A CCL4 Lewis structure is a diagram the represents the electron configuration of covalently bonded compounds. Lewis structures are intended to administer a image of the atomic structure and the circulation of electrons in a offered chemical compound.

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Carbon tetrachloride (CCl4) is a covalently external inspection compound created of a central carbon surrounding by 4 chlorine atom in a tetrahedral structure. The Lewis diagram native carbon tetrachloride is:

A continuous atom of carbon has actually 4 lone electron in its outer shell. Chlorine has actually 7 electrons and so is 1 electron quick of completely filling its external shell. Thus, a carbon atom will certainly share each of its 4 external electrons v a single chlorine atom, offering the single carbon atoms and 4 chlorine atom a complete outer covering of electrons. In the result compound, each element has achieved a steady electron construction by having 8 electron in its outer shell.

“We specify organic chemistry as the chemistry of carbon compounds.” — Augustus Kekule

Lewis Structures: The Basics

Lewis structures were very first introduced by the American chemist G.N Lewis in 1916. Because then, they have come to be ubiquitous in high school and college level chemistry process as an easy way to understand chemical bonding.


Lewis structures are meant to represent the atomic and electron structure of a chemistry compound. Each aspect of the compound is represented in the Lewis structure by its chemistry symbol, for this reason H for hydrogen, C because that carbon, O for oxygen, and also so on. The construction of the element’s electron covering is represented by a sample of dots that surround the chemistry symbol. Shared electron pairs are stood for as a solitary line the connects the two bonded elements. Lone pairs of electrons (electrons that do not get involved in chemistry bonding) are stood for as a pair the lone dots next to a chemistry symbol.

How many dots are claimed to be roughly a symbol is determined by the element’s valence number—the variety of electrons in its external shell. Oxygen, for example, has a valence number of 6 since it has actually 6 electron in its outer shell. Most aspects will seek to fill their outer shell entirely and will bond v other facets until their valence number is 8, equivalent to a full outer shell of 8 electrons. The propensity for facets in compounds come arrange us to have actually a complete valence shell of 8 electron is dubbed the octet rule. The lone exemption to the octet dominance is hydrogen. Hydrogen has a complete outer shell with just 2 electrons and also so will kind bonds until it has actually 2 electrons.

“The just difference in between elements and compounds is composed in the claimed impossibility of proving the so-called aspects to it is in compounds.” — Wolfgang Ostwald

So, for example, water (H2O) is a chemical compound created of a single oxygen atom and also two hydrogen atoms. Oxygen has actually 6 valence electrons, and also hydrogen has actually 1 valence electron. Water is formed by an oxygen atom sharing every of its two lone electron in the outer shell with a solitary lone electron in a hydrogen atom. Thus, water’s Lewis structure have the right to be stood for as:


The two solid present connecting the hydrogen atoms to the oxygen atoms represent the mutual pairs of electrons between them and also the 2 pairs that lone dots represent the lone pairs of electrons in the oxygen atom. The valence number of hydrogen is 1 and the valence variety of oxygen is 6, so including those together offers us 1(2)+1(6)=8. So our diagram has actually 8 complete electrons.

Rules because that Making Lewis Structures

Lewis structures are one incredibly helpful tool because that figuring the end the organization of a compound’s components. You can construct a Lewis diagram for a chemical link by complying with these steps:

Step 1. Identify the total number of valence electron in the diagram.

The total number of valence electrons in a Lewis diagram is same to the sum of the valence number of the individual elements that create the compound. Using CCl4 together our example, the total variety of electrons in ours diagram is equal to the sum of the valence number of carbon and also the valence number because that each atom of chlorine. Carbon has actually a valence variety of 4 and each of the four chlorine atom each have actually a valence number of 7. So the total number of electrons in ours diagram of CCl4 should be:

1(4)+4(7) = 32 electrons.

Step 2. Lay out out a skeleton of the compound’s atomic structure.

Next up is to figure out the atomic company of the compound. If the link is diatomic (composed of just two atoms), then this is easy: the atomic framework will simply be the 2 atoms sitting beside each other in a straight line. In a compound with 3 or more atoms, things obtain a bit much more complicated. In most compounds with much more than three atoms, there often tends to be a main atom (or atoms) that shares bonds with multiple atoms. The central atom(s) tends to be the least electronegative facet of the compound.

In ours case, carbon is less electronegative 보다 chlorine, for this reason carbon is the main atom. We have the right to sketch ours diagram through a central carbon atom surrounding by 4 chlorine atoms, choose this:


Step 3. Ar a single bond between each bonded atom pair.

Now that time to to fill in the diagram with electrons. Remember that a solitary line represents one common electron pair. Atoms form covalent compounds by sharing electrons, therefore every atom should share at least one pair of electron with one more atom. Including a single bond to each atom in ours previous diagram gives us:


Since each line counts for two electrons, we have used 8 electrons. That means we still have actually 32−8= 24 electrons left to place in the diagram.

Step 4. Starting with the outer atoms, fill in electron pairs until each outer atom satisfies the octet rule (except hydrogen, which it s okay 2).

Atoms look for to to fill their outer shells v electrons, so they will attempt to do so prior to forming any other bonds. To fill in the diagram through electron pairs (dots) till every terminal atom is surrounded by 8 atoms. Remember that the mutual atom bag count in the direction of the total variety of valence electrons for each atom. Filling in ours diagram offers us:


Since we just placed 12 electron bag we have 24−12(2) = 0 electrons left to place. We inserted them all!

Step 5. If any type of electron pairs remain, put them alongside the central atom until it is full

Once the terminal atoms have actually a full octet, any extra electrons have nowhere else to walk but earlier to the main atom. Place any type of leftover electron pairs about the main atom till the central atom has a full octet. These pairs will certainly exist as lone pairs that remain unbonded.

In ours case, we execute not have any electrons leftover and also every atom in our diagram satisfies the octet rule.

Step 6. If the central atom still does not have a complete outer shell, move existing electron pairs with each other to type a double or triple bond.

If all the terminal atoms have actually a full shell, there are no much more spare electron bag to place, and the central atom still does not have actually a complete outer shell, atoms have actually to acquire a little creative. Present electron bag from the terminal atoms will certainly move and also join shared pairs of electrons to form double or triple bonds. A double bond is basically the terminal atom and central atom sharing 4 electrons, 6 for triple bonds. Twin bonds are represented with a dual line (=) or a triple line (≡).

Following this steps, you can construct a Lewis diagram for a variety of covalently external inspection compounds. In our case, the last Lewis diagram for CCl4 is:


Limitations the Lewis Diagrams

Lewis diagrams are useful and also accurate enough for determining the electron configuration of compounds created out of main team elements, but they have actually some shortcomings. No every chemical compound complies with the specific bonding rules described above. Together with any kind of rule, there room exceptions. Change metals, for instance, frequently don’t follow the octet rule and also instead fill their external shell v 12 electrons. For part compounds, there is no one enough diagram, so the electron construction of those compound are defined as a hybrid of many Lewis diagrams. These space called resonance structures.

“We are favor an atomic structure. We’ve gained a causal human body that’s linked together.” — Frederick Lenz

Lewis diagrams also do not offer much information concerning the 3-dimensional geometric orientation that the atoms, i m sorry is necessary for explaining the polarity and intermolecular bonding actions of compounds. VESPR theory is a chemical modeling method that defines a molecule’s 3-dimensional shape and how that shape arises indigenous the electrostatic repulsion that electron pairs. Electron repel each other so a molecule has tendency to take it a shape that minimizes the repulsion in between electron pairs. This information have the right to be offered to suspect the most likely geometric framework of a provided compound.

Additionally, Lewis diagrams carry out not explain why or how electrons form the bonds lock do. The is a concern that is left as much as molecular orbital concept (MO theory), a mathematical method that describes how electron orbitals incorporate in virtue of the wave-like nature of electrons.

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In summation, Lewis diagrams are a useful and also simple means to define the electron construction of covalently bonded compounds. A Lewis diagram have the right to tell you just how electrons are distributed in a compound and can be offered to predict the distribution. Lewis diagrams are simple to construct and also can it is in made by adhering to a simple set of rules. Lewis frameworks of many compounds developed out of main group facets from periods 2–7 have the right to be built by following the over ruleset.