$$\begin{gathered} {\mathrm{P}}_4 + {\mathrm{SOCl}}_2\to \mathrm{X} + \mathrm{Y} + \mathrm{Z} \\ {\mathrm{P}}_{4 } + {\mathrm{SO}}_2{\mathrm{Cl}}_2\to \mathrm{M} + \mathrm{Y} \end{gathered}$$

Compound Y is :

P₄ reacts with SOCl₂ to form PCl₃, SO₂, and S₂Cl₂.

${\mathrm{P}}_4+8{\mathrm{SOCl}}_2\to \underset{\mathrm{X}}{4{\mathrm{PCl}}_3}+\underset{\mathrm{Y}}{4{\mathrm{SO}}_2}+\underset{\mathrm{Z}}{2{\mathrm{S}}_2{\mathrm{Cl}}_2}$

P₄ reacts with SO₂Cl₂ to form PCl₅ and SO₂.

${\mathrm{P}}_{4 }+10{\mathrm{SO}}_2{\mathrm{Cl}}_2\to 4\underset{\mathrm{M}}{{\mathrm{PCI}}_5}+\underset{\mathrm{Y}}{10{\mathrm{SO}}_2}$