H2s Lewis Structure, Characteristics: 43 Complete Quick Facts

H2S is a colorless gas, carries pungent smell like rotten egg, mainly used for producing Sulfuric acid, Sulfur, creating pesticides also used in nuclear power plant.

The article describes the H2S lewis structure with other properties it has which can be describe from the hybridization of the structure and the ‘d’ orbital that Sulfur carries.

How to draw H2s lewis structure?

With the atomic symbols of Sulfur (S) and Hydrogen (H), the H2S lewis structure shows the outer orbit electrons distribution, spreading around the particular atom and sharing electron cloud with neighbor atom in GeCl4 molecule.

Count the total valence electrons:

In modern Periodic table the Sulfur atom is in group 16 with electronic distribution in 3s and 3p orbital, that is [Ne] 3s2 3p4 and Hydrogen atom contains only one electron its outer orbital as a group 1 element, so total eight loosely bonded valence electrons are there to form covalent bond.

Draw the skeletal of H2S lewis structure:

As Hydrogen atom can’t coordinate with more than one atom so Sulfur become central atom and two Hydrogen atoms are written on the opposite sides. This H2S lewis structure follows the Octet rule with electron sharing and also has zero formal charge.

h2s lewis structure
H2S lewis structure

H2s lewis structure resonance

H2S lewis structure can’t form resonating structure as the ligand has no ‘d’ orbital for delocalization of electrons and also ligand atom has no unshared electron which can delocalize to the vacant 3d orbital of central atom Sulfur.

In spite of having 3d vacant orbital as a 3rd period element canonical structure can’t form as the only one electron of Hydrogen atom is already involved in the covalent bonding.  

H2s lewis structure shape

According to VBT theory molecular geometry and shape are two slightly different things if the central atom has unshared electrons, which can be clearly understood by the hybridization of orbital of the central atom of a covalent molecule.

From the intermixing of orbital of the Sulfur atom in the H2S lewis structure generate hybrid orbital which is sp3, the geometry of the molecule should be tetrahedral type as for the AX2E2 where X stands for Hydrogen atom and E for electron lone pair.

But for the steric repulsion between lone pairs in the structure which Sulfur carries make the geometry disturbed from its original form and the angle between the bonding orbitals decreases forms a bent ‘V’ like shape.

h2s lewis structure
H2S lewis acid structure shape

H2s lewis structure formal charge

Formal charge of H2S lewis structure is zero, calculated to check stability of the canonical form with help of total outer shell electron, bonding electron cloud and unshared electron and assuming that the bonding electron are distributed equally.

In the molecule only Sulfur atom has four electrons that not take part in bonding, so formal charge for the central atom Sulfur is = {6- 4- (4/2)} = 0 and without any nonbonding electron formal charge for the each Hydrogen atom is = {1- 0- (2/2)} = 0.

As both the constituent atom has zero formal charge, this particular canonical form of H2S also has zero formal charge which makes the structure energetically stable one.

H2s lewis structure angle

In the H2S lewis structure, the intermixing 3s, 3p orbital form sp3 hybridized orbital, so the covalent bond angle should be 109.5̊ but it is lowered to 92.1̊ by the steric repulsion between dense two non bonding electron pair of ‘S’.

For decreasing the bond angle (angle between the overlapping bonding orbital), the angle between the two nonbonding electron pairs increases for stabilizing the electron dot structure from the repulsion of dense lone electron pairs.

The angle between the bonding electron pair and non bonding electron pair is also decreased to adjust the new ‘V’ like bent structure.

H2s lewis structure octet rule

Last filled orbit, specific energy wave function must have eight electrons for satisfy the energy of stability of the particular canonical form, known as Octet rule which naturally can be seen in inactive inert gas molecules.

From the Periodic table we can say Sulfur needs two more electrons to cover the 3p orbital where Hydrogen needs only one electron to stabilize its configuration like Helium, so both shares electron cloud and cover up their last filled shells.

H2s lewis structure lone pairs

Lone pair are those valence electron pair with higher electronic concentration which does not take part in the bond formation and causes steric repulsion with bonding electron cloud and disturbs the geometry of a molecule.

From the hybridization we see the Sulfur has two electrons in 3s and another two in 3p which don’t take part in bond formation with Hydrogen, remaining as lone pairs over Sulfur atom where the one electron of Hydrogen involves in bonding, so no lone pair over Hydrogen.

H2s valence electrons

The last filled shell containing electrons are valence electrons which are far apart from nucleus so loosely bound by nuclear attraction and if ‘d’ orbital is there they become more energetically available for excitation in the chemical reaction.

Being a ‘p’ block element of group 16 in 3rd Period, Sulfur contains two electrons in 3s and four in 3p whereas each of the two Hydrogen atoms has one electron in their 1s orbital, so total eight loosely bounded electrons are energetically available for bonding.

H2s hybridization

Hybridization is the concept where not equivalent atomic orbitals intermix to give same energy hybrid orbital, the concept is used for central atom of covalent molecule for understanding the better orbital overlapping in the molecule.

As a ‘p’ block atom the central atom Sulfur has six outer shell electrons in 3s and 3p, the orbitals mixes up, creates new hybrid orbital ‘sp3’ with new shape and energy than previous, which carry 25% ‘s’ character and 75% ‘p’ character and overlap with H2 1s orbital.

From this hybridization we can say that the covalent nature is greater in the molecule as it contains more ‘p’ character and electro-negativity of Sulfur is also not much because the greater the hybrid orbital carry the ‘S’ character greater its electro- negative nature become.

H2s solubility

Solubility of H2S in solvent is determined by the concentration of H2s at the equilibrium of the reaction, as a covalent compound of weak dipole- dipole interaction it is gas at room temperature making low solubility in water.

It can’t make any intermolecular Hydrogen bonding, also be the reason of slight solubility.

Is H2s soluble in water?

H2S solubility in water is 4 g/dm at 20̊ C so it is slightly soluble in water which can be described by the dipole moment present in the molecule.

In spite of having non polar bonding for low difference in electro-negativity H2S lewis structure is polar for presence of the dipole moment which causes delta charge separation and as a result H2S slightly soluble in polar solvent like H2O.

Is H2s an electrolyte?

Electrolytes are the compound generally made by metal and non-metal or semiconductor as they can fully ionized in solution to carry the electronic charge make them good electrolytes.

As both Sulfur and Hydrogen are non- metal so they can’t fully oxidized so can’t  be goof electrolyte, it only slightly dissociates in water.

Is H2s acidic or basic?

H2S acts as a bronsted acid as it forms (HS-) by donating a hydrogen ion (H+) when it slightly soluble in water, hence it is weak acid in nature by donating one proton, another proton releasing is quite energy requiring process.

With pKa 7.0 it can turns a blue litmus paper in red color by the formation of bisulfide (HS-) indicates its acidic nature as (SH-) can be stabilized for the bulky size of the Sulfur which accelerate the (H+) ion releasing process.

Is h2s a strong acid?

An acid which completely dissociates in its components ions are known as strong acid but after one proton donation H2S forms (HS-) ion and the dissociation constant for 2nd step of the reaction is too small, makes it a weak acid.

Is H2s polar or nonpolar?

In the H2S lewis structure, electro-negativity of ‘S’ is 2.58 and that of ‘H’ is 2.20 on the basis of Pauling scale, makes bond electron cloud pulling capability difference by 0.38, which is quietly less, results a non-polar bond but creates some charge separation denoted as delta (δ).

The delta charge separation creates a dipole moment with certain direction in the structure. The structure also contains lone pairs which also have some vector direction of polarity and overall for bent structure both can’t cancel out and H2S become a polar molecule.

image 247
polarity of H2S lewis structure

Is H2s a lewis acid or base?

H2S lewis structure contains sulfur atom which has vacant 3d orbital to accept electron pair from donor to act as lewis acid and also the structure contains nonbonding electron pairs can do nucleophilic attack to act as lewis base.

In water it accept electron in its vacant 3d orbital to form hydronium ion (H3O+), becomes a lewis acid (accept electron pair from donor).

In presence of strong acid like H2SO4 it donate electron to form new S-H bond results in H3S+ formation which indicates the lewis base (can transfer electron pair to acceptor) character of H2S lewis structure.

Is H2s linear?

H2S can’t be linear although it can form a linear H-S-H configuration but this is distorted as Central atom Sulfur contains nonbonding two electrons in 3s and two in 3p which causes steric repulsion and according to VSEPR theory causes bent form.

According to this theory as lone pairs only concentrate over parent atom, having more electronic density it causes greater inter lone pair repulsion than lone pair- bond pair and the bond angle decreases causes bent molecule.

Is H2s paramagnetic or diamagnetic?

The magnetic property of H2S lewis structure can be explained by the electronic arrangement of the central atom Sulfur, after bonding with Hydrogen 1s electron there is no unpaired electron remains in the sp3 orbital of ‘S’.

As all the electrons are paired up so the electrons with opposite spin can cancel out each other’s magnetic field, so H2S lewis structure become diamagnetic in nature but for paramagnetic there will be at least one unpaired electron.

H2s boiling point

Boiling point is dependent on the environment pressure, in a constant pressure at which temperature the vapour pressure of liquid and atmospheric pressure of the environment of liquid come in equilibrium that is called boiling point of that temp.

The measuring boiling point of H2S lewis structure is (-60̊ C), the low value is because of the covalent nature of the molecule so the attraction between the atoms are lesser than ionic compounds, results in easily bond breaking, also there is no Hydrogen bonding.

H2s bond angle

The angle between covalent bonding which is formed by hybridized orbital overlapping, is 92.1 which is measured depending on hybridization of outer orbital of central atom, Sulfur has four such electrons which not participate in bonding.

In the H2S lewis structure, the 4s and 4p orbital of Sulfur atom intermixes, form sp3 hybridized orbital, so the bond angle should be 109.5̊ but it is lowered by the steric repulsion between non bonding electron pair of ‘S’ as they have more electronic density.

Is h2s corrosive?

H2S is corrosive in nature but it alone with water can’t cause much damage. H2S can react with water and gives (H+) ion as a weak acid, so it the source of (H+) ions and act as a catalyst in absorption of (H+) ion on steel causes cracking in steel.

In the reaction Sulfide is formed so the corrosion can cause discolor of the copper or silver as it can form a thin black cover, in case of silver it produces Silver sulfide (black).

Does H2S have conductivity?

H2S lewis structure become metallic conductor type which can transfer electricity above a pressure of 90 giga-pascal, if it is cooled down and set the temperature below the critical temperature the high pressure state of H2S shows super conductivity.

Is h2s coloured?

H2S is a colorless gas compound but for its reducing agent nature the color can be changed with long time.

Normally the compound with transition metal element which contains ‘d’ orbital shows color for as there electronic transition can be took part and the color it shows is the complementary color related to the energy which releases in the electron emission process.

Is h2s odorless?

H2S has a specific rotten egg type smell where compounds with Sulfur have some pungent smell but only it has specific characteristic odor, smelling which is not harmful for human but causes some uneasiness in health.

Is h2s capable of dipole dipole interactions?

Dipole moment of a covalent bond has magnitude with a specific vector direction which causes a charge separation between delta positive and delta negative which can be seen in the H2S lewis structure, for the electro negativity difference of atoms.

When two molecules of H2S approach each other there dipole- dipole interaction occurs between the delta positive Hydrogen atom of one molecule and delta negative Sulfur of another molecule which is a weak interaction but stronger than London interaction.

Is h2s permanent dipole?

The dipole moment which is produced in the H2S lewis structure is permanent as it is based on the difference of the electron pulling capacity of its constituent atoms, not by induced effect from the environment.

If the dipole moment of the molecule is produced by the induction effect of environment then it can be normalized by controlling the environment but here in H2S lewis structure the dipole moment is permanent with value of 0.97 D.

Is h2s electron deficient?

Hydrides of Sulfur is not electron deficient as central atom Sulfur belongs from group 16 which makes proper covalent bonding with Hydrogen atoms by sharing the electron cloud, following the Octet rule properly.

Generally group 13 elements produces the covalent hydride compounds where the central atom outer shell is not filled up with eight electrons so they become electron deficient molecules.

Is h2s oxidizing agent?

H2S can’t act as an oxidizing agent as (-2) is the oxidation state of H2S lewis structure and H2S can’t produce lower oxidation state by accepting electron from a donor atom.

The Sulfur atom of other molecule which has (+) oxidation state in a molecule and can lower the oxidation state by accepting electron from donor  can act as an oxidizing agent  like H2SO4 where the oxidation state of Sulfur is (+6).

Is h2s fully oxidized?

Fully oxidized means here the releasing of (H+) ion in highest amount, but being a weak acid one H2S lewis structure can’t release two of its hydrogen atoms freely (high 2nd dissociation constant) though it is a diprotic acid.

It slightly dissociates in water to give (SH-) as a conjugate base as (H+) ion so H2S lewis structure is not fully oxidized always.

Is h2s reducing agent?

For having ‘d’ orbital Sulfur atom of H2S molecule can shows different oxidation states and can forms molecules with various coordination number  where in H2S it has (-2) oxidation state.

This Oxidation state (hypothetical charge of an atom in a molecule) of Sulfur is lowest among all other Oxidation states so it can’t be lowered more so H2S act as a reducing agent as it can donate electron pair in redox reaction.

Does h2s form hydrogen bonds?

In spite of having dipole- dipole interaction there Hydrogen bonding can’t be formed between the H2S lewis structures, which can be seen only molecule having high electro negativity atom like ‘F’, ‘O’ or ‘N’ attached with any electro-positive atom.

Sulfur is quite less electro-negative (2.58) with respect to these electro- negative atoms so H-X bond (X=S) will not be that much polar that the Sulfur can induce dipole moment to Hydrogen atom of another H2S molecule and form any Hydrogen bonding.

Is h2s heavier than air?

H2S is slightly heavier than air as it is 1.19 times denser than air, so we can find that H2S gas gathers in the low lying spaces for the property.

Is h2s london dispersion?

As a hetero atomic molecule, with electro negativity difference between the constituent atom the H2S lewis structure possess some permanent dipole moment in the covalent bond of the molecule so have dipole-dipole interaction present.

For non polar symmetric molecules where is no dipole moment, there can be seen the London dispersion force between the molecules which is the weakest attraction force causes temporary dipole moment in molecules which is not for polar asymmetric H2S.

Is h2s monoprotic diprotic or triprotic?

H2S is a diprotic acid as it can release two Hydrogen ions (H+) in the solution though the 2nd dissociation constant is two low making the 2nd step slow.

In the 1st step of reaction (H+) is released with (HS-) where from one more (H+) ion can be released with precipitation of (S2-) ion, where the 1st dissociation constant is relatively higher.

Is h2s more acidic than h2o?

H2S is more acidic than water (H2O) which can be explained by two following reasons, one is the size of Sulfur which has ‘d’ orbital to accept electron pair and other reason is the strength of O-H bond is greater than S-H bond strength.

Being a group 16 member in period 3 makes Sulfur molecule more bulky than Oxygen which is in period 2 makes the conjugate base (SH-) more stable than (OH-), also ‘S’ has the diffused ‘d’ orbital which can bear nucleophilic attack and release (H+) ion in solvent.

In X-H (X= O / S) bond breaking the dissociation energy of bond plays an important role which is lower in case of H2S than H2O as the electro-negativity of Oxygen is greater to pull bonding electron cloud towards itself to fast and can release hydrogen ion.

But for higher electro-negativity the Oxygen of water (H2O) make intermolecular bond with Hydrogen atom of one molecule to Oxygen atom of another molecule which is very strong, requires more energy to dissociates result H2S stronger acid than H2O. 

Is h2s more acidic than hbr?

No, H2S is less acidic (pKa = 7) than HBr (pKa = (-9)) which can be explained by electro-negativity difference between Bromine (Br) that is 2.96 and Sulfur (S) that is 2.58.

With greater electro negativity of an atom it can pull the bond electron cloud towards itself more easily so there will be a shift in electron cloud density makes easy for bond dissociation which not required energy too much.

Electronegative halogen atom Bromine can pull the Br-H electron cloud greater than in case of Sulfur in S-H bond and also Bromine is not as electro-negative as Oxyhen so the intermolecular hydrogen bonding is not so strong like H2O make HBr stronger acid than H2S.

Is h2s metal or nonmetal?

From Periodic table we know H2S lewis structure contains non metal elements like Sulfur and Hydrogen form group 16 and group 1 respectively, results in the forming of non metal molecule with combination between them.

As non metal molecule the boiling point of H2S is very low even it is in gas form at room temperature as there is no strong electrostatic attraction between atoms of the molecule, in spite they have weak dipole- dipole interaction between molecules.

Is h2s positive or negative?

To satisfy the octet rule the atoms of H2S lewis structure shares their valence electron cloud makes the molecule covalent in nature so it is neutral in nature without any positive or negative charge.

But as Sulfur and Hydrogen has some difference in electro-negativity (capacity of pulling the electron pair), dipole moment arise in the covalent bond which is 0.97 D, for this a slightly partial charge separation occurs in the molecule that is ‘S’ (δ+) and ‘H’ (δ-).

Is h2s pyramidal?

As per the Hybridization of the central Sulfur atom which occupying two non bonding electrons makes the geometry disturbed and form bent ‘V’ like not pyramidal which can be seen in AX3E type molecule with one lone pair.

The geometry of this type molecule should be tetrahedral but the bonding skeletal looks like pyramidal as the lone pair posses over one bonding direction in the tetrahedral geometry.

Is h2s symmetrical or asymmetrical?

H2S is a asymmetric molecule for which we can see that the dipole moments are not cancel out each other  and the H2S lewis structure overall has a net dipole moment which causes polarity of the molecule in spite of having non polar bonds.

If this was a symmetrical molecule the vector directions of dipole moment can cancel out each other and H2S become non polar in nature which is not possible the electron pairs that Sulfur has which not participate in bonding with Hydrogen atoms.

Is h2s volatile?

H2S is much volatile than Sulfur’s upper periodic element Oxygen’s Hydride (water, H2O), even H2S lewis structure is in gas form in normal room temperature but water is in liquid form in room temperature.

This phenomenon can be described by the electro negativity of central atom and Hydrogen bond formation as a consequence of it. As there is no possibility for H2S lewis structure to form Hydrogen bonding they can be easily energized and stay in gas form.

If inter molecular Hydrogen bonding will there the molecules are tightly bonded with each other  and for transfer them in gas form, high temperature will be required causes high boiling point.


Being a covalent and slightly polar molecule it shows its properties sometimes different as central atom of H2S lewis structure has the vacant 3d orbital which can easily accept electron pairs from donor atom.

Also Read: