Here's why:

* Reactants: Magnesium chloride (MgCl₂) and lithium phosphate (Li₃PO₄) are the reactants.

* Products: Magnesium phosphate (Mg₃(PO₄)₂) and lithium chloride (LiCl) are the products.

* Exchange of Ions: The reaction occurs because the cations (positively charged ions) and anions (negatively charged ions) of the reactants switch partners.

There is no single letter representation for this specific type of chemical reaction.

However, you can use the following abbreviations:

* DR: Double Displacement Reaction

* Metathesis: To indicate the specific type of double displacement reaction

Therefore, you could refer to this equation as a DR or metathesis reaction.