18 electron rule

简明释义

18 电子则

英英释义

例句

1.A complex that adheres to the 18 electron rule is often considered to be electronically saturated.

遵循18电子规则的配合物通常被认为是电子饱和的。

2.The 18 electron rule helps in understanding why certain metal complexes are more reactive than others.

通过18电子规则可以理解为什么某些金属配合物比其他配合物更具反应性。

3.When synthesizing new metal-organic frameworks, chemists often refer to the 18 electron rule to predict the electronic structure.

在合成新的金属有机框架时，化学家们经常参考18电子规则来预测电子结构。

4.The stability of many transition metal complexes can be explained using the 18 electron rule, which states that a stable complex typically has 18 valence electrons.

许多过渡金属配合物的稳定性可以用18电子规则来解释，该规则指出，稳定的配合物通常具有18个价电子。

5.In organometallic chemistry, the application of the 18 electron rule is crucial for designing catalysts.

在有机金属化学中，应用18电子规则对设计催化剂至关重要。

作文

The 18 electron rule is a fundamental principle in the field of coordination chemistry and organometallic chemistry. This rule provides a guideline for predicting the stability and reactivity of transition metal complexes. According to the 18 electron rule, a stable complex will typically have a total of 18 valence electrons, which corresponds to the electron configuration of noble gases. This concept is particularly useful when studying the bonding and electronic structure of metal complexes. Transition metals have varying numbers of d-electrons, and when they form complexes with ligands, these ligands donate electrons to the metal center. The total number of electrons from both the metal and the ligands should ideally add up to 18 for the complex to be considered stable. For example, a metal ion with 6 d-electrons can form stable complexes with ligands that donate 12 electrons, reaching the total of 18. The significance of the 18 electron rule extends beyond mere electron counting; it also helps chemists understand the geometric arrangements and possible oxidation states of metal complexes. Complexes that adhere to this rule often exhibit low reactivity, as they are in a stable electronic configuration. Conversely, complexes that do not meet the 18 electron rule may be more reactive, indicating that they are seeking additional electrons to achieve stability.However, it is crucial to note that while the 18 electron rule serves as a useful guideline, there are exceptions. Some metal complexes can be stable with fewer or more than 18 electrons due to factors such as sterics, electronic effects, and the nature of the ligands involved. For instance, certain low-coordinate complexes may only have 16 electrons yet remain stable due to strong metal-ligand interactions. Additionally, the 18 electron rule has implications in catalysis. Many catalytic processes involve transition metal complexes, and understanding their electron count can provide insight into their catalytic activity. For example, in homogeneous catalysis, the efficiency of a catalyst can often be linked to whether it adheres to the 18 electron rule. Catalysts that maintain this electron count tend to exhibit better performance due to their stable electronic configurations. In summary, the 18 electron rule is an essential tool for chemists working with transition metal complexes. It aids in predicting the stability, reactivity, and geometry of these complexes. While there are exceptions to the rule, its application provides a foundational understanding of the electronic principles governing coordination chemistry. As research continues in this field, the 18 electron rule remains a vital concept that guides scientists in the exploration of new materials and reactions.

“18电子规则”是配位化学和有机金属化学领域的一个基本原则。这个规则为预测过渡金属配合物的稳定性和反应性提供了指导。根据18电子规则，一个稳定的配合物通常会有18个价电子，这对应于惰性气体的电子配置。这个概念在研究金属配合物的键合和电子结构时尤其有用。过渡金属具有不同数量的d电子，当它们与配体形成配合物时，这些配体会向金属中心捐赠电子。金属和配体提供的电子总数理想情况下应该加起来达到18，以使配合物被认为是稳定的。例如，一个具有6个d电子的金属离子可以与捐赠12个电子的配体形成稳定的配合物，达到18的总数。18电子规则的重要性不仅仅在于电子计数；它还帮助化学家理解金属配合物的几何排列和可能的氧化态。遵循这一规则的配合物通常表现出较低的反应性，因为它们处于稳定的电子配置中。相反，不符合18电子规则的配合物可能更具反应性，这表明它们正在寻求额外的电子以实现稳定。然而，必须注意的是，尽管18电子规则作为有用的指导方针，但也存在例外。一些金属配合物即使电子数少于或多于18仍然可以稳定，原因包括空间效应、电子效应和配体的性质。例如，某些低配位的配合物可能只有16个电子，但由于金属-配体间的强相互作用而保持稳定。此外，18电子规则在催化中的应用也很重要。许多催化过程涉及过渡金属配合物，理解它们的电子计数可以提供有关其催化活性的见解。例如，在均相催化中，催化剂的效率往往与其是否遵循18电子规则有关。保持该电子计数的催化剂由于其稳定的电子配置，往往表现出更好的性能。总之，18电子规则是化学家在研究过渡金属配合物时的重要工具。它有助于预测这些配合物的稳定性、反应性和几何形状。尽管存在例外，但这一规则的应用为理解配位化学的电子原理提供了基础。随着该领域研究的持续进行，18电子规则仍然是指导科学家探索新材料和反应的关键概念。