The key difference between electrovalent and covalent bond is that electrovalent bond occurs by transferring electrons from one atom to another whereas covalent bond occurs as a result of sharing valence electrons between atoms. An ionic bond is also called an electrovalent bond. Valence electrons, which are electrons located in the outermost shells of an atom, are involved in both types of chemical bonding.
Chemical bonding is the key to forming various types of chemical compounds. It acts as a glue to hold atoms or molecules together. The main purpose of chemical bonding is to produce a stable chemical compound. When a chemical bond forms, energy is released, forming a stable compound. There are three major types of chemical bonds known as ionic bond, covalent bond, and metallic or non-covalent bond.
CONTENTS
1. Overview and Key Difference
2. What is an Electrovalent Bond
3. What is a Covalent Bond
4. Side by Side Comparison – Electrovalent vs Covalent Bond
5. Summary
What is an Electrovalent Bond?
Electrovalent or ionic bond is a type of chemical bond which is formed as a result of transferring electrons from one atom to another. This transfer causes one atom to get positively charged and the other atom to get negatively charged. The electron donor atom becomes positively charged; hence, it is called the cation whereas, the electron receiving atom becomes negatively charged and is called the anion. An electrostatic attraction arises between this cation and anion due to opposite electrical charges. The large difference in electronegativity between the two atoms causes this bonding to occur. Both metallic and non-metallic atoms are involved in this bonding.
However, none of the electrovalent bonds are pure ionic bonds. Each and every ionic compound may have some percentage of covalent bonding. Thus, it reveals that an ionic compound has a greater ionic character and a low degree of covalent character. But there are some compounds with a considerable degree of covalent character. That type of bonding is called polar covalent bonds.
The characteristics of compounds that are built from electrovalent bonding are different from the compounds built from covalent bonding. When considering the physical properties, typically higher boiling points and melting points can be observed. But the solubility in water and the electrical conductivity property is considerably high. Examples of compounds with ionic bonds may include halides of metals, oxides of metals, sulfides of metals, etc.
Figure 01: Electrovalent Bond
What is a Covalent Bond?
A covalent bond is a type of chemical bonding which is formed as a result of sharing electron pairs between non-metal atoms. This electron sharing is occurred due to low electronegativity difference between the two atoms involved in bonding. In covalent bonding, non-metal atoms are typically involved. These atoms have an incomplete electron configuration in their outer orbitals, thus, share unpaired electrons in order to achieve electron configuration similar to a noble gas. That is because incomplete electron configuration makes the particular atom unstable. Unlike ionic bonding, covalent bonding may have single, double bonds or triple bonds between two atoms. These bonds are formed in such a way that the two atoms obey the octet rule. The bond occurs via the overlapping of atomic orbitals. A single bond is formed when two electrons are shared. A double bond is formed when four electrons are shared. Sharing of six electrons may result in a triple bond.
The characteristics of compounds with covalent bonds include strong bonding between two atoms due to similar electronegativity values. Thus, solubility and electrical conductivity (in soluble state) are poor or absent. These compounds also have lower melting points and boiling points compared to ionic compounds. A number of organic and inorganic compounds can be taken as examples of compounds with covalent bonding.
Figure 02: Covalent Bond
What is the difference between Electrovalent Bond and Covalent Bond?
Electrovalent Bond vs Covalent Bond |
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| Electrovalent bond is a chemical bond between two atoms due to a transfer of electron(s) from one atom to the other. | Covalent bond is a type of chemical bond which occurs due to sharing of electron pairs between atoms. |
| Metals vs Non-Metals | |
| Electrovalent bonds can be observed between metals and non-metals. | Covalent bonds can be typically observed between two non-metals. |
| Difference in Electronegativity | |
| The difference in electronegativity between two atoms is higher in electrovalent bonding. | The difference in electronegativity between two atoms is comparatively lower. |
| Solubility in Water and Electrical Conductivity | |
| Solubility in water and electrical conductivity is higher in compounds with electrovalent bonding. | Solubility in water and electrical conductivity is comparatively lower in compounds with covalent bonding. |
| Boiling and Melting Points | |
| Boiling and melting points are higher for electrovalent bonding. | Boiling and melting points are comparatively lower for covalent bonding. |
Summary – Electrovalent vs Covalent Bonds
Electrovalent and covalent bonds are two types of chemical bonds which are different from each other. The major difference between electrovalent and covalent bonds is their nature; electrovalent bond is a type of electrostatic attraction between two atoms whereas covalent bond is sharing of electron pairs between two atoms.
Reference:
1. “Electrovalent Bonding.” EMedicalPrep. N.p., n.d. Web. 25 May 2017.<<https://www.emedicalprep.com/study-material/chemistry/chemical-bonding/electrovalent-bonding/>>
2.”The Covalent Bond .” Chemical Education Division Groups. Purdue University, n.d. Web. 25 May 2017.<<http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch8/valenceframe.html>>
3.”Chemical bonds.” Khan Academy, n.d. Web. 25 May 2017. <<https://www.khanacademy.org/science/chemistry/chemical-bonds>>
Image Courtesy:
1. “NaCl ionic bond” By Mhowison – Own work (Public Domain) via Commons Wikimedia
2. “Covalent bond hydrogen” By Jacek FH – Own work (CC BY-SA 3.0) via Commons Wikimedia
