Phosphorous

Phosphorous does not react with dilute non-oxidizing acids.

At room temperature, phosphorous spontanteously ignites in air, forming phosphorous pentoxide (actually tetraphosphorous decaoxide, P₄O₁₀).

P₄(s) + 5 O₂(g) P₄O₁₀(s)


Under controlled conditions (75% O₂, 25% N₂, 50 °C, 90 mm Hg), a mixture is formed, containing phosphorous trioxide (actually tetraphosphorous hexaoxide, P₄O₆).

P₄(s) + 3 O₂(g) P₄O₆(s)

Phosphorous reacts with hot concentrated solutions of sodium hydroxide, forming sodium hypophosphite and phosphine [4].

P₄(s) + 3 OH⁻(aq) + 3 H₂O(l) 3 H₂PO₂⁻(aq) + PH₃(g)

Phosphorous reacts with excess F₂ forming phosphorous(V)fluoride [4].

2 P(s) + 5 F₂(g) 2 PF₅(s)

with excess phosphorous [4], the reaction is

2 P(s) + 3 F₂(g) 2 PF₃(s)
PF₃(s) + F₂(g) PF₅(s)


Phosphorous reacts with excess Cl₂ forming phosphorous(V)chloride [4].

2 P(s) + 5 Cl₂(g) 2 PCl₅(s)

with excess phosphorous [4], the reaction is

2 P(s) + 3 Cl₂(g) 2 PCl₃(s)
PCl₃(s) + Cl₂(g) PCl₅(s)


Phosphorous reacts with excess Br₂ forming phosphorous(V)chloride [4].

2 P(s) + 5 Br₂(l) 2 PBr₅(s)

with excess phosphorous [4], the reaction is

2 P(s) + 3 Br₂(l) 2 PBr₃(s)
PBr₃(s) + Br₂(l) PBr₅(s)


Phosphorous does not react with I₂ [4].

Cadmium reacts with P at elevated temperatures in an exoterm process forming Cd₃P₂ and CdP₂ [5].

4 Cd(s) + P₄(s) Cd₃P₂(s) + CdP₂(s)


Sodium reacts with phosphorous forming sodium phosphide [4]:

12 Na(s) + P₄(s) 4 Na₄P(s)