[Solved]- Covalent Bond Stronger than an Ionic Bond?-A Complete Guide

Covalent bond stronger than an ionic bond

Whenever a word bond to hear it means to tie something together. Chemical means we cannot separate (irreversible) by physical means. There is an attractive force that keeps two atoms together in a molecule. In the formation of molecules, only electrons present in the outermost shell or valence shell of the atom normally participate.

The electrons belonging to the inner energy shell are mostly not involved in the formation of the bond. Atoms may attain stable electronic configuration in three different ways by losing, gaining, or by sharing electrons. Ionic and Covalent bonds form to achieve: Minimum Energy and Maximum Stability.

Are Covalent Bond Stronger than Covalent Bonds?

Ionic bonds are stronger than covalent bonds. The reason because in an ionic bond, there is a complete transference of one or more electrons from one atom to another to complete octets. During complete transference, one losses electrons become positive, and the other gains electrons achieve negative, thus forms huge electrostatic forces of attraction. Whereas, in covalent, sharing of electrons between two similar or different atoms takes place. Only a partial charge develops on both of the atoms. So, that is why a covalent bond is not stronger than an ionic bond.

Who is stronger a covalent or ionic bond

As I said to you before, The formation of bonds between atoms takes place in many ways in response to the electronic configuration of the outermost shell of the combining atoms. When it comes to ionic and covalent comparisons, Ionic bonds are stronger than covalent. This can be easily identified through the change in important characteristics (behavior) of both ionic as well as covalent but with a few exceptions.

You can read: Covalent Bond Structure and their Properties

Chemical Bonds

All known elements do not exist in free nature due to their reactivity with various reagents. Only few elements which is placed in last group of periodic table has completely filled octet configuration and also termed as noble gases.

All other elements have tendency to attain octet configuration by formation of compounds. Electrons, especially those of the outermost valence electronic shell, play a fundamental role in chemical bonding. In some cases chemical bonding results from the transfer of one or more electrons from one atom to another. This leads to the formation of positive and negative ions.

The bond is known as ionic bond. In other cases chemical bonding results from a mutual sharing of electrons between atoms. This leads to the formation of molecules having a bond called a covalent bond.

The transfer or sharing of electrons occurs to the extent that each atom involved acquires an especially stable electron configuration. Often this configuration is that of a noble gas (ns2np6), that is, involving eight outer-shell electrons called an octet.

What is a Chemical Bond?

The process of combination involves the reunion of two or more atoms through redistribution of electrons in their outer shells either by the process of sharing of electrons amongst themselves so that all the atoms acquire the stable noble gas configuration of minimum energy, is called as chemical bond.

Types of Chemical Bond

On the basis of transfer of electrons; chemical bonds can be different types.

  1. Ionic bond
  2. Covalent bond
  3. Metallic bond
  4. Van der wall force
  5. Coordinate bond

Ionic bond

An ionic bond is formed by the complete transfer of one or more electrons from the valence shell of an atom to the valence shell of the other atom. Hence in ionic bond there is complete transfer of electron from one atom to another. The atom which loses the electron and gets positive charge is known as cation, while another anion termed as anion, getting negative charge.

The electrostatic force of attraction between oppositely charged ions results in the formation of ionic bond or electrovalent bond. Compounds involve in ionic bond are known as ionic compound or electrovalent compound. Generally those atoms involve in ionic bond formation, which have either high electronegativity or high electro positivity.

For example: Sodium atom lose its valence shell electron and form sodium ion (Na+), while chlorine accept one electron to attain octet, and form chloride ion (Cl). The electrostatic force of attraction between sodium ion and chloride ion is known as ionic bond.

Read More: Sodium Chloride NaCl

Ionic compounds have high melting point and boiling point due to strong attraction of force between ions. They are hard and good conductor of electricity.

Covalent bond

This type of bond formed between two non-metals. When two same or different atoms shared their valence electron to attain the noble gas configuration, it’s known as covalent bond. For example; for attaining the nearest noble gas configuration, each hydrogen atom share its valence electron with other hydrogen atom and form a covalent bond in hydrogen molecule.

covalent bond in hydrogen molecule

Two hydrogen atoms come close to each other, the nuclei of one will attracted by electrons of other and vice. Formation of any chemical bond involves decreasing in energy level. When two atoms approach towards each other, new attraction and repulsion forces set in. If the net result is attraction force; the total energy of the system decreases and chemical bond formed. If the net result is repulsion force, the total energy of system will increases and no chemical bond is possible.

For example: when the two hydrogen atoms approaches towards each other, the potential energy of the system decreases because of the force of attraction. At a particular distance between atom nuclei, the value of potential energy reaches a minimum. When the forces of attraction and repulsion balance each other and the potential energy reached to minimum, covalent formed in molecule.

Due to decreasing energy the covalent bond formed in molecule. The decrease in potential energy continues till a certain minimum value and the formation of molecule takes places at minimum energy value in potential energy curve. At the minimum energy level, there is a minimum distance between nuclei and this minimum distance is called as bond length.

potential-energy-curve-H2-molecule.png

Hence the 1s orbital of two hydrogen atoms overlapped two form covalent bond. When a covalent bond forms due to the overlapping of orbitals along the same axis, it’s known as sigma bond. This type of overlapping takes place to substantial extent and the resulting bond is very strong covalent bond.

Covalent bond can be formed by overlapping along same axis and by the side way overlapping of orbitals. The overlapping along axis forms sigma bond whiles the sidewise overlapping of half filled orbitals form pi bond. Out of these two bonds, sigma bond is stronger than pi bond, hence pi bond always exist with sigma bond.

Single Covalent Bond


In a compound all atoms bonded with sigma covalent bond only, than these bonds are termed as single covalent bond.
For example: Ethane (C2H6), in which each carbon form one sigma covalent bond with another carbon atom and three sigma covalent bonds with three hydrogen atoms.

All are sigma covalent bond formed by axial overlapping of sp3 hybridized orbitals of carbon atom. If a carbon atom forms only single covalent bond, it’s hybridization will be sp3. Four sp3 hybridized orbital arranged in tetrahedral manner with 109°28’ bond angel and overlap with 1s orbital of three hydrogen atom and one sp3 orbital of another carbon atom.

Double Covalent Bond

  1. When two pairs of electrons are shared between the atoms rather than just one pair, it formed double covalent bond.
  2. There is one sigma and one pi bond in a double covalent bond. The double covalent bond is shown by two lines joining the bonding atoms where each line represents one pair of shared electrons.

Double Covalent Bond Examples


The simplest example of double covalent bond is oxygen molecule (O2) where two oxygen atoms attains the octet configuration by sharing two pairs of electrons with each other.

double covalent bond is oxygen molecule

Another example of double covalent bond is carbon dioxide in which center carbon atom is sp hybridized and form two double covalent bond with two oxygen atoms.

Read More:  Carbon Dioxide CO2 Ionic or Covalent Bond?

Apart from carbon dioxide; ethene is another example of double covalent bond with carbon atom.
Ethene contains one carbon –carbon double covalent bond and four single covalent bonds between carbon and hydrogen atoms.

Carbon atom with 1s2, 2s2, 2px1, 2py1 electronic configuration needs to promote one of the 2s2 pair into the empty 2pz orbital for making four unpaired electron required for the formation of four covalent bonds.

In ethene each carbon is joined with three other atoms rather than four. Hence the carbon atoms hybridize by using their valence orbitals before forming bonds but only hybridize three of the orbitals rather than all four. So each carbon atom use the 2s electron and two of the 2p electrons and leave the other 2p electron unchanged.

ethene-bonding

These new sp2 hybrids arrange themselves in trigonal planer geometry with 120° bond angle. The unhybridized p- orbitals on both carbon atoms exist at right angles to the hybridized orbitals.

These unhybridized orbitals overlapped in sideways manner and form a molecular orbital, but of a different from sp2 orbitals. In this one the electrons are held above and below the plane of the molecule results in the formation of a pi bond.

ethene-molecule1.png

Triple Covalent Bond


A covalent bond formed with three pairs of electron is called as triple covalent bond. It represented by three straight lines between bonded atoms. Out of three bonds, one is sigma and another two are pi bonds. Since the presence of pi bonds make the molecule unsaturated, hence molecules with triple bonds show additional reactions. They show positive test with Bayer reagent and decolorize the bromine water solution.

Triple Covalent Bond Example


There are many molecule consist triple bond between two bonding atoms. For example; nitrogen molecule, in which each nitrogen atom has five electrons in its valence shell and required three electrons to complete the octet. Hence each nitrogen atom can form three bonds results in the formation of nitrogen molecule with one triple covalent bond.

Another example of triple covalent bond is ethyne molecule which consist a triple bond between two carbon atoms. In this molecule, each carbon atom is Sp-hybridized and generates two sp-hybrid orbitals. These hybrid sp orbitals are arranged in linear geometry and with 180o bond angle.

Remaining two py and pz un hybridised orbitals of each carbon atom which lie perpendicular to the plane of sp-orbitals involve in the formation of pi-bond. Out of two sp-hybrid orbital of each carbon atoms , one overlaps with 1s orbital of hydrogen to produce one sigma bond between Carbon and Hydrogen atoms.

While the other sp-orbital overlaps with another sp orbital of next carbon atom to form sigma bond with another carbon atom. The triple covalent bond is quite shorter than single and double covalent bonds with 1.09Å of carbon –hydrogen bond length and 1.2Ao C-C bond length. The bond angle is 180° with linear geometry.

Single Double and Triple Covalent Bonds


Covalent bonds can be three type depends upon the number of electrons involve on bond formation. Each type of covalent bond shows unique characteristics.

  • Single covalent bond – 1 shared pair or two electrons. For example; fluorine molecule (F:F or F-F or F2) , other examples are H2, F2, I2 and other diatomic molecules.
  • Double covalent bond – 2 shared pairs or four electrons. For example; oxygen molecule ( O::O or O=O or O2), other examples are O2, CO2 and HCHO.
  • Triple covalent bond – 3 shared pairs or six electrons. For example; Nitrogen molecule ( :N:::N:, N=N or N2) , ethyne (C2H2 ).
  • As the number of bond increases, bond energy increases. Hence the increasing order of bond energy is, Single < Double < Triple covalent bond
  • However the bond length decreases with increasing the number of bonds. Hence the decreasing order of bond length is, Single > Double >Triple covalent bond

Compare and Contrast Ionic and Covalent Bonds

Ionic BondCovalent Bond
It is generally formed of the metals and nonmetals.The bond is formed between the two nonmetals.
The metal atom loses one or more electrons present in its valence shell and these electrons accept by the nonmetallic atom. Each combining atom must contribute at least one electron to the shared pair.
One of the species is cation and the other is an anion. By losing electrons, the metal atom changes to a (positive ion) cation. Similarly, the nonmetal atom gaining the electrons, get a change to a (negative Ion) anion. The oppositely charged ions attract each other. The combining atoms mutually contribute one, two or three electrons depending upon their requirement the bond formed. This leads the formation of single double and triple bond. Double and triple bond are not stronger than ionic bond as there is sharing of electrons.
 Ionic bond possible only when one of the species must have low ionization energy and the other should have high electron affinity. The electronegativity difference between the two atoms should be less.

Ionic Bond Characteristics

  1. Crystal structure: Ionic compounds are crystalline solids in which ions are arranged in a certain definite pattern to form a crystal lattice. For example, in case of sodium chloride, each sodium ion is surrounded by six chloride ions and each chloride ion by six sodium ions, thus giving rise to a three-dimensional crystal structure.
  2. Non-directional character: In ionic compounds, the oppositely charged ions are held together by the electrostatic force of attraction. As a charge is distributed symmetrically around the ion. So ionic bond has no direction, each cation is surrounded by a number of anions and vice versa.
  3. High melting point and boiling point: Since the ions are held together by a strong electrostatic force of attraction, a large amount of energy is required to separate the ions. So ionic compounds have a high melting point and boiling point.
  4. Electrical conductance: Since the ionic compounds ionize in a molten state or in aqueous Solutions, they conduct electricity in solution or in a fused state. However, they do not conduct electricity in solid-state.
  5. Ionic reaction: The reactions of ionic compounds are the reactions of their ions which are very fast.

Covalent Bond Characteristics

  1. Physical State: Unlike ionic compounds (which generally exist as solids), the covalent compounds exist in all the three states, viz, solid, liquid and gaseous.
  2. Crystal Structure: They usually consist of individual molecules rather than crystalline giant structures.
  3. Electrical conductivity: Since there are no free ions in covalent compounds to conduct electricity, they are bad conductors of electricity. These are nonelectrolytes.
  4. Melting and Boiling Points. Covalent compounds have low melting and boiling points because the molecules in covalent compounds are held together less rigidly (by weak van der Waal’s forces), than in the case of ionic compounds.
  5. Non-ionic reactions: Since these compounds like CH3Cl or CCI4 are molecular in nature and not ionic, their reactions are molecular and proceed at a much slower rate than those of ionic compounds.
  6. Directional Character and Isomerism: The covalent bond has a directional character, unlike electrovalent bonds. Due to a directional character of the bond, these molecules show isomerism i.e. one molecular formula may represent two or more than two structural formulae called isomers and this phenomenon is called isomerism.

are covalent bonds stronger than ionic bonds in water?

Ionic bond in water splits and gets separated thus no longer a stronger bond. It turns into ions while covalent remain non-soluble in water.

When an ionic compound is dissolved in water, the force of attraction between ions is weakened and thus the ionic compound splits into ions. In other words, ionization of the compound takes place. Whereas, Covalent compounds are generally soluble in organic (non-polar or weakly polar) solvents but insoluble in water and other polar solvents.

is an ionic bond stronger than a nonpolar covalent bond?

Ionic bonds are stronger than a nonpolar covalent bond like CH4, as they belong to a covalent family. However, “Like dissolves like” is the principle behind the solubility of a compound. Ionic compounds are usually soluble in polar solvents like water but insoluble in non-polar solvents like benzene and ether.

Similarities Between Ionic and Covalent Compounds

The similarity between ionic and covalent only exists in exceptions. Ionic Compounds are generally hard. Similarly diamond is a hard solid like ionic compounds. Ionic compounds are the good conductor of electricity. An exception of graphite in a covalent bond is also a good conductor of electricity.

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References:

https://www.thoughtco.com/ionic-and-covalent-chemical-bond-differences-606097