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
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
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
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..
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.
