As can be seen, in the overall reaction we have in the reactants like in the second reaction and in the products. The is in the first reaction but as a reactant so we need to reverse that reaction:
A molecular structure is a shape of a molecule, a three-dimensional shape or configuration of a molecule that is dependent on the preferred spatial orientation of covalent bonds to atoms having two or more partners. Attached is the diagram for the molecular structure of So42 .