SOF4 Lewis Structure: Drawings, Hybridization, Shape, Charges, Pair and Detailed Facts

SOF4 has a chemical name sulphur tetra- fluoride oxide. SOF4 can also be written as F4OS.

SOF4 has some synonyms like sulphur tetra- fluoride, thionyl tetra- fluoride and tetrafluoro(oxo)-lambda6-sulfane. SOF4 has molecular weight 124.06. The IUPAC name of SOF4 is tetrafluoro(oxo)-λ6-sulfane. SOF4 molecule is consists of total three elements i.e. one sulphur, one oxygen and four fluorine atoms. At this juncture, we are studying about SOF4 lewis structure and detailed facts.

How to draw lewis structure for SOF4?

Any lewis structure is drawn by remembering some points as counting valence electrons, selection of least electronegative atom at central position, bonding within all atoms, lone pair electron count, complete octet of all atoms, calculate formal charge, etc.

In SOF4 lewis structure, the sulphur atom comes under 16th periodic table group, oxygen atom comes under 16th periodic table group and fluorine atom comes under 7th periodic table group having 6, 6 and 7 valence electrons in their outer shell orbital respectively. Also the S atom has electronegativity 2.58, O atom has electronegativity 3.44 and F atom has electronegativity 3.98.

So, the sulphur atom possesses central position of SOF4 molecule due to its lowest electronegativity. All the other atoms F and O get bonded to central sulphur atom. SOF4 lewis structure is drawn by counting valence electrons and bonding create in all atoms, then count lone pair electrons and apply octet role with calculation of formal charge.

sof4 lewis structure
SOF4 lewis structure

SOF4 lewis structure octet rule

Octet means the presence of 8 electrons in any atom. The SOF4 lewis structure consists of sulphur, oxygen and fluorine atoms having 6, 6 and 7 electrons respectively. Therefore, total valence electrons in SOF4 molecule is 6 (S) + 6 (O) + 7 x 4 (F) = 40. Hence SOF4 molecule has total forty valence electrons present on it. Also if we calculate total electron pairs of SOF4 then 40 / 2 = 20, we have 20 electron pairs.

So, we have Out of these 40 valence electrons 10 valence electrons get engaged in bonding and being bond pair electrons. Therefore, we are now left with remaining 30 valence electrons for more distribution or sharing in SOF4 molecule. Now we have to put all the 30 valence electrons on outer oxygen and fluorine atoms to complete its octet. If there is 10 bonding electrons then each F and O atom contains more 6 non- bonding electrons.

Each bonding electron pair contains two electrons, hence two bonding and six non- bonding electrons; total eight electrons are present on each F and O atom. So, the outer four fluorine and one oxygen atoms contains eight electrons so they have complete octets and the central sulphur atom has total ten bonding electrons, so sulphur atom has extended octet in SOF4 lewis structure.

SOF4 molecule showing complete octet of all outer atoms and extended octet of central sulphur atom

SOF4 lewis structure lone pairs

SOF4 lewis structure has total 40 valence electrons, out of which 10 electrons are bonding electrons and the remaining 30 electrons are non- bonding electrons present on one oxygen and four fluorine atoms in SOF4 molecule. If we make a bonding within all the outer four fluorine and one oxygen atoms with central sulphur atom, so each S and O atom have 6 non- bonding electrons present on it.

These 30 non- bonding electrons present on outer F and O atoms get paired so we get 15 electron pairs which are lone electron pairs. So, each fluorine and oxygen atom has 6 non- bonding electrons means three lone electron pairs. Therefore, total lone electron pairs on SOF4 leis structure is 3 x 4 (F) + 3 (O) = 15. SOF4 lewis structure has total fifteen lone electron pairs.

SOF4 lewis structure formal charges

Calculation for formal charge can be done through the following formula:

Formal charge = (valence electrons – non-bonding electrons – ½ bonding electrons)

Calculation of formal charges of SOF4 lewis structure can be done by calculating the formal charge of each atoms present on it i.e. sulphur, oxygen and fluorine atoms formal charge calculation as follows.

Sulphur atom: Valence electrons on sulphur atom = 06

                       Non- bonding electrons on sulphur atom = 00

                       Bonding electrons on sulphur atom = 10 (2 electrons in single bond)

Formal charge on sulphur atom is = (06 – 00 – 10/2) = +1

So, the sulphur atom of SOF4 lewis structure has plus one (+1) formal charge.

Oxygen atom: Oxygen atom have Valence electrons = 06

                        Oxygen atom have non- bonding electrons = 06

                          Oxygen atom have Bonding electrons = 02 (2 electrons in single bond)

Formal charge on oxygen atom is = (6 – 6 – 2/2) = -1

So, the oxygen atom of SOF4 lewis structure has minus one (-1) formal charge.

Fluorine atom: Valence electrons on fluorine atom = 07

                        Non- bonding electrons on fluorine atom = 06

                        Bonding electrons on fluorine atom = 2 (2 electrons in single bond)

Formal charge on fluorine atom is = (07 – 06 – 2/2) = 0

So, the fluorine atom of SOF4 lewis structure has zero formal charge.

SOF4 lewis structure resonance

Resonance structure of any molecule can only is possible when the structure or molecules have multiple bonds means double or triple bond, also there should be presence of lone electron pairs and formal charges on the structure or molecule. Then only we can draw the resonance structure of any molecule by transfer of electrons and changing the bonding within the molecule.

The SOF4 molecule can show two lewis structures. In SOF4 lewis structure, there are five single covalent within central sulphur atom and four F and one O atoms. In these case the formal charge present on central sulphur atom is plus one (+1) and the formal charge present on oxygen atom is minus one (-1) rather four fluorine atoms have zero formal charge. Hence SOF4 molecule with single covalent bonds having higher formal charge on S and O atom making SOF4 molecule unstable in nature.

So, we have to minimize the formal charge on sulphur and oxygen atoms by moving one lone electron pair of oxygen atom inside to make a double bond (S=O). After the formation of double bond between S and O atom, the formal charge on sulphur and oxygen atom becomes zero and the four fluorine atoms already has zero formal charge. Thus by making double bond within sulphur and oxygen atom the formal charge gets minimize and SOF4 lewis structure becomes more stable in nature.

SOF4 lewis structure showing two resonance structures

SOF4 lewis structure shape

On the basis of VSEPR theory, the molecule consists of one central metal atom attached with five outer bonding atoms followed the generic formula AX5. A = central atom, X = bonded atoms to central metal atom. The molecules with AX5 generic formula having molecular geometry and electron geometry is trigonal bipyrimidal.

In SOF4 lewis structure, the central sulphur atom is also connected with total five outer atoms i.e. four fluorine atoms and one oxygen atom. Thus, SOF4 molecule is following the VSEPR theory generic formula AX5. So, SOF4 molecule has molecular geometry and electron geometry trigonal bipyrimidal. Hence, the shape of SOF4 lewis structure is trigonal bipyrimidal.

Trigonal bipyrimidal shape of SOF4 lewis structure

SOF4 hybridization

As per the VSEPR theory SOF4 molecule comes under the generic formula AX5 and having molecular geometry and electronic geometry trigonal bipyrimidal, thus SOF4 molecule have trigonal bipyrimadal shape. The VSEPR theory says, the molecule with AX5 generic formula having central atom bonded with five outer atoms comes under sp3d hybridization.

So, the SOF4 lewis structure has sp3d hybridization according to the VSEPR theory. Also the bond angles with these molecules are 90 degree and 120 degree. In SOF4 lewis structure, we have seen that the trigonal bipyrimidal shape of SOF4 molecule having two Sulphur fluorine covalent bonds (S-F) are at 90 degree angles and the angle between fluorine sulphur fluorine bonds are 120 degree and also the bond angle between fluorine sulphur oxygen bonds are 120 degree.

SOF4 polar or nonpolar

In a molecule or chemical compound parting of electric charge cause electric dipole is known as polarity. Polar bonds are present in polar molecules as there is the difference in bonded atoms or elements electronegativity. If two or more polar bonds present in polar molecule then t must has an asymmetric geometry then the bond dipoles are not cancelling each other.

Polar molecules act with each other by hydrogen bonds or intermolecular dipole- dipole forces. Polar molecules contain net dipole moment due to the presence of opposite charges i.e. it has partial negative and partial positive charge present in polar bonds which are asymmetrically arranged.

In SOF4 lewis structure, it has a trigonal bipyrimidal geometry with asymmetrical charge distribution around the central sulphur atom i.e. the central sulphur atom has five asymmetrical electron charge densities around it. Hence, SOF4 molecule is polar in nature.

SOF4 uses

Sulphur tetra- fluoride oxide is used to prepare thionyl tetra- fluoride. It is also used to prepared various chemicals like sulphur di- fluoride, hydrofluoric acid, sulphurofluorioridic acid. It is also used in the preparation of mercurous fluoride, fluoride ions and fluorosulphate ions.


Sulphur tetra- fluoride oxide (SOF4) is consists of one sulphur, one oxygen and four fluorine atom. It has total 40 valence electrons and 14 lone pair electrons. SOF4 lewis structure is following AX5 generic formula and has trigonal pyramidal shape, sp3d hybridization and has 90 degree and 120 degree bond angles. SOF4 molecule is polar in nature.

Dr. Shruti Ramteke

Hello everyone I am Dr. Shruti M Ramteke, i did my Ph.D in chemistry. I have five years of teaching experience for 11-12 standard, B,Sc and MSc in chemistry subject. I have published total five research articles during Ph.D on my research work and i have fellowship from UGC for my Ph.D. My Masters with specilization Inorganic chemistry and my graduation with chemistry, zoology and environmental science subjects. thank You

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