Phenylphosphine (C6H5PH2\text{C}_6\text{H}_5\text{PH}_2C6H5PH2) can be represented as ArPH2\text{ArPH}_2ArPH2 and its protonated form, the phenylphosphonium ion ([C6H5PH3]+[\text{C}_6\text{H}_5\text{PH}_3]^+[C6H5PH3]+), can be represented as [ArPH3]+[\text{ArPH}_3]^+[ArPH3]+.
Describe or draw the three-dimensional shapes around the phosphorus atom in ArPH2\text{ArPH}_2ArPH2 and in [ArPH3]+[\text{ArPH}_3]^+[ArPH3]+. Include any lone pairs on the phosphorus atom.
State whether the H−P−H\text{H}-\text{P}-\text{H}H−P−H bond angle in ArPH2\text{ArPH}_2ArPH2 is greater than, the same as, or smaller than that in [ArPH3]+[\text{ArPH}_3]^+[ArPH3]+.
Explain your answer in terms of electron pair repulsion theory.
