金属键

Density Functional Theory Study on the Structures and Electronic Spectra of Quadruply Bonded Metal Compounds M2X4(PMe3)4 M=Cr, Mo, W; X=F, Cl, Br, I

篇名 金属四重键化合物M2×4(PME3)4 (M=Cr， Mo， W； X=F， Cl， Br， I)结构和电子光谱的密度泛函理论研究

Background and Objective: The basic structure of salicylaldehyde amino acid Schiff base compounds includes a C=N chemical bond.

背景与目的：水杨醛氨基酸Schiff碱基本结构中含C＝N键，当基与金属离子配位后生物活性增强，表现出一定的抗癌、抑菌等活性。

Depression mechanism of sodium silicate on Titanaugite was that silicon acid colloidal particles with negative charge were formed by oxidate polymerization, adsorpted on the mineral's surface, provided the minerals with hydrophilicity, and consequently, Titanaugite was depressed.

水玻璃对钛辉石的抑制作用主要表现在：在弱酸性介质中，通过氧联反应聚合成的、带负电荷的硅酸胶粒在矿物表面吸附后，使矿物表面亲水，阻止了有机捕收剂羟肟酸在钛辉石表面与金属离子键合。

On the basis of the summarization of MCM-Cs main features and its assembly and packaging technologies, the paper puts stress on relatively deepgoing studies in practically advanced MCM-C assembly process technologies as gold ball wire bonding, IC chip gold ball stud bump making, IC flip chip bonding and underfilling, in high reliability MCM-C packaging process technologies as integral LTCC substrate packaging, hermetically metal sealing, and also in the basic technological process of MCM-C assembly and packaging. Later on, it presents the effectively engineering development of two high level actual module products--a high-density monolithic processor system MCM-C , a high-speed data collecting and processing system MCM-C. Lastly, it briefly introduces various common methods of quality inspection and reliability test of MCM-C assembly and packaging in engineering practice.

论文在综述MCM-C的主要特点及其组装封装技术的基础上，重点对金丝球引线键合、IC芯片金球凸点制作、IC芯片倒装焊与下填充等实用先进MCM-C组装工艺技术和LTCC基板与外壳及PGA引线的一体化封装、气密性金属封装等高可靠MCM-C封装工艺技术以及MCM-C组装封装基本工艺流程展开了较深入的研究，有效完成了高密度单片机系统MCM-C和高速数据采集控制系统MCM-C等两种高水平实际产品的工程化研制工作，扼要介绍了工程实践中MCM-C组装封装工艺常用的质量检验方法和可靠性试验方法。

It was found that the central metal ion is located at the symmetric center of the molecule. Four oxygen atoms from two H2O molecules and two 〔C6H4(CO2)2〕2- groups are coordinated with copper ion to form a similar planar square coordination configuration. There is one only unidentate coordination bond between O(1) in 〔C6H4(CO2)2〕2- and Cu2+.

结构分析发现，中心金属离子位于分子的对称中心位置，铜离子与来自2个水分子和2个邻苯二甲酸根中的4个氧原子形成近似正方形平面配位，邻苯二甲酸根是以1个O(1)与Cu2+离子形成单齿配体，O(2)和Cu2+之间没有形成配位键。

Open Layer window (F7), select chrono metal ring and make New Layer beneath it.

打开层窗口（F7键），选择时辰金属环，使底下的新层。

The main reason of complex with greater nonlinear refractive index is that the complex has larger conjugated delocalized system and there are electrons shifting between ligand and metal atom.

选择具有π键的配体与金属离子合成为配合物，使其非线性效应明显增强，这对合成性能更好的非线性材料有一定的参考价值。

Better agreement between metallic Pd~n-CO clusters and CO/Pd chemisorption systems demonstrates that the "Metallic State Principle" overweighs the "Lowest Spin State Principle".

总的计算结果表明，依据金属态原则，其结果可以更好地符合CO/Pd吸附体系的实验数据，并认为CO/Pd吸附过程的成键作用主要是CO(5σ)→Pd(5sp)与Pd(5sp)→CO(2π^*)的σ/π授受作用。

The ligands donate the lone pair electrons to the central metal to form the covalent bondings, called coordination bondings.

配体提供原子对与金属原子形成的共价键称为配位键。

The lower energy is because that the chemical bond between O〓 and M〓 has not formed completely, which cause by the higher covalency of Eu〓-O〓 bond in amorphous state. And the larger half width is caused by the disorder of sites.

这是由于在非晶态状态下金属氧键尚未完全形成，从而导致Eu〓-O〓的共价性较高，因此电荷迁移带处于较低的能量位置；而格位的无序性导致其光谱变宽。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。