Interhalogen Compounds

An interhalogen compound is a molecule that contains two or more separate halogen atoms (fluorine, chlorine, bromine, iodine, or astatine) and no atoms of any other group of elements. Most known interhalogen compounds are binary (composed of only two distinct components).

Popular interhalogen compounds include chlorine monofluoride, bromine trifluoride, iodine pentafluoride, iodine heptafluoride, etc. Interhalogen compounds are compounds formed when halogen-group elements react with each other.

In other words, it is a molecule composed of two or more separate elements of group 17. There are four forms of interhalogen compounds available:

  • Diatomical interhalogens (AX)

  • Tetratomic interhalogens (AX3)

  • Hexatomical interhalogens (AX5)

  • Octatomical interhalogens (AX7)

A halogen with a large size and high electropositivity interacts with a group of 17 products with a small size and lower electropositivity. As the ratio of the radius of larger and smaller halogens increases, so does the number of atoms in the molecule.

Types of InterHalogen Compounds

Contingent on the number of atoms in the molecule, the interhalogens are classified into four groups.

They 're:

  • XY

  • XY3

  • XY5

  • XY7

"X" is larger (or less electronegative halogen and "Y" is smaller (or more) electronegative halogen.

Using the radius ratio, we can calculate the number of particles in the atom.

Radius Ratio = Radius of Bigger Halogen Particle / Radius of Smaller Halogen Molecule

As the radius proportion increases the number of atoms per molecule, so does the rise. So Iodine heptafluoride has the largest number of particles per atom out of all interhalogen compounds because it has the most impressive radius proportion.

Preparation of Interhalogen Compounds

These molecules are formed by a direct combination or by the action of a group 17 element with a lower interhalogen compound under specific conditions. For example, at 437 K, chlorine reacts with equal volume fluorine to form ClF. This process is commonly used in the manufacture of group 17 fluorides.

Cl2 +F2 → 2ClF (473K)

I2 + Cl2 → 2ICl

Properties of Interhalogen Compounds

Interhalogen compounds are found in a vapour state, in a solid-state or in a liquid state. We may find interhalogen compounds in gas, solid, or liquid state. A number of these substances are unstable 298 K solids or fluids. There are also a few other substances that are gases. For example, chlorine monofluoride is a gas. On the other hand, trifluoride bromine and trifluoride iodine are both solid and liquid.

  • Most of these compounds are liquid solids (or fluids) at 298 K, while the rest is gaseous.

  • For example, chlorine monofluoride exists as a gas, while bromine trifluoride and iodine trifluoride exist separately as a solid and liquid state.

  • All of these compounds are covalent in nature due to a less electronegativity distinction between bonded molecules. For example, chlorine monofluoride, bromine trifluoride, iodine heptafluoride is of a covalent nature.

  • Both of these interhalogen compounds are diamagnetic in nature because they have only bond pairs and lone pairs. These interhalogen compounds are diamagnetic in nature. This is because they have bond pairs and lone pairs.

  • In contrast to other constituent halogen compounds, the interhalogen compounds are more reactive (apart from fluorine). This is because the bond of A-X in interhalogens is weaker than the bond of X-X in halogens other than the bond of F-F.

  • Interhalogen compounds are highly reactive. Fluorine is an exception to this. This is because the bond of A-X in interhalogens is much weaker than the bond of X-X in halogens, except for the bond of F-F.

 Uses of Interhalogen Compounds

  • They are used as non-aqueous solvents / non-watery solvents.

  • We use these compounds as a catalyst in a number of reactions.

  • In a few reactions, they are used as catalysts.

  • UF6 used to enrich 235 U is provided using ClF3 and BrF3.

  • U(s) + 3ClF3(l) and UF6(g) + 3ClF(g)

Preparation of Interhalogen Compounds

These interhalogen compounds can be produced using two main methods. One of them involves the direct mixing of halogens and the other involves the reaction of halogens to the lower interhalogen compounds.

  • Halogen atoms are combining to form an interhalogen compound. One example is the reaction when the volume of chlorine reacts with an equal volume of fluorine at 473K. The resultant product is chlorine monofluoride.

  • In other cases, the halogen atom acts with a lower interhalogen to form an interhalogen compound. For example, fluorine reacts to 543 K with iodine pentafluoride. This results in a compound of Iodine Heptafluoride.

FAQ (Frequently Asked Questions)

1. What are Interhalogen Compounds with Examples? How are Interhalogen Compounds Formed? Why are Interhalogens More Reactive than Halogens?

Interhalogen compounds are halogen subordinates. Compounds containing two distinct forms of halogens are referred to as interhalogen compounds. Example: monofluoride chlorine, trifluoride bromine, pentafluoride iode, heptafluoride iode, etc.

Halogens react to outline interhalogen compounds with each other. The general condition of most interhalogen compounds is XYn, where n = 1, 3, 5, or 7 is the less electronegative of the two halogens. Compounds that are encircled by the union of two halogens are referred to as interhalogen compounds.

In certain cases, interhalogens are more reactive than halogens other than F. This is because the A-X bonds in the interhalogens are weaker than the X-X bonds in the di-halogen particles. Inter-halogen reactions are the same as halogen reactions. Hydrolysis of the interhalogen compounds produces oxy acid and halogenic acid.

2. Can Fluorine Ever Be a Central Atom? Why Can’t Hydrogen Be the Central Atom?

Fluorine can not be a central particle in interhalogen compounds. This is because it is part of the second cycle of the periodic table. Since it has 7 valence electrons, it can only form one bond.

Hydrogen is not the central atom. We can attribute this to the fact that the atom will always try to achieve the most minimal energy. In the case of hydrogen, this means that it can only form a single bond. It also has a very small size and does not fit into the other molecules around it.