SI2 Lewis Structure: Drawings, Hybridization, Shape, Charges, Pair and Detailed Facts


SI2 Lewis structure provides several facts regarding the formation of the compound and the properties it uses to hold. This article would demonstrate those facts and the theories behind the formation of this structure.

The following facts would be described in this article:

Drawing of SI2 Lewis structure

In the case of drawing the Lewis structure of SI2, the general steps of drawing the Lewis structure must be followed. It is important to identify the total number of valance electron present in the compound. Then choosing the central atom of the compound is the important task to figure out the shape.

In Sulphur diiodide or SI2, Sulphur has 6 valance electrons and Iodine has 7 valance electrons. Two iodine atom take part in the formation of the compound. therefore, the total number of valance electrons possessed by two iodine atoms is (7*2 = 14). SI2 holds (14+6 = 20) valance electrons in total.

Keeping Sulphur in the centre of the compound as only one sulphur atom shares its electrons with two Iodine atoms. Each of the iodine atom shares one electron with the central atom. This completes the structure of the compound. However, Sulphur has lower electronegativity than Iodine and it is smaller as well.

In the above picture, the electrons are being represented with dots. This structure is quite effective to provide the knowledge about valuable fact about the compound.

SI2 Lewis structure shape

SI2 Lewis structure shares the information about the shape of the compound. The geometry of the compound is quite reliable in relating the shape of the compound. These two are quite similar and gives similar idea about the design of the compound.

VSEPR (Valence Shell electron pair repulsion) theory gives broadened knowledge about the shape of the compound. The shape of SI2 has been determined as V-shaped with tetrahedral geometry. 

The bong angle has been found as not to be 180° due to bent shape of the compound. The electronic repulsion between the lone pairs present in the Iodine atoms gives rise to the V shape of the compound.

SI2 Lewis structure formal charges

Formal charges must be calculated by applying the specific formula of formal charges. In this section, we will calculate the formal charges of each of the atom participates in the formation of SI2.

The formula of finding the formal charges of atoms is (valence electrons – nonbonding electrons – ½ bonding electrons).

The formal charge of sulphur is (6 – 4 – (1/2)*2) = 1

The formal charge of each of the iodine atoms is (7 – 6 – (1/2)*1) = 0.5

SI2 Lewis structure lone pairs

According to VSEPR theory, presence of lone pairs highly impact on the shape and geometry of a compound. it is also determined from the Lewis structure of the compound. It is important to identify the numbers of lone pairs present in the compound to recognise the polarity of the bonds as well.

SI2 has lone pairs in its structure. The central atom that is the Sulphur atom does not possess any lone pair but each of the iodine atoms hold 3 lone pairs. These lone pairs effect on the overall polarity of the compound and the shape of the compound.

SI2 hybridization

Hybridization is also denoted by the Lewis structure of the compound. This is highly valuable information as it gives knowledge about the internal structure of the compound. The change in electronic configuration of the elements is shown by representing the internal electronic arrangement of the compound.

SiBr4 Shape and Hybridization from Wikipedia

The hybridization of SI2 is sp3. In the excited state of while sharing electron the restructuration of orbitals of the compound. One electron of sulphur atom replaced from s orbital to the last vacant place of the p orbital. That is why the hybridised state of the compound is sp3.

SI2 Lewis structure resonance

Resonance refers to the concept of alteration of the bonds in any compound. The movement take place among the bonding electrons gives rise to different resonating structure of several compounds, keeping the formula of the compound unchanged.

In SI2 such resonating structure does not exist as the compound holds single bonds with compact composition of electrons. The alteration of the bonds has no need to take place or there is no driving force which gives rise to resonance.

SI2 Lewis structure octet rule

Octet rule is the main reason behind sharing electrons. The elements undergo electron sharing process to fulfil the octet of the. According to octet rule, every periodic element seeks for similar electronic configuration like their nearest noble gas top get ultimate satiety like them.

In SI2, Sulphur tends to adopt two electrons to fulfil its octet and it drives the element undergo electron sharing process with two Iodine atoms.

Each of the Iodine atoms needs to have one more electron to fill octet that is why tow Iodine atom takes two electrons of the Sulphur by giving one electron. This sharing develops the structure of the compound by maintaining octet rule. 

SI2 polar or nonpolar

The effect of lone pairs and the bond angle impacts on the polarity of any compound. the dipole moment possessed by the atoms is the reason for giving rise to the polarity of the compound.

SI2 is polar by nature and the polarised structure take place due to the dipole moment showed by the lone pairs. The bent V-shaped structure of the compound is the reason for polarity. This bent shape does not allow the compound  to cancel out the dipole moment.

Frequently Asked Questions

1:  What is the exact bong angle of SI2?

Answer: The exact bong angle of Sulphur diiodide is 119°. This indicates the bent structure of the compound.

2: Is SI2 ionic or covalent?

Answer: SI2 s purely covalent as electron sharing takes place in the compound instead of complete donation of the electrons from one side.

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