A crystallized solid of metallophosphate type, referred to by the designation IM-8 can be partially substituted by an element X and optionally by an element Y. The metallophosphate is of a chemical composition, expressed on an anhydrous basis is defined by the formula R_s(G_gP_pX_xY_y)O₂ in which G represents one or more trivalent elements, R represents one or more organic compounds, X represents one or more divalent elements, and Y represents one or more tetravalent elements, and in which s0.2, g0.5, p0.5, x0.4 and y0.3 with g+p+x+y=1. The crystallized solid is useful as an adsorbent.