808(5),ε=1.812(7),c=ε,and a=b=ω.Furthermore,this mineral is insoluble in HCl,HNO3 and H2 SO4.Electron microprobe analysis demonstrated that the sample was relatively pure,yielding the empirical formula(with calculated H2 O):(Ce4.02La1.64Nd1.49Pr0.41Sm0.10Gd0.02Ho0.02Tm0.01Lu0.02Y0.03Ca0.66Mg0.05Th(0.01-0.51∑9(Mg0.75Fe0.253+)∑1(SiO4)3{[SiO3(OH)]3.98[PO3(OH)]0.02}∑4(F1.81OH1.17Cl0.02∑3.Taipingite-(Ce)is trigonal and exhibits space group symmetry R3 c with unit cell parameters a=10.7246(3)Å,c=37.9528(14)Å,V=3780.39(20)Å3 and Z=6.The strongest eight lines in the X-ray diffraction pattern are[d in A(I)(hkl)]:4.518(50)(202),3.455(95)(122),3.297(85)(214),3.098(35)(300),2.941(100)(02,10),2.683(65)(220),1.945(40)(238)and 1.754(40)(30,18).The crystal structure has been refined to a R1 factor of 0.025,calculated for the 2312 unique observed reflections(Fo≥4σ).The mineral is named after its discovery locality and is characterized as the F-dominant analogue of cerite-(Ce).
文摘A polynuclear complex containing a monomer of Cu(Ⅱ)-Zn(Ⅱ) heterobinuclear unit was synthesized and characterized by IR spectra and magnetic moment. The crystal and molecular structure of the complex, CuZnC_(19)H_(24)Cl_4N_2O_2, was determined by X-ray diffraction, it crystallized in monoclinic, P2_1 / m, a = 8.812 (2), b = 15.972(3), c = 8.831(1) A, β = 114.33(1)°, V = 1132.4A^3, Z=2, D_c= 1.710 g / cm^3, λ(Mo K_α) = 0.71073A, μ = 25.227 cm^(-1), R = 0.051. R_w = 0.063 for 1130 ob- served reflections with I> 3σ(I) . The coordinated octahedra of Cu(Ⅱ) and tetrahedra of Zn(Ⅱ) via bridging Cl atoms form a single chain polynuclear complex. The Cu, Zn and bridging Cl atoms are located on the crystallographic symmetry plane m which is perpendicular to 2N and 2O donor plane.
文摘8,8′-Dibromo-6,6′, 7,7′-tetramethoxy-5,5′-diisopropyl-3,3′-oxydimethylene dinaphtho[2,1- b:2′, 1′-d]furan, C_(32)H_(30)Br_2O_; M. W.=670; triclinic; space group P1; a=8.896(2), b=10.216(1), c= 10.423(1)A, α=108.48(1), β=119.36(1), γ=99.26(1); V=723.5A^3; Z=1, D_(cal.)=1.479 g.cm^(-3). Mo K_α=28.11cm^(-1), F(000)=326, T=293K. The structure was solved by direct method and full-matrix least-squares refinement converged at R=0.034 for 2377 observed reflections. The oxygen atom in seven-membered ring exists in a disordered arrangement. Both bisnaphthalene and oxygen-containing five-membered ring have planar conformations with dihedral angle 6°, showing marked aromatic feature.
基金the National Natural Science Foundation of China.
文摘The synthesis and the structural characterization of the title compound HNa[WO(CCH)-(OCCH)(HO)][HWO]·13.5 HO are described.It is known that the mixed oxo-ethylidyne-capped tritungsten cluster can be obtained by Zn dust reduction of NaWO·2HO in acetic anhydride.The title compound has been characterized by X-ray diffraction,UV/VIS andH NMR spectra.The tungsten atoms in the cluster cation and anion are in the oxidation states of W(IV)and W(VI)respectively.The crystal is rhombohedral with the space group R32,a=17.058(3),c=49.665(9),γ=120°,V=12516(9),Z=6,final R=0.037 for 2071 reflections with I≥3σ(I).Boththe cluster cation and anion have a Csymmetry.The important interatomic distances in angstroms forthe cluster cation are:W—W,2.730(2);W—μ-O,2.00;W—O(carboxyl),2.12;W—O,2.18(2).