Barium sulfate(BaSO4) is used to help doctors examine the esophagus, stomach, and intestine using x-rays or computed tomography. It works by coating the esophagus, stomach, or intestine with a material that is not absorbed into the body so that diseased or damaged areas can be clearly seen by x-ray examination or CT scan. It is non-combustible and non-toxic. Emits toxic sulfur oxides when heated to decomposition.Reacts with reducing agents such as potassium, phosphorus or aluminum.

Lewis Structure

Lewis Structure of ions/compounds can show whether the octet of an atom is completed or not. It can also be useful in speculating the stability of molecules.

Step-by-Step Drawing the lewis structure of BaSO4

Step 1: Count total valence electrons

Barium (Ba): Group ⅡA, 2 valence electrons;

Sulfur (S): Group ⅥA, 6 valence electrons;

Oxygen (O): Group ⅥA, 4 O atoms → 4×6=24 valence electrons;

Charge correction:

loses 2 electrons to form and gains 2 extra electrons (total charge = -2);

Total valence electrons for SO42?:2+6+24=32 valence electrons;

Step 2: Draw skeletal structure

Place Sulfur (S) as the central atom (less electronegative than O).

Connect 4 Oxygen atoms to the central S atom with single covalent bonds.Each single bond uses 2 electrons: 4×2=8 electrons used.Remaining electrons: 32?8=24 electrons.

Step 3: Add lone pairs to outer atoms (Oxygen)

Each O atom needs 6 more electrons (3 lone pairs) to satisfy the octet rule.4 O atoms: 4×6=24 electrons.All remaining electrons are fully used; every oxygen now has a complete octet.

Step 4: Check octet for central Sulfur

Central S atom has 4 bonding pairs (8 electrons) → octet satisfied.Sulfur is in Period 3, so it can also form resonance structures with S=O double bonds (expanded octet, common for sulfate).

Step 5: Label formal charges & ionic separation

Formal charge formula:

Formal Charge (FC)=Valence e??(Lone pair e?+21Bonding e?)

For single-bonded O: FC=6?(6+1)=?1

For central S: FC=6?(0+4)=+2

Net charge of SO42?: +2+4(?1)=?2 (matches ion charge)

Step 6: Resonance structures (Supplement)

Barium sulfate(BaSO4) has 4 equivalent resonance structures: one of the four S–O single bonds is replaced with an S=O double bond in each resonance form. Double-bonded oxygen has a formal charge of 0, which stabilizes the ion.