salts of the acid m sup u2295 h sup u2295 of formula i were all amorphous surprisingly the dierythromycin salt and the dicholine salt have a distinct crystalline structure providing the compounds with enhanced stability in addition to their broad antimicrobial spectrum to prepare the novel salt of the present invention first the free acid of formula i m sup u2295 h sup u2295 may be prepared as described in the copending application ser no 695 775 filed jan 28 1985 now u s pat no 4 618 061 the acid m sup u2295 h sup u2295 of formula i is thereafter treated with erythromycin or choline hydroxide to form the antibiotics of the present invention i e the dierythromycin salt m sup u2295 erythromycin h sup u2295 or the dicholine salt m sup u2295 hoch 2 ch 2 n sup u2295 ch 3 3 of the acid m sup u2295 h sup u2295 of formula i alternatively the starting material can be a salt of the acid m sup u2295 h sup u2295 of formula i as prepared by the procedures described in u s pat nos 4 533 660 or 4 337 197 or the above cited pending application ser no 695 775 filed jan 28 1985 now u s pat no 4 618 061 or one or the other of the salts of the present invention the cationic portion of the salt can be removed by.