13 Facts On KrF4 Lewis Structure & Characteristics

Krypton tetrafluoride is a molecule in which krypton is attached to four fluorine atoms. It has a 159.79 molecular weight. Let us discuss in detail.

Krypton tetrafluoride is a organic chemical entity which is white colour solid in nature. It is thermally less stable than xenon tetrafluoride. Structurally it is form by central krypton and four fluorine atom.

Lewis structure of compound can be influence by various factors. Let us discuss the various factors of KrF4 below.

How to draw KrF4 Lewis structure ?

Lewis structure of any molecule is a structural representation in which the electrons are represented by dot . Lewis structure of any molecule can be drawn by the following facts.

Step : 1

In the krypton tetrafluoride Lewis structure, Krypton (Kr) is a non-metal and fluorine is a gas. Which are present in the 17th and 18th group of the periodic table respectively. So, Fluorine has 7 valence electrons while krypton has 8 valence electrons in the KrF4 molecule.

Step: 2

Krypton tetrafluoride has total 38 valence electrons. Out of which 4 fluorine atom has 28 valence electrons. And remaining 8 valence electrons are present in krypton atom. Krypton is placed in the center because it has less electronegativity as that of fluorine atom.

Step : 3

Krypton tetrafluoride has 18 bond pairs of electrons. Out of this four Kr-F bonds contain 4 electron pairs remaining 14 pairs of electrons are denoted as lone pair of electrons. All the lone pairs of electrons are denoted by dot and bond pairs of electrons are denoted by covalent bond.

KrF4 Lewis structure resonance

Lewis structure resonance effect occurs due to delocalization of electrons around double bond and lone pair of electrons. Let us find out the resonance.

KrF4 Lewis structure does not show resonance. Because it has all four single bonds hence it does not undergo delocalization of electrons. Which generally happens in the case of the presence of a double bond. Double bonds are not present in the KrF4 molecule for delocalization.

KrF4 Lewis structure shape

The Lewis structure shape of KrF4 molecules can be determine according to VSEPR theory. Let us determine the shape of the molecule is as follows.

The shape of KrF4 Lewis structure is square planer due to Sp3d2 hybridization. With the central krypton atom and four fluorine atoms. According to VSEPR theory krypton tetrafluoride molecule shows that shape. Which is form by one krypton and four fluorine atom.

Lewis structure shape of KrF4

KrF4 Lewis structure formal charge

The formal charges of any molecule is calculated by the no of valence electrons , no of non bonding electrons and no. of bonding electrons. Let as calculate the formal charge.

 Formal charge in KrF4 molecule = No. of valence electrons (V) – No. of non–bonding electrons (N) – No.of bonding electrons B/2

  • Formal charge of Kr in KrF4 Lewis structure = 8 – 4 – ½ (8) = 0
  • Formal charge of F in KrF4 Lewis structure= 7 – 6 – ½ (2) = 0
  • In the krypton tetrafluoride (KrF4) molecule the Krypton and fluorine have zero formal charges.

KrF4 Lewis structure angle

The bond angle in Lewis structure can be determine by the shape and geometry of the molecule. Let us discuss about the bond angle.

The KrF4 has bond angle at F-Kr-F 90o and F-Kr-F 180o. Due to square planer geometry all the fluorine atoms arrange perpendicular to krypton atom.

Due to different equatorial and axial position of fluorine atom. KrF4 molecule shows two different bond angles at 90o and 180o.

KrF4 Lewis structure octet rule

Lewis structure octet rule possess the same valence shell electronic configuration as that of its nearest inert gas . Let us describe octet rule.

KrF4 Lewis structure octet rule requires eight electrons to complete

its octet . In the case of the krypton tetrafluoride molecule, it contains Krypton and fluorine atoms. Fluorine atom contains 7 valence electrons and krypton has 8 valence electrons.

All fluorine get two electrons from central krypton atoms and the rest 6 electrons form three lone pairs on fluorine atom. While krypton has 8 valence electrons it combines with four fluorine atoms and shares 8 electrons with them and the remaining four electrons form two lone pairs.

KrF4 Lewis structure lone pairs

The lone pair of electrons which are not involved in bond formation. Let us find out the Lewis structure lone pair of KrF4 molecule.

In Krypton tetrafluoride Lewis structure 14 lone pairs of electrons are present. Out of them two lone pairs are on the krypton atom and the remaining 12 lone pairs of electrons are present on four fluorine atoms.

These lone electron pairs are not participated in the bond formation in the krypton tetrafluoride molecule.

KrF4 valence electrons

Valence electrons are the last outermost shell electrons. Which are more reactive hence form a bond between the atoms in the molecule. Let us discuss valence electrons below.

Krypton tetrafluoride molecule has total 36 valence electrons. Out of them four krypton atom has 28 valence electrons. And krypton has 8 valence electrons.

Therefore, krypton tetrafluoride molecule has 8+28=36 valence electrons present in the KrF4 molecule.

KrF4 Hybridization

Hybridization is the process in which the atomic orbitals combine and form a new hybrid orbital. We can explain hybridization in KrF4 molecule are as follows.

Krypton tetrafluoride molecule has sp3d2 hybridization. It is formed by one krypton atom and four fluorine atoms. According to VSEPR theory it has square planer geometry .

Hence in krypton tetrafluoride molecule three Sp3 and two d orbitals combines to form five sp3d2 hybrid orbitals.

Is KrF4 polar or nonpolar?

Polarity of any molecule depends upon its electronegativity difference and bonding between the molecule. Let us find out the polarity of KrF4 is as follows.

KrF4 is non polar in nature. When the molecules are loosely bound then they are non polar in nature. While the molecules are closely bound then it is polar in nature.

Why KrF4 is non polar?

The electronegativity difference between krypton and fluorine is 0.98. Due to less electronegativity difference between the fluorine and krypton atom. They are loosely bound with each other.

The bond of the KrF4 molecule are weekly attracted towards each other. Therefore Kr-F bond in the krypton tetrafluoride molecule is non polar in nature.

Is KrF4 tetrahedral?

In tetrahedral geometry the central atom is at the center of the tetrahedron and four atoms are at the four corners of tetrahedron. Let us tell about the geometry of KrF4 molecule.

Krypton tetrafluoride does not show tetrahedral shape because it has a square planer geometry due to sp3d2 hybridization. It has two lone pairs of electrons one above and one below the plane. While tetrahedral geometry shows sp3d hybridization.

Is KrF4 ionic or molecular?

Ionic and molecular character of the molecule can be find out from the structure and electron sharing of the molecule. Let us discuss the ionic or molecular characteristic below.

Krypton tetrafluoride is molecular means covalent in nature. It forms a bond by sharing electrons between krypton and fluorine. Also by electron pairs between them. Both krypton and fluorine have nearly the same electronegativities. Which form a covalent bond between them.

While dissociation KrF4 molecule does not dissociates into ions like Kr+ and F. Krypton and fluorine are attach by covalent bond with each other hence it shows molecular nature .

Is KrF4 trigonal pyramidal?

In trigonal pyramidal geometry the central atom is at the center of triangle and three atoms are on the corners of triangle. And remaining two atoms are above and below the plane.

Krypton tetrafluoride does not show trigonal pyramidal geometry because it has sp3d2 hybridization which shows square planer geometry. While sp3d hybridization shows trigonal bipyramidal geometry.


In the above article, we will describe the Lewis structure of krypton tetrafluoride and their various fact like hybridization, valence electrons, the shape , lone pairs , polar or non-polar nature of the molecule in detail.

Darshana Fendarkar

Hi....I am Darshana Fendarkar, I have completed my Ph.D. from the University of Nagpur. My area of specialization is Inorganic Chemistry. I have an experience as a Chemist at Earthcare Pvt. Ltd. Also I have 2 years of experience in teaching. Currently, I am working with Lambdageek as a Subject Matter Expert. Let's connect through LinkedIn-https://www.linkedin.com/in/dr-darshana-fendarkar-00380540

Recent Posts