The title compound [Ag(CH3CONHC(S)NH2)2](NO3) has been prepared by hydrothermal synthesis and characterized by single-crystal X-ray diffraction. It crystallizes in mo-noclinic, space group P21/c with Mr = 406.20 (C6H1...The title compound [Ag(CH3CONHC(S)NH2)2](NO3) has been prepared by hydrothermal synthesis and characterized by single-crystal X-ray diffraction. It crystallizes in mo-noclinic, space group P21/c with Mr = 406.20 (C6H12Ag N5O5S2), a = 12.0680(6), b = 6.8056(5), c = 18.0173(1) ? b = 111.383(4), V = 1377.9(2) 3, Z = 4, Dc = 1.958 g/cm3 , F(000) = 808, = 1.789 mm-1, R = 0.0361 and wR = 0.1015. Of 4185 reflections ((2)max = 55.00?, 3147 were unique (Rint = 0.0174) and 2820 with I > 2(I) were used to solve the structure. The silver(I) atom adopts V-shape geometry with the AgS bond distance of 2.4271(7) and 2.7229(9) , respectively. Seven atoms of one acetylthiocarbamide ligand are coplanar, while only four atoms of another acetylthio-carbamide ligand are fairly planar. The [Ag(CH3CONHC(S)NH2)2]+ cation and nitrate anion NO3- are connected by hydrogen bonds to form a three dimensional hydrogen bonding network..展开更多
Inorganic solid electrolytes have distinguished advantages in terms of safety and stability, and are promising to substitute for conventional organic liquid electrolytes. However, low ionic conductivity of typical can...Inorganic solid electrolytes have distinguished advantages in terms of safety and stability, and are promising to substitute for conventional organic liquid electrolytes. However, low ionic conductivity of typical candidates is the key problem. As connective diffusion path is the prerequisite for high performance, we screen for possible solid electrolytes from the 2004 International Centre for Diffraction Data （ICDD） database by calculating conduction pathways using Bond Valence （BV） method. There are 109846 inorganic crystals in the 2004 ICDD database, and 5295 of them contain lithium. Except for those with toxic, radioactive, rare, or variable valence elements, 1380 materials are candidates for solid electrolytes. The rationality of the BV method is approved by comparing the existing solid electrolytes＇ conduction pathways we had calculated with those from ex- periments or first principle calculations. The implication for doping and substitution, two important ways to improve the conductivity, is also discussed. Among them LizCO3 is selected for a detailed comparison, and the pathway is reproduced well with that based on the density functional studies. To reveal the correlation between connectivity of pathways and conductivity, a/γ-LiAlO2 and Li2CO3 are investigated by the impedance spectrum as an example, and many experimental and theoretical studies are in process to indicate the relationship between property and structure. The BV method can calculate one material within a few minutes, providing an efficient way to lock onto targets from abundant data, and to investigate the struc- ture-property relationship systematically.展开更多
The systematic method for constructing Lewis representations is a method for representing chemical bonds between atoms in a molecule. It uses symbols to represent the valence electrons of the atoms involved in the bon...The systematic method for constructing Lewis representations is a method for representing chemical bonds between atoms in a molecule. It uses symbols to represent the valence electrons of the atoms involved in the bond. Using a number of rules in a defined order, it is often better suited to complicated cases than the Lewis representation of atoms. This method allows us to determine the formal charge and oxidation number of each atom in the edifice more efficiently than other methods.展开更多
Mine reclamation bonds are used in countries with mineral mining to ensure that reclamation of the mined area is completed. The United States, Canada, and Australia are countries with established mine reclamation bond...Mine reclamation bonds are used in countries with mineral mining to ensure that reclamation of the mined area is completed. The United States, Canada, and Australia are countries with established mine reclamation bond programs, with the United States coal system having been in place since 1977. China implemented a bonding system in 1998 and by 2013 all 31 provinces had established a system. An effective bonding system must be conditioned on fair and enforceable nationwide reclamation standard, stimulate companies to conduct reclamation by forming economic incentives rather than penalties that become a liability, and allow for full public participation. Based on these principles, this paper compares seven important factors for a successful reclamation bonding system： laws and regulations, administrative authority, bond types, bond size, calculation method, bond release, and public participation. The results show variation in policies and procedures for bonding among countries. Using principles and policies primarily from the United States, China should establish a national reclamation bonding system with legislation that forms a national authority to oversee and enforce reclamation standards and bond requirements. In addition, China can expand bond financial types and strategies, set the size of reclamation bonds at the level of a third-party reclamation cost, and set unified standards for calculation. Phased bond release should be established with specific reclamation criteria for each phase of release. Finally, bonding regulations should clearly identify opportunities for full public participation in the process.展开更多
The relationship between bond valence and bond covalency in RMn2O5 (R = La, Pr, Nd.Sm, Eu) has been investigated by a semiempirical method. This method is the generalization of thedielectric description theory of Phil...The relationship between bond valence and bond covalency in RMn2O5 (R = La, Pr, Nd.Sm, Eu) has been investigated by a semiempirical method. This method is the generalization of thedielectric description theory of Phillips. Van Vechten, Levine and Tanaka scheme. The resultsindicate that larger valences usually result in higher bond covalencies, in good agreement with thepoint that the excess charge in the bonding region is the origin of formation of bond covalency.Other factors, such as oxidation state of elements, only make a small contribution to bondcovalency.展开更多
基金This work was supported by the Natural Science Foundation of Shandong province (No.Y2002B06) and Science Research Foundation of Qingdao University of Science and Technology (No. 03Z08)
文摘The title compound [Ag(CH3CONHC(S)NH2)2](NO3) has been prepared by hydrothermal synthesis and characterized by single-crystal X-ray diffraction. It crystallizes in mo-noclinic, space group P21/c with Mr = 406.20 (C6H12Ag N5O5S2), a = 12.0680(6), b = 6.8056(5), c = 18.0173(1) ? b = 111.383(4), V = 1377.9(2) 3, Z = 4, Dc = 1.958 g/cm3 , F(000) = 808, = 1.789 mm-1, R = 0.0361 and wR = 0.1015. Of 4185 reflections ((2)max = 55.00?, 3147 were unique (Rint = 0.0174) and 2820 with I > 2(I) were used to solve the structure. The silver(I) atom adopts V-shape geometry with the AgS bond distance of 2.4271(7) and 2.7229(9) , respectively. Seven atoms of one acetylthiocarbamide ligand are coplanar, while only four atoms of another acetylthio-carbamide ligand are fairly planar. The [Ag(CH3CONHC(S)NH2)2]+ cation and nitrate anion NO3- are connected by hydrogen bonds to form a three dimensional hydrogen bonding network..
基金supported by the National Natural Science Foundation of China (Grant Nos. 11234013 and 51172274)the "Strategic Priority Research Program" of the Chinese Academy of Sciences (Grant No. XDA01010202)+1 种基金the National Basic Research Program of China (Grant No. 2012CB932900)the Project of Beijing Municipal Science & Technology Commission
文摘Inorganic solid electrolytes have distinguished advantages in terms of safety and stability, and are promising to substitute for conventional organic liquid electrolytes. However, low ionic conductivity of typical candidates is the key problem. As connective diffusion path is the prerequisite for high performance, we screen for possible solid electrolytes from the 2004 International Centre for Diffraction Data （ICDD） database by calculating conduction pathways using Bond Valence （BV） method. There are 109846 inorganic crystals in the 2004 ICDD database, and 5295 of them contain lithium. Except for those with toxic, radioactive, rare, or variable valence elements, 1380 materials are candidates for solid electrolytes. The rationality of the BV method is approved by comparing the existing solid electrolytes＇ conduction pathways we had calculated with those from ex- periments or first principle calculations. The implication for doping and substitution, two important ways to improve the conductivity, is also discussed. Among them LizCO3 is selected for a detailed comparison, and the pathway is reproduced well with that based on the density functional studies. To reveal the correlation between connectivity of pathways and conductivity, a/γ-LiAlO2 and Li2CO3 are investigated by the impedance spectrum as an example, and many experimental and theoretical studies are in process to indicate the relationship between property and structure. The BV method can calculate one material within a few minutes, providing an efficient way to lock onto targets from abundant data, and to investigate the struc- ture-property relationship systematically.
文摘The systematic method for constructing Lewis representations is a method for representing chemical bonds between atoms in a molecule. It uses symbols to represent the valence electrons of the atoms involved in the bond. Using a number of rules in a defined order, it is often better suited to complicated cases than the Lewis representation of atoms. This method allows us to determine the formal charge and oxidation number of each atom in the edifice more efficiently than other methods.
文摘Mine reclamation bonds are used in countries with mineral mining to ensure that reclamation of the mined area is completed. The United States, Canada, and Australia are countries with established mine reclamation bond programs, with the United States coal system having been in place since 1977. China implemented a bonding system in 1998 and by 2013 all 31 provinces had established a system. An effective bonding system must be conditioned on fair and enforceable nationwide reclamation standard, stimulate companies to conduct reclamation by forming economic incentives rather than penalties that become a liability, and allow for full public participation. Based on these principles, this paper compares seven important factors for a successful reclamation bonding system： laws and regulations, administrative authority, bond types, bond size, calculation method, bond release, and public participation. The results show variation in policies and procedures for bonding among countries. Using principles and policies primarily from the United States, China should establish a national reclamation bonding system with legislation that forms a national authority to oversee and enforce reclamation standards and bond requirements. In addition, China can expand bond financial types and strategies, set the size of reclamation bonds at the level of a third-party reclamation cost, and set unified standards for calculation. Phased bond release should be established with specific reclamation criteria for each phase of release. Finally, bonding regulations should clearly identify opportunities for full public participation in the process.
文摘The relationship between bond valence and bond covalency in RMn2O5 (R = La, Pr, Nd.Sm, Eu) has been investigated by a semiempirical method. This method is the generalization of thedielectric description theory of Phillips. Van Vechten, Levine and Tanaka scheme. The resultsindicate that larger valences usually result in higher bond covalencies, in good agreement with thepoint that the excess charge in the bonding region is the origin of formation of bond covalency.Other factors, such as oxidation state of elements, only make a small contribution to bondcovalency.
