RS-3-chloro-2-oxy-propyltrimethylammonium-chloride 1, an important inter- mediate of carnitine and acetylcholine, has been synthesized and resolved by using R,R-tartric acid. Di-(S-3-chloro-2-oxy-propyltrimethylammonium)-R,R-tartrate 2, with optical purity of 81.76%, has been obtained. Compound 2 was characterized by IR spectroscopy, MS, NMR and X-ray diffrac- tion, and it crystallizes in orthorhombic, space group P212121, absolute structure parameter 0.56(8), with cell parameters a = 8.323(2), b = 10.203(2), c = 26.178(5) ? C16H34Cl2N2O8, Mr = 453.272, V = 2223.0(8) ?, Z = 4, Dc = 1.354 g/cm3, m = 0.335 mm-1, F(000) = 968, R = 0.0534 and wR = 0.1274 for 4376 observed reflections (I > 2s(I)). The lattice is composed of two S-3-chloro- 2-oxy-propyltrimethylammonium cations and one R,R-tartrate dianion which are arranged in separate stacks linked via hydrogen bonds. RS-3-chloro-2-oxy-propyltrimethylammonium-chloride 1, an important inter- mediate of carnitine and acetylcholine, has been synthesized and resolved by using R, R-tartric acid. Compound 2 was characterized by IR spectroscopy, MS, NMR and X-ray diffractometry, and it crystallizes in orthorhombic, space group P212121, absolute structure parameter 0.56 (8), with cell parameters a = 8.323 (2), b = 10.203 (2), c = 26.178 (5)? ​​C16H34Cl2N2O8, Mr = 453.272, Dc = 1.354 g / cm3, m = 0.335 mm-1, F (000) = 968, R = 0.0534 and wR = 0.1274 for 4376 observed reflections (I> 2s (I)). The lattice is composed of two S -3-chloro- 2-oxy-propyltrimethylammonium cations and one R, R-tartrate dianion which are arranged in separate stacks linked via hydrogen bonds.