主要差异离子(main difference ionic) vs. 共价的(covalent)

债券可分为两大类；一级债券和次级债券。主键是将原子固定在分子中的化学键，而二次键则是将分子结合在一起的力。主要有三种类型的键，即离子键、共价键和金属键。二次键包括色散键、偶极键和氢键。一次键具有较高的键能，与二次力相比，它更稳定。离子共价键与金属键的主要区别在于它们的形成；当一个原子向另一个原子提供电子时，离子键形成，而当两个原子在金属晶格**享可变数量的电子时，两个原子共享价电子和金属键时形成共价键。

本文探讨，

1.什么是离子键？–定义、形成、性质

2.什么是共价键？–定义、形成、性质

3.什么是金属键？–定义、形成、性质

4. What is the difference between Ionic Covalent and Metallic Bonds?

什么是离子键(ionic bonds)？

Certain atoms tend to donate or receive electr*** in order to become more stable by completely occupying their outermost orbit. Atoms with very few electr*** in their outermost shell tend to donate the electr*** and become positively charged i***, while atoms with more electr*** in their outermost orbit have a tendency to receive electr*** and become positively charged i***. When these i*** are brought together, the attraction forces are occurred due to opposite charges of i***. These forces are called ionic bonds. These stable bonds are also called electrostatic bonds. Solids bonded with ionic bonds have crystalline structures and low electrical conductivity, which is due to lack of free moving electr***. Bonds usually occur between metal and non-metal that are having a large difference in electronegativity. Examples of ionically bonded materials include LiF, NaCl, BeO, CaF2 etc.

什么是共价键(covalent bonds)？

Covalent bonds are formed when two atoms share their valence electr***. The two atoms have a **all difference in electronegativity. Covalent bonds occur between same atoms or different types of atoms. For example, fluorine needs one electron to complete its outer shell, thus, one electron is shared by another fluorine atom by making a covalent bond resulting F2 molecule. Covalently bonded materials are found in all three states; i.e., solid, liquid and gas. Examples of covalently bonded material include hydrogen gas, nitrogen gas, water molecules, diamond, silica etc.  

什么是金属键(metallic bonds)？

In a metal lattice, valence electr*** are loosely attached by the nuclei of metal atoms. Thus, valence electr*** require very low energy to release themselves from nuclei. Once these electr*** detach, metal atoms become positively charged i***. These positively charged i*** are surrounded by a large number of negatively charged, free moving electr*** called an electron cloud. Electrostatic forces are formed due to the attracti*** between the electron cloud and i***. These forces are called metallic bonds. In metallic bonds, almost every atom in the metal lattice shares electr***; so there is no way to determine which atom shares which electron. Because of this reason, electr*** in metallic bonds are referred to as delocalized electr***. Due to the free moving electr***, metals are known for good electricity conductors. Examples of metals with metallic bonds include iron, copper, gold, silver, nickel etc.

离子共价(ionic covalent)和金属键(metallic bonds)的区别

定义

离子键：离子键是在负离子和正离子之间产生的静电。

共价键：共价键是当两个元素共享一个价电子以获得中性气体的电子构型时形成的键。

金属键：金属键是带负电的****电子和带正电的金属离子之间的作用力。

键能

离子键：键能高于金属键。

共价键：键能高于金属键。

金属键：键能低于其他主键。

形成

离子键：当一个原子向另一个原子提供电子时形成的离子键。

共价键：两个原子共用价电子时形成共价键。

金属键：当一个金属晶格中有可变数量的原子共享可变数量的电子时，金属键就形成了。

导电性

离子键：离子键的导电性很低。

共价键：共价键的导电率很低。

金属键：金属键具有很高的导电性和导热性。

熔点和沸点

离子键：离子键具有较高的熔点和沸点。

共价键：共价键具有较低的熔点和沸点。

金属键：金属键具有高熔点和沸点。

物理状态

离子键：离子键只存在于固态。

共价键：共价键以固体、液体和气体的形式存在。

金属键：金属键只以固体的形式存在。

债券性质

离子键：这种键是非定向的。

共价键：键是定向的。

金属键：键是非定向的。

硬度

离子键：由于晶体结构，离子键很硬。

共价键：除了金刚石、硅和碳，共价键不是很硬。

金属键：金属键不是很硬。

延展性

离子键：具有离子键的材料不可延展。

共价键：具有共价键的材料是不可延展的。

金属键：具有金属键的材料具有延展性。

延展性

离子键：具有离子键的材料不具有延展性。

共价键：具有共价键的材料不具有延展性。

金属键：具有金属键的材料具有延展性。

示例

离子键：例如LiF、NaCl、BeO、CaF2等。

共价键：例如氢气、氮气、水分子、金刚石、二氧化硅等。

金属键：例如铁、金、镍、铜、银、铅等。

参考文献：

Cracolice, Mark. Basics of Introductory Chemistry with Math Review. 第2版，n.p.：cengage learning，2009，印刷版。

Duke, Catherine Venessa. A., and Craig Denver Williams. Chemistry for Environmental and Earth Sciences. n、 页：华润出版社，2007年出版。

Garg, S. K. Comprehensive Workshop Technology. n、 p.：laxmi出版物，2009年。印刷。

Image Courtesy:

“Ionic Bonds” By BruceBlaus – Own work (CC BY-SA 4.0)通过Comm*** Wikimedia

“Covalent Bonds” By BruceBlaus – Own work (CC BY-SA 4.0)通过Comm*** Wikimedia

“Metallic bonding” By Muskid – Own work (CC BY-SA 3.0) 通过Comm*** Wikimedia