In Chemistry, What Is the Periodic Law?

Inorganic chemistry is the study of chemistry of inorganic compounds, and is an important branch of chemistry. In general, inorganic compounds are opposed to organic compounds, and refer to most compounds that do not have a CH bond, but carbon oxides, carbon sulfides, cyanides, thiocyanates, carbonic acid and carbonates, carborane, and carbonyl metals are all inorganic. The scope of chemical research ( actually, "substances studied by inorganic chemistry" are defined as "inorganic substances" ) ^[1-2] . However, the two boundaries are not strict, and there is a large overlap between them. Organometallic chemistry is an example.

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Inorganic chemistry is a science that conducts experimental research and theoretical interpretation of the properties of all elements and their compounds and their reactions in addition to hydrocarbons and their derivatives. It is one of the earliest branches of chemistry.

In the past, inorganic substances were considered to be inanimate substances, such as rocks, soil, minerals, and water; while organic substances were produced by living animals and plants, such as proteins, oils, starches, cellulose, and urea. In 1828, German chemist Weiler made urea from inorganic ammonium cyanate, thereby breaking the superstition that organic matter can only be generated by vitality, and it was clear that both types of substances were combined by chemical force. At present, these two types of substances are divided according to different research fields (so it is often the case that some substances containing carbon chains and organic ligands are classified as inorganic substances ). There are other detailed classifications of chemistry. ^[1-2]

Primitive humans were able to discern the nature of inorganic substances in nature and use them. Later, they accidentally discovered that natural substances can change into new substances with different properties, and then imitated them. This was the beginning of ancient chemical technology.

For example, at least 6000 BC, Chinese primitive people knew how to make clay pottery, and gradually developed into colored pottery, white pottery, glazed pottery and porcelain. Around 5000 BC, humans found that natural copper is tough and difficult to break when used as an appliance. Later, it was observed that copper ores such as malachite (basic copper carbonate) contacted with burning charcoal to be decomposed into copper oxide, and then reduced to metallic copper. After repeated observation and experiments, finally mastered the reduction of copper ore with charcoal Copper smelting technology. Later, he successively mastered the technologies of tin smelting, zinc smelting and nickel smelting. In the Spring and Autumn and Warring States Period, China mastered the technology of iron smelting from iron ore and steel making from iron. In the 2nd century BC, China discovered that iron can react with copper compound solutions to produce copper. This reaction became one of the later methods of producing copper. This method Also called "wet copper smelting."

In terms of compounds, in the Shang Dynasty in the 17th century BC, salt (sodium chloride) was a condiment, and bitter salt (magnesium sulfate) had a bitter taste. In the fifth century BC glazed (polysilicate) vessels were available. In the seventh century, China made of flame nitrate (potassium nitrate), sulfur, and charcoal.

At the beginning of the establishment of inorganic chemistry, its knowledge content had four categories, namely facts, concepts, laws and doctrines.

The materials obtained by directly observing things with the senses are called facts; the specific characteristics of things are analyzed, compared, synthesized, and summarized to obtain concepts, such as elements, compounds, compounds, compounds, oxidation, reduction, atoms, etc. are the first of inorganic chemistry Clear concepts; combining corresponding concepts to summarize the same facts becomes a law, for example, different elements are synthesized into various compounds, and their quantitative relationships are summarized to derive laws such as mass conservation, constant ratio, and multiple ratio; establish new ones The concept is to explain the related laws, and the new concept has been proved to be correct through experiments, namely the theory of accomplishment. E.g,

Chen Rong Liang Wenping ^[3]

(Department of Chemical Science, National Natural Science Foundation of China, Beijing 100085)

In recent years, with the support of the National Natural Science Foundation and other basic projects, China's inorganic chemistry has made outstanding progress in basic research, with a lot of results, and the work of a group of young and middle-aged experts has stood out. Some experts have made outstanding achievements in the transformation of scientific research results and industrialization; some experts have worked in the international high-level professional magazines Science, Accounts of Chemical Reserch, Angew.Chem.Int.ed., J. Am. Chem. Soc. Published a number of influential scientific papers. Taking the well-known chemistry journals Angew. Chem. Int. Ed. And J. Am. Chem. Soc. As examples, according to incomplete statistics, mainland scholars have published a total of 44 papers on Angew. Chem. Int. Ed. Among them, 18 were published by experts in the field of inorganic chemistry, accounting for 41%. Especially in the past two years, mainland scholars have published a total of 30 papers on Angew. Chem. Int. Ed., And experts in the field of inorganic chemistry have published 16 papers, accounting for 53%, a rapid growth; in the past 10 years, mainland scholars in J. Am. 53 papers published on Chem. Soc., 11 papers published by inorganic chemistry scholars, accounting for 20%; experts in organic chemistry, 8 papers published on Angew. Chem. Int. Ed .; J. Am. Chem. He has published 14 papers on Soc. And has shown good development momentum. We believe that with the support of the National Natural Science Foundation of China, the discipline of chemistry can continue to make breakthroughs in basic research, open up new fields, and carry out internationally leading original research work. Inorganic chemistry has achieved remarkable results in the following areas:

1. Qian Yitai and Xie Yi research group of University of Science and Technology of China designed and realized new inorganic chemical reactions in organic systems based on hydrothermal synthesis work, and prepared a series of non-oxide nanomaterials at relatively low temperature. The principle of solvothermal synthesis is similar to that of hydrothermal synthesis. Organic solvents are used instead of water to achieve chemical reactions in a sealed system. Their work on the preparation of nano-GaN by reacting GaCl3 and Li3N at 280 ° C in benzene was published in Science, and the reviewers evaluated it as "the article reports two exciting research results: benzene heat prepared at very low temperature Crystalline GaN; metastable cubic rock salt facies previously observed only under ultra-high pressure was observed .... "The article has been cited 60 times by Science and other publications. InAs was prepared by solvothermal co-reduction in toluene, and the article was published on J. Am. Chem. Soc .; in the presence of KBH4, nano-InAs was prepared by reacting simple As with InCl3 in low toxicity. The article was published in Chem. Mater. Above; CCl4 and metal Na undergo a similar Wurtz reaction to make diamonds at 700 ° C. This work was published in Science shortly after being evaluated as "straw to gold" by the US "Chemistry and Engineering News"; one-dimensional synthesis by solvothermal CdE (E = S, Se, Te), the article was published on Chem. Mater .; the work of reducing one-dimensional SiC nanorods at 400 ° C with metal Na reduced CCl4 and SiCl4 was published on Appl. Phys. Lett., The reviewers considered this to be a "new and very interesting synthesis method, ... which will promote further work in this field"; solvothermal synthesis of polymetallic chalcogenide nanomaterials: such as AgMS2 and CuMS2 (M = Ga, In) 's article was published in Chem. Commum. And Inorg. Chem., Respectively; the solvent preparation of some chalcogenide nanomaterials was successfully reduced to room temperature, and one-dimensional selenide work was published in J. Am. Chem. Soc. And Adv. Mater .; preparation of indefinite compounds and Identification of stable phases: Co9S8 the like as a non-stoichiometric compound solvothermal synthesis published on Inorg Chem, rock salt-type GaN metastable phase of a high-resolution electron microscope to identify the work published in Phys Lett Appl......

2. The research team of Feng Shouhua and Xu Ruren of Jilin University successfully applied hydrothermal synthesis technology to successfully synthesize M (4,4'-bipy) 2 (VO2) 2 (HPO4) 4 (M = Co; Ni). In these two compounds, PO4 tetrahedron and VO4N triangular double cones form a novel V / P / O inorganic spiral chain by alternating arrangement of common oxygen atoms. Coexistence of left-handed and right-handed V / P / O helix chains in the structure. These left-handed and right-handed spiral chains are strictly alternated and are connected by the M (4,4'-bipy) 2 structural unit to form an open three-dimensional structure. The formation of the inorganic spiral chain is attributed to the pulling force generated by the coordination of two bipyridine rigid molecules on the M (4,4'-bipy) 2 structural unit with vanadium atoms on two adjacent spiral chains. The results were published in Angew. Chem. Int. Ed. 2000, Vol. 39, No. 13,2325-2327.

In view of the systematic and innovative research work in the international frontier field of inorganic hydrothermal synthesis, Professor Feng Shouhua and Academician Xu Ruren of the State Key Laboratory of Inorganic Synthesis and Preparative Chemistry of Jilin University were invited to the American Chemical Society's Accounts of Chemical Reserch) write a review paper. The review is entitled "New Materials in Hydrothermal Synthesis" (Acc. Chem. Res., 34 (3), 239? / FONT> 247, 2001). This article systematically summarizes the research results of hydrothermal synthesis chemistry of new materials from the following seven aspects: microporous crystals; ionic conductors; composite oxides and composite fluorides; low-dimensional aluminum phosphate; inorganic / organic hybrid materials; special Aggregate materials; materials, life, environmental and social issues.

3. Xiong Rengen and You Xiaozeng of Nanjing University designed and synthesized a multi-dimensional structure of inorganic-organic hybrids with chiral and catalytic functions in the study of the assembly and chiral resolution of optically active zeolites. They modified the optically active zeolites. Natural organic drug (quinine), using it as a ligand to self-assemble with metal ions constitutes an optical resolution (or selective inclusion of S-configuration) racemic 2-butanol and 3-methyl-2 -Butanol, a three-dimensional porous zeolite with a resolution of more than 98%. In the successful design of this class of zeolites, we mainly considered the following factors: negative monovalent anion ligands (excluding the possibility of external anions occupying voids); ligands have a large number of organic parts to enhance hydrophobicity; also have affinity The water group, N, OH and other groups coexist in one ligand so that the ligand is amphoteric; multiple chiral centers (4). This is currently the first optically active zeolite that can be resolved. This work is considered to be very important and meaningful work, published in Angew. Chem. Int. Ed., (2001, 40, 4422-4425) And was selected as Hot Paper.

4. Hong Maochun, Wu Xintao, etc. of the Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, have published 30 papers on nanomaterials and inorganic polymers. They have been published in high-level international journals such as Angew. Chem. Int. Ed., J. Am. Chem. Soc., Chem. Eur. J., Chem. Comm., Inorg. Chem., Has attracted wide attention from colleagues at home and abroad.

They considered the synergy and structural regulation of organic bridging ligands and metal ions in the synthesis, structure, and performance of nanometer-sized metallomolecular cages. They designed and synthesized a tridentate containing organic sulfur and nitrogen. The bridged ligand tpst, in which the pyridine ring and the central spacer are connected by a flexible thioether. Through the self-assembly reaction of the tpst ligand with a bivalent nickel, palladium or platinum ion, we successfully constructed a cubic metal with Oh symmetry -Organic cage [Ni6 (tpst) 8Cl12], the volume of which is more than 1000? 3, which can hold a variety of ions and solvent molecules at the same time. The cage is stable at 100 ° C and has 12 large variable windows that allow small molecules to enter and exit the cage. This is the metal-organic cage with the largest single crystal structure (J. Am. Chem. Soc. 2000, 122, 4819-4820).

The synthesis, structure and properties of a new type of metal-organic macroporous zeotype with large pores were studied. Research in this area is mainly focused on the synthesis of suitable organic ligands and the design of composite polymers with appropriate pore size and shape. They gradually assembled the tpst ligand and monovalent metal ions to make a one-dimensional polymer [Ag7 (tpst) 4 (ClO4) 2 (NO3) 5] n] with a nanometer tube, which can be simultaneously in the tube Holds ions and small molecules. This is currently the only one-dimensional polymer with metal-organic nanotubes.

They also successfully constructed a new type of molecular sieve [{Zn4 (OH) 2 (bdc) 3} · 4 (dmso) 2H2O] n) with nano-scale pores, in which the size of the pores is nearly one nanometer. The metal of the skeleton may be a metal cluster having catalytic activity. Multi-dentate carboxylic acid large ligands were reacted with rare earth metals and transition metal ions to make a variety of one-dimensional, two-dimensional and three-dimensional polymers containing rare earth metals and transition metals and having large pores, [Gd2Ag2 (pydc) 4 ( H2O) 4] n [{Gd2Cu3 (pydc) 6 (H2O) 12} .4H2O] n, [{Gd4Cu2 (pydc) 8 (H2O) 12} .4H2O] n, [{Gd2Zn3 (pydc) 6 (H2O) 12 } .4H2O] n, [{Gd4Zn2 (pydc) 8.

Synthesis and structural study of metal nanowires and metal-organic nanoplates. Some metal nanowires, metal-nonmetal nanowires and metal organic nanoplates were designed and synthesized. Structural chemical research methods were used to study their self-assembly rules, space structures, electronic structures, and their physical and chemical properties. The relationship between performance.

5. Takamatsu's research group at Peking University has achieved outstanding results in the research of magnetic molecular materials. Special magnetic relaxation phenomenon dependent on external magnetic field. K3 [M (CN) 6] (M = FeIII, CoIII), bpym (2,2'-bipyrimidine), and Nd (NO3) 3 were slowly diffused in a 1: 1: 1 molar ratio in an aqueous solution to synthesize the first For example, a cyanide bridged 4f-3d two-dimensional coordination polymer [NdM (bpym) (H2O) 4 (CN) 6] × 3H2O, a large hexagonal ring formed by 24 atoms is connected by vertices and edges, respectively, to construct Into a unique two-dimensional topology. By comparing the magnetic properties of two compounds with the same structure, it was confirmed that there is a weak ferromagnetic interaction between NdIII-FeIII. Although long-range magnetic order is not observed above 2K, and the temperature-changing AC susceptibility also exhibits normal paramagnetic behavior under zero external field, AC susceptibility exhibits slow magnetic relaxation and Paramagnets are similar to spin glasses. A preliminary explanation was given using the geometrical spin frustration of the system (Angew. Chem.-Int. Ed., 40 (2), 434-437, 2001).

Metal clusters are supramolecular assemblies of structural units. The pH of the solution was adjusted to about 6.5 by mixing an aqueous solution of rare earth salt Dy (ClO4) 3 and aspartic acid. A three-dimensional open-framework coordination polymer was synthesized with a pore size of 11.78A. As a result of replacing monobasic aminocarboxylic acid with a dicarboxylic acid aspartic acid, the amino acid rare earth complex formed at physiological pH was assembled from a discrete tetranuclear cubic alkane structure into a three-dimensional hypercubane (Angew. Chem. -Int. Edit., 39 (20), 3644-6, 2000).

Cyanide bridged three-dimensional ferromagnet. A cyanide bridge was synthesized by reacting a dicyanide complex [RuIII (acac) 2 (CN) 2]-stabilized with 4d metal ion Ru (III) as a "building block" with 3d metal ion Mn (II). 3D coordinated polymer with a diamond-like structure. Magnetic studies have shown that Ru-Mn is ferromagnetic and exhibits long-range ferromagnetic ordering below 3.6 K. This is the first example of a molecular ferromagnet containing Ru (III).

Slowly diffuse Cu (en) (H2O) 2SO4 aqueous solution to K3 [Cr (CN) 6] in water-ethanol solution to obtain a three-dimensional coordination polymer with novel structure [Cu (EtOH) 2] [] Cu (en)] 2 [Cr (CN) 6] 2. Magnetic studies have shown that Cr-Cu exhibits ferromagnetic interactions and exhibits long-range ferromagnetic ordering below 57 K. This is the first Cr-Cu three-dimensional molecular magnet characterized by structure and magnetic properties (Angew. Chem.-Int. Edit., 40 (16), 3031-3, 2001; J. Am. Chem. Soc., 123, 11809 -10, 2001).

6. Li Yadong's research group at Tsinghua University has made outstanding progress in the preparation and assembly of new one-dimensional nanostructures. Li Yadong's group discovered for the first time a new type of single-crystal multi-walled metal nanotubes formed from metal bismuth with quasi-layered structure characteristics. The relevant research results are in the Journal of the American Chemical Society (J. Am. Chem. Soc. 123 ( 40), 9904 ~ 9905, 2001). This is the first single crystal nanotube made of metal in the world. The discovery of bismuth nanotubes has provided new objects and topics for the formation mechanism and application research of inorganic nanotubes.

They also designed the use of synthetic organic-inorganic layered structures as precursors to synthesize metal tungsten single crystal nanowires and high-quality WS2 nanotubes. With the help of small-angle X-ray diffraction and high-resolution electron microscopy, the detailed study of The layered curling mechanism of precursors to nanotubes provides new methods and ideas for the synthesis of one-dimensional nanowires and nanotubes. This work was published in German Applied Chemistry (Angew. Chem. Int. Ed. 41 (2), 333 ~ 335, 2002) and Journal of the American Chemical Society (J. Am. Chem. Soc. 124 (7), 1411 ~ 1416, 2002).

7. The research group of Northeast Normal University Wang Enbo is leading in the study of polymetallic oxygen clusters. Great achievements have been made in the design and synthesis of polymetallic oxygen cluster crystals and functional materials of polymetallic oxygen clusters. Wang Enbo's group has published many papers in high-end international journals, such as German Applied Chemistry and Journal of the American Chemical Society, which have attracted widespread attention.

One-dimensional oxide nanowires, ribbons, and tubes have attracted much attention due to their wide application scenarios. Li Yadong and others successfully synthesized high-quality a and b manganese dioxide nanowires and nanorods under mild conditions through the liquid phase reaction pathway, and realized the regulation of product phase formation. In addition, they also synthesized single-crystal MoO3 nanoribbons and titanate nanotubes. Part of this work has been published in the Journal of the American Chemical Society (J. Am. Chem. Soc. 124 (12), 2880 ~ 2881, 2002) and other journals.

The outstanding progress that inorganic chemistry has made in recent years is mainly reflected in solid material chemistry and coordination chemistry, which has kept pace with international development to some extent. From the perspective of traditional inorganic chemistry, the research on bioinorganic chemistry and radiochemistry is relatively lagging behind. With the joint support of the Policy Bureau of the National Natural Science Foundation of China, the Ministry of Chemistry, and the Ministry of Chemistry of the Chinese Academy of Sciences, a seminar on the strategy for the development of bioinorganic chemistry was held in Shenzhen on March 5-7, 2002. The meeting analyzed the strong driving forces and trends of the development of bio-inorganic chemistry at home and abroad and the current cross-development of life science and chemical science. China's bioinorganic chemistry began to develop in the 1980s, when it was about 10 years behind the world. With the support of the National Natural Science Foundation of China for more than ten years, and the efforts of all researchers engaged in bioinorganic chemistry, the research on bioinorganic chemistry has jumped three steps in 10 years, and the research objects have risen from small biological ligands to biological large molecules. Molecules; from the study of isolated biological macromolecules to the study of biological systems; in recent years, research on inorganic chemistry at the cell level has begun, and the level of research has increased year by year. China has a relatively fixed research direction in the interactions between metal complexes and biological macromolecules, the structure and function of metal proteins, the chemical basis of the biological effects of metal ions, and inorganic medicinal chemistry and biomineralization. The research team is becoming younger and younger. . However, there is still a certain gap between the overall level of China's bioinorganic chemistry and the international level. The reason is that research funding is insufficient and the research cycle is long. The most prominent problem is the lack of outstanding young research talents. Radiochemical research also shows the above characteristics, the most important of which is to support young research talents to stand out.