Significant progress has been made in the synthesis of transition metal compounds. Transition metal compounds have become a research hotspot in the field of inorganic solid chemistry because of their unique force, heat, light, electricity, magnetic properties, and many synergistic effects. The key project of the National Natural Science Foundation of China was presided over by Meng Jian, a researcher from the State Key Laboratory of Rare Earth Resources Utilization of Changchun Institute of Applied Chemistry, and a research team composed of Professor Xing Xianran from Beijing University of Science and Technology, and Wu Zhijian and Cao Xueqiang from Changchun Yinghua Institute "Synthesis of transition metal compounds and research on their special properties" have recently been appraised by experts organized by the National Natural Science Foundation of China. Experts believe that the research results obtained by the project have important academic significance and wide practical application value, reaching the advanced level of similar international research. 1. In view of the relationship between the structure of transition metal compounds, the formation of chemical bonds and the electrical and magnetic properties, the structural design of the compounds was carried out, and the theoretical simulation of the structure-activity relationship was carried out to try to clarify the relationship between the crystal structure of the compounds and the physical properties. The electrical and magnetic properties of YBaMn2O5 were studied, and it was found that the magnetic coupling of such compounds changed from G-type antiferromagnetic to A-type antiferromagnetic with the change of Mn-O-Mn angle. The theoretical calculation results support both The experimental results also verified Goodenough's magnetic coupling theory. The thermodynamic stability of a new compound CaCu3Fe4O12 was successfully predicted, and it has a ferrimagnetic semi-metallic structure, which is very likely to become a new type of spin electronic material. Soon after our article was published, the research team of Professor Y. Shimakawa of Kyoto University in Japan successfully synthesized the compound, which fully proved the reliability and prospectiveness of theoretical research. 2. Starting from the structural design, the relationship between the structural distortion and physical properties of the compound was studied, the mechanism of ion and electron conduction in the compound was proposed, and an oxygen ion conductor with good performance under low and medium temperature was designed and synthesized. A complete set of electrical property test system was designed and developed by ourselves, which can automatically control the conductivity and Seebeck coefficient of the measured materials. The test range of temperature and oxygen partial pressure is wide (1 ~ 10-17Pa, room temperature ~ 1000 ℃), which can simulate the atmosphere of any oxygen partial pressure; new solid oxide electrolytes La2Mo2O9, La3MMo2O12 and double perovskite structure oxidation are designed and synthesized It was found that the oxygen ion conductivity in the middle temperature region is higher than that of the traditional solid electrolyte of fluorite and perovskite structure. It was found that the interaction of the d orbitals of the Mo ions can form a direct overlap of the t2g orbits. It can be considered that the electrons of the Mo ions jump to the neighboring Mo ions through the σ bond or the π bond, thereby generating electron conduction. Further perfected the ion and electron conduction mechanism. 3. A series of lead-based titanate ceramics were studied, and the structural refinement of the compound's full-spectrum fitting was carried out by the Rietveld method. The ordered-disordered model was used to solve the ordered-no Order problem, it was found that the doping of transition metal ions can well adjust the thermal expansion properties of the compound, and a new material with near zero expansion was found. Through design synthesis and structural distortion methods, the lead-based titanate ceramic (1-xy) PbTiO3-xBiFeO3-yBi (Ti1 / 2Zn1 / 2) O3 was studied, and their structure was refined through Rietveld. The order-disorder model solves the order-disorder problem at the B site; a PbTiO3-0.1BiFeO3-0.3Bi (Zn1 / 2Fe1 / 2) O3-based compound with zero expansion at -140? 700 ℃ was found. The synthesis, crystal structure, thermal expansion of the rare earth doped lead-based titanate series compounds, the corresponding solid solution limit, the non-stoichiometry of the compound, the thermodynamic stability of the solid solution compound, the solid solution compound (nanoparticles) ) The relationship between morphology and solid solubility, etc. It was found that the negative thermal expansion material solid electrolyte Zr1-xYbxW2O8 is an oxygen ion conductor at 300-700 ° C; adding Y plus impurities increases the vacancy concentration and improves the ionic conductivity. A negative thermal expansion composite material ZrW2O8 / Al2O3 ceramic with adjustable thermal expansion coefficient and good ceramic mechanical properties was prepared. For the first time, the negative thermal expansion characteristics of lead-based titanate were enhanced, and it was found that the TEC material can be adjusted to (near) zero expansion. The above research results have important academic significance and wide practical application value, and have reached the advanced level of similar international research.

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