LiF Lewis Structure,Geometry,Hybridization: 7 Steps (Solved)

Lithium fluoride (LiF) consists of lithium (Li) with 1 valence electron and fluorine (F) with 7 valence electrons. The Lewis structure represents LiF as an ionic compound: Li donates its electron to F, forming Li⁺ and F⁻ ions. This electron transfer achieves a stable octet for F and an empty valence shell for Li. In the crystalline structure, each Li⁺ ion is surrounded by six F⁻ ions in an octahedral coordination, and each F⁻ ion is surrounded by six Li⁺ ions, forming a cubic lattice. LiF’s ionic nature contributes to its high melting point (845°C) and its role as an insulator and UV-transparent material in optics.

Lithium Fluoride, is an inorganic compound with chemical formula LiF. It is a white crystalline powder which is in insoluble in water. It is an odourless substance having a bitter taste which is applicable for various purposes.

LiF Lewis Structure
LiF Lewis Structure

How to draw LiF lewis structure ?

The Lewis dot structures provide a picture of bonding in molecules and ions in terms of the shared pairs of electrons and the octet rule. For sketching the lewis structure of an atom or a molecule only its valence electrons are taken into consideration.

These valence electrons are denoted as certain dots  in its lewis structures. Such  structures drawn by this way are called lewis dot structures.

The lewis structure of lithium fluoride or LiF can be drawn easily. Before that we should understand how the compound is formed. The electronic configuration of  Lithium is (2, 1) and that of the Fluorine is (2,7). Lithium donates its one electron from L shell to the Fluorine atom.

The Fluorine accepts one electron given by the Lithium to form a bond between them. When Li donates its electron it becomes positively charged,  Li+ and when fluorine accepts this electron it becomes negatively charged, F. So the lewis structure of Lithium Fluoride can be drawn as

Since both Lithium and fluorine are in ionic state a square bracket is put over by denoting their charge. The charge denoted is actually the number of electrons lost and gained by lithium and fluorine respectively. Here is +1 for lithium and -1 for fluorine.

LiF Lewis Structure Resonance

Resonance is the movement of delocalised electrons present in an atom of a molecule. A molecule or ion having such electrons is symbolized by some contributing structures. Such structures are called resonance structures.

In the case of Lithium fluoride only one structure is possible.

structure of LiF

LiF Lewis Structure Shape

Lithium donates its electron and fluorine accepts that electron and the compound Lithium fluoride is formed. This is an AB type molecule. So its shape is Linear. LiF has similar structure like NaCl.

Shape of LiF

The unit cell structure of  LiF is cubic unit cell.

LiF lewis structure formal charge

Formal charge is the imaginary charge allotted to an atom  when all its valence electrons are perfectly shared in a chemical bond.

Formal charge of a molecule can be found out by an equation

Formal charge of an atom = No. of valence electrons – No. of dots or electrons –  No.of  bonds  formed.

Valence electrons in LiF

The number of valence electrons present in Li is 1, the electrons present as lone pairs is 0, the number of bonds formed is 1. So the formal charge of Li is

Formal charge of  Lithium = 1-0-1

= 0

The number of valence electrons present in Fluorine  is 7, the electrons present as lone pairs in F is 6, the number of  bonds formed by F  is 1. So the formal charge of F is

Formal charge of  Fluoride = 7-6-1

= 0

The formal charge present in lithium and fluorine in LiF is 0.

LiF lewis structure angle

Bond angle is the angle formed between the 3 bonds when different or same atoms combine together to form a compound. LiF is a linear molecule the angle between the Li-F bond is 1800.

Bond angle of LiF

LiF Lewis Structure Octet Rule

The octet rule states that the  atoms are utmost stable when their valence shells are occupied with eight electrons. It is established on the basis that usually  atoms of  main group elements show this way of participation in chemical bonding.

In accordance with this rule atoms combine together to form chemical bond in such a way that their valence shell should contain only eight electrons.

There found  an exception to octet rule in the case of lithium. Since the first shell of Lithium  can only have 2 electrons it follows duet rule instead of octet rule. The fluorine has 7 valence electrons in its L shell.

When it accepts one electron from Li then its outermost shell is filled with 8 electrons and its octet is fulfilled.

Octet Rule in LiF

LiF Lewis Structure Lone pairs

Lone pair of electrons are the electrons that doesn’t took part in any chemical reaction. The lone pair of electron present  in any molecule is given as .

Lone pair of electron in any atom =  (valence electrons – No. of electrons shared by the atom) /2.

valence electrons in LiF

Lone pair of electron in Li = (1 – 1)/2

= 0

There is no lone pair in Li atom in Lithium fluoride.

Lone pair of electron in F = (7-1)/2

= 3

The lone pair of electrons existing in Fluorine is 3.

LiF Valence electrons

The electrons present in the outermost shell or the valence shell of any atom or ion that can participate in any chemical reaction is called its valence electrons. In the case of Lithium fluoride,  Lithium has only 1 valence electron in its outermost shell .

Fluorine has 7 valence electrons in its outermost shell. Lithium shares its one valence electron to Fluorine makes the ionic bond in between them. So the valence electrons present in Lithium is 1 and that of Fluorine is 7.

LiF Hybridization

Hybridisation is the process of combination of atomic orbital with almost same energy to form a set of new orbitals with same energy. The number of new orbitals formed are equal to the number of atomic orbitals united. The freshly formed orbitals through this process of hybridisation  is called hybrid orbitals. 

But hybridisation is a concept that can be applied in covalent bonded compounds only. Since LiF is an ionic compound, which  is formed by the attraction of opposite charges like a  positive and negative charged ion the concept of  hybridisation is inapplicable in the formation of Lithium Fluoride.

LiF Uses

  1. LiF is a major flux used in the production of enamels, glasses, glazes.
  2. LiF is mainly used for the commercial production of  lithium metal.
  3.  LiF sometimes used as the brazing flux for aluminium in automobiles and dessicant in  drying air streams.
  4. Lithium Fluoride is used for the production of electrolyte in lithium ion battery.
  5. Lithium fluoride is also used in optics,  radiation detectors and in liquid  – fluoride nuclear reactors.

Is LiF ionic or covalent ?

The  bond which is formed by the electrostatic attraction  between a positive and negative ion in a chemical compound is call Ionic bond or electrovalent bond . LiF is formed the attraction of a positively charged Li+ and negatively charged F.

Lithium donates one of its electron to become Li+ and fluorine accepts that to become F, fluoride ion. So LiF is completely an ionic bond.

Is LiF stable ?

Ionic compounds are found to be very stable because they are formed by the strong attraction between the oppositely charged ions. So their bond will be very stable. Therefore  LiF or Lithium fluoride is  stable compound.

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