β -TCP (β-Ca₃(PO₄)₂) is a rare naturally occurring mineral, yet it is the second most abundant mineral in bones. By supporting magnesium ion in its structure, when obtained by synthesis, it mimics its natural form. Therefore, it can be used as a material for medical and dental applications, since magnesium promotes better cell adhesion to bone substrate. This study aimed to obtain the β-TCP/Mg²⁺ phase from dolomite through acid dissolution and precipitation reactions, as well as to investigate the structural changes caused by the addition of magnesium in the β-TCP phase. The β-TCP/Mg²⁺ synthesis was effective in the production of a potential biomaterial based on calcium phosphates with magnesium in its structure. Rietveld's analyses enabled the identification of two phosphate-rich phases, Ca₇Mg₉(Ca,Mg)₂(PO₄)₁₂ and Ca_2.66Mg_0.34(PO₄)₂, with β -TCP obtained as the majority phase. It was also possible to observe, by obtaining high-resolution electronic density maps, changes in the β-TCP phase structure caused by the replacement of the magnesium atom in the Ca5 crystallographic site along with possible substitutions to a lesser extent in the remaining calcium sites. The material obtained can have a potential use as biomaterial.