Interhalogen Compounds: Classification, Structure and Example

Interhalogen compounds are very a hot area of chemistry that is a result of the combination of two halogen atoms that react into distinct molecules containing particular properties. Everyday items include species that are formed by the reaction of the halogens that mention the compounds of Group 17 of the periodic table, inclusive of fluorinated compounds classified as reacting and interhalogens, which are stable. Understanding interhalogen compounds is very key for a student or chemist and to any application, of course, in the daily life of general interest. A paper of this kind will much detail give the definition and the key features of interhalogens.

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This Story also Contains

1. Physical Properties of Group 13 - 1
2. Preparation
3. Physical Properties of Group 13 — 2
4. Summary

Physical Properties of Group 13 - 1

While most of these interhalogens have their physical properties contrasting to one another, it is the only thing that shows their specific configuration.

They normally have low boiling as well as melting points in most cases compared to their corresponding halogen elements. The molecular size and the nature of the bonding of the interhalogens have resulted in different volatilities and stability. Most of the interhalogen compounds are gases or liquid in normal room temperatures which is in complete contrast to the halogens that exist as solids. Again, this is revealed by the specific halogens that are involved in the molecule. For example, interhalogens containing fluorine are normally most easily reacted upon. They also exhibit varying behavior in solubility as compared to those containing iodine. These physical behaviors thus become important to enable imagination of how the interhalogens will behave under a particular reaction and hence industrial use of the interhalogens.

When two different halogens react with each other, interhalogen compounds are formed. They can be assigned general compositions as XX′, XX₃′, XX₅′, and XX₇′ where X is halogen of larger size and X′ of smaller size, and X is more electropositive than X′. As the ratio between radii of X and X′ increases, the number of atoms per molecule also increases. Thus, iodine (VII) fluoride should have a maximum number of atoms as the ratio of radii between I and F should be maximum. That is why its formula is IF₇ (having a maximum number of atoms).

Preparation

The interhalogen compounds can be prepared by the direct combination or by the action of halogen on lower interhalogen compounds. The product formed depends upon some specific conditions, For example,

$\begin{aligned} & \mathrm{Cl}_2+\mathrm{F}_2 \xrightarrow{437 \mathrm{~K}} 2 \mathrm{ClF} \\ & \mathrm{I}_2+3 \mathrm{Cl}_2 \rightarrow 2 \mathrm{ICl}_3\end{aligned}$

$\begin{array}{r}{\mathrm{Cl}}_2+{\mathrm{F}}_2\stackrel{437\mathrm{K}}{\to }2\mathrm{ClF}\\ {\mathrm{I}}_2+3{\mathrm{Cl}}_2\to 2{\mathrm{ICl}}_3\end{array}$

Properties

Some properties of interhalogen compounds are given in the following table.

These are all covalent molecules and are diamagnetic in nature. They are volatile solids or liquids at 298 K except ClF which is a gas. Their physical properties are intermediate between those of constituent halogens except that their m.p. and b.p. are a little higher than expected.
Their chemical reactions can be compared with the individual halogens. In general, interhalogen compounds are more reactive than halogens (except fluorine). This is because the X–X′ bond in interhalogens is weaker than the X–X bond in halogens except the F–F bond. All these undergo hydrolysis giving halide ion derived from the smaller halogen and a hypohalite ( when XX′), halite (when XX′₃), halate (when XX′₅), and perhalate (when XX′₇) anion derived from the larger halogen.

$\mathrm{XX}^{\prime}+\mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{HX}^{\prime}+\mathrm{HOX}$

${\mathrm{XX}}^{\prime }+{\mathrm{H}}_2\mathrm{O}\to {\mathrm{HX}}^{\prime }+\mathrm{HOX}$

Their molecular structures are very interesting and can be explained on the basis of VSEPR theory. The XX₃ compounds have the bent ‘T’ shape, XX₅ compounds are square pyramidal, and IF₇ has pentagonal bipyramidal structures.

Physical Properties of Group 13 — 2

Physical properties, by themselves, also play a role in the reactivity and stability of inter-halogen compounds. The potential with compounds having dipole-dipole interaction presents different reactivity. Lone pairs on the central atom, and differences in electronegativity between the halogens, will themselves constitute determinant features for the molecular geometry that affects the chemical behavior.

Hence, these characteristics of their nature exert intermolecular forces between the atoms of interhalogen compounds: this can change their behavior under physical states and phases, often very beneficial in some sorts of applications.

For example, some of the interhalogen compounds can be exploited in the form of an oxidizing agent, while others can be utilized in selective organic synthesis cases as a halogenating agent. Knowing these properties not only helps in laboratory practices but also reveals treasures hidden behind their importance for technological applications. Relevance and Applications of Interhalogen Compounds

Interhalogen compounds are very important in strong character not only in an academic research field but also in applications. They are very important in synthetic chemistry due to their unique reactivity in synthesizing elements into more complex molecules and even in a reaction mechanism of said molecule. For instance, some interhalogen is used to make organohalides constituting intermediates for agrochemicals and pharmaceuticals.

Furthermore, it is possible to synthesize from these compounds some advanced materials, especially on polymers and fluorinated substances, with exceptional properties of higher strength and thermal resistance. The use of interhalogens having a number of limited compounds in the sphere of environmental science has been known from their possibilities of involvement in cleaning pollution through the processing of waste raw materials.

Industrially, these compounds are used in disinfectants and cleaning agent applications since they show good biocidal activity. These compounds have an important role in our daily life, from house applications to industry.

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Some Solved Examples

Example 1
Question: The number of 90° angles in IF₅ are:

1) 8
2) 5
3) 6
4) Zero (correct)

The IF₅ molecule is sp³d² hybridized and has a square pyramidal shape. Due to lone pair-bond pair repulsion, there is distortion in the molecule, resulting in no 90° bond angles. Hence, the correct answer is Option (4).

Example 2
Question: The shape of ClF is:

1) Linear (correct)
2) Triangular planar
3) Tetrahedral
4) Octahedral

Solution: ClF is a diatomic molecule, which is linear in shape. Hence, the answer is Option (1).

Example 3
Question: The shape of IF₃ is:

1) V-Shaped
2) T-Shaped (correct)
3) Trigonal Planar
4) Trigonal Bipyramidal

Solution: The shape of IF₃ is T-shaped. Hence, the correct answer is Option (2).

Summary

The interhalogen compounds are interesting chemical species that unitize the different varieties of halogens. Their unique physical properties reactivity and applicability in real-life situations made them pretty much a significant aspect in relation to both the academic chemistry system, announced earlier, and the practical application systems nowadays. The author of this paper gives a description about the basics of interhalogen compounds, more specifically physical properties and types, and areas of application.