NS2 Lewis Structure& Characteristics: 11 Complete Facts

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NS2 molecule with IUPAC nomenclature as Dithiooxoamonium is a salt with molecular weight of 78.136 g/mol. Let us study more facts about NS2.

NS2 lewis molecule is an odd electron species due to the presence of one unpaired electron in the system. The salt appears to be stable even in the presence of unpaired electron.

NS2 molecule has been studied due to its odd electron nature. Let us discuss more facts about NS2, lewis structure, bond angle, valence electrons calculation etc.

How to draw NS2 lewis structure?

Lewis structure is an electronic representation of the skeletal structure of a polyatomic molecule that gives idea about its characteristics. Let us draw NS2 lewis structure.

Counting the total valence electrons

The ground state electronic configurations of N and S are [He]2s22p3 and [Ne]3s23p4. The electrons in 2s, 2p, 3s and 3p are the outermost valence shell electrons that contributes to construction of NS2 lewis structure. This makes a total of 17 valence electrons available.

Choosing the central atom

N is chosen as the central atom. A more electropositive atom would have lesser tendency to keep its electrons closer to its nuclei and form more bonds. S has electronegativity (X) of 2.58, higher than N with X = 3.04 but N is still selected as the central atom.

Drawing the skeletal structure

This step happens in accord with octet rule, which should have at least 8 electrons in its surroundings. The first step involves putting two electrons between two sets of N-S. 2 extra electrons are added between one of the N-S sets. This forms an odd electron species.

Simplifying the electron pairs

There are 3 electron pairs out of which one N-S set has two electrons pairs and other N-S set has one electron pair. This accounts for a total of 6 valence electrons out of 17 electrons.

Assigning the remaining valence electrons

The remaining 11 electrons that do not participate in bond formation are assigned as the lone pair of electrons. 3 lone pairs reside on one S atom, 2 lone pairs on another S atom and one electron on N. Since all other lone pairs are paired except the one on N, it is called an odd electron species.

ns2 lewis lambda
NS2 lewis structure

NS2 lewis structure resonance

Resonance is the mesomerism phenomenon observed in covalent molecule that has delocalized pi electron cloud. Let us check if NS2 has resonance.

NS2 lewis structure has two resonance structures. In one structure, N has four covalent bonds which happens by S sharing one electron from one of its 3 lone pairs and one from N. In other resonance structure, N has 3 covalent bonds. In both the cases, it is an odd electron species.

The two resonance structures involving electron delocalization over N-S makes the molecule a stable one.

ns2 lambda resonance
Resonance structure of NS2 lewis structure

NS2 lewis structure formal charge

Formal charge is the imaginary hypothetical charge acquired by an atom in a molecule assuming all the electrons are shared equally. Let us discuss in details.

Formal charge of NS2 is zero which is calculated using formal charge = (Number of valence electrons in a free atom of the element) – (Number of unshared electrons on the atom) – (Number of bonds to the atom)

  • Formal charge of N = 5-1-3 = +1
  • Formal charge of S1 = 6-6-1 = -1
  • Formal charge of S2 = 6-4-2 = 0
  • N has +1 formal charge and one of the S has -1 charge.
  • This makes the overall charge equal to zero and it is neutral.
  • S2 is double bonded and S1 is single bonded to N.

NS2 lewis structure octet rule

Octet rule is a general rule adapted for drawing a lewis structure model according to which every atom should have at least 8 electrons in its shell. Let us discuss below.

NS2 lewis structure does not follow octet rule. The molecule is an odd electron species. N atom does not fulfill the octet rule by 1 electron. It has 7 electrons in its octet. Both the S atoms follow octet rule by having 8 electrons in its octet. The molecule despite not following octet rule is stable.

It is not necessary for a molecule to always follow octet rule in order to be stable.

NS2 lewis structure lone pairs

Lone pairs are the electron pairs that do not take part in any chemical bond formation. Let us calculate lone pairs for NS2 lewis structure.

NS2 lewis structure has a total of 5 lone pairs of electrons. S1 has a total of 3 lone pairs of electrons out of 5. S1 has 2 lone pairs of electrons. NS2 is an odd electron species so a single unpaired electron lies on N, which cannot be counted as lone pairs.

In another resonance structure of NS2 , a total of 4 lone pairs of electrons are available. Each S atom has 2 lone pairs of electrons each. In this case, a single unpaired electron is present on S.

NS2 valence electrons

Valence electrons are the loosely bounded outermost electrons to the nuclei that can participate in any chemical bond formation. Let us calculate valence electrons for NS2 .

NS2 lewis structure has a total of 17 valence electrons. Outer shell electronic configuration of N and S are 2s22p3 and 3s23p4. The outermost electrons in 2s, 3s, 2p and 3p contributes to the total valence shell electrons. There are two S atoms so the total valence electrons from both are 12 plus 5 from N.

NS2 hybridization

Hybridization is a phenomenon of mixing atomic orbitals higher in energy to obtain hybridized atomic orbitals. Let us discuss in details.

NS2 has sp2 hybridization in one structure and sp in other form. In one form which have 3 covalent bonds, NS2 has sp2 hybridization due to the presence of one double bond between N-S. In other form, NS2 has sp hybridization with 2 double bonds between both N-S sets.

NS2 lewis structure shape

Shape of a molecule is the overall structure assumed by it without considering the total lone pairs. Let us discuss further.

The shape of NS2 lewis structure is bent in one form and linear in other. It is bent when there is only one double bond present in one of the two N-S as it obeys sp2 hybridization. NS2 is linear in shape when the central atom N is sp hybridized.

NS2 lewis structure
NS2 lewis structure shape

NS2 bond angle

Bond angle is the angle between a central atom and any two adjacent atoms attached to the same central atom in a polyatomic molecule. Let us discus in details.

Bond angle of NS2 is approximately 120o in sp2 hybridized bent shape of NS2 molecule. It has minimum repulsion between the bond pairs. In sp hybridization, NS2 lewis structure adopts a linear shape with 1800 as the bond angle. Both the forms are equally stable.

Is NS2 polar or nonpolar?

Non polar molecules are those whose dipole moments vectors cancel out giving zero or almost zero dipole. Let us check if NS2 is a polar or nonpolar molecule.

NS2 is a polar molecule. It is polar in both the forms: Linear and Bent shape. In both the forms, the dipole moments vectors from the central atom to the end atoms do not completely cancel each other.

Why and How NS2 is polar?

Polarity of a molecule can be identified using dipole moment vectors of each bonds. Let us discuss in details.

NS2 is polar as the bonds are not symmetrical or equivalent leading to non-cancellation of dipole moment’s vectors. The double bonds in either bent or linear form has greater dipole moment vectors than the single bond vector.

Is NS2 ionic or covalent?

Ionic molecules have greater electronegativity difference that can be identified from the charge separation. Let us check if NS2 is ionic or covalent.

NS2 is a covalent molecule with partial ionic character. This is because the electronegativity difference between N and S is not that great to make it a completely ionic molecule. However, during electron delocalization from N to S, partial charges are generated to show partial ionic character.

N and S have electronegativity difference of 0.5, and according to Fajan’s rule, it is nearly a covalent molecule.

Conclusion

NS2 lewis structure is a covalent polar molecule that stays as an odd electron species in both the bent and linear forms. The hybridization is different in both the forms and stable.

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