Two experimental techniques were used to elucidate how acetonitrile molecules are bound to the title complex, [Cr(acac)(3)] : (i) measurement of NMR longitudinal relaxation rates of the dipolar nuclei of the solvent (H-1, methyl-C-13, and cyano-C-13 of CH3CN) in the presence of [Cr(acac)(3)], which is a paramagnetic complex, and (ii) X-ray diffraction measurements on acetonitrile solutions of [Cr(acac)(3)] and [Ru(acac)(3)] using an isostructural substitution method. The results of both methods are in harmony with each other. Four acetonitrile molecules are found within about 6 x 10(-10) m from the chromium atom. They are in the hollows on the peripheral surface of the three acetylacetonato ligands, one or two in the hollows along the C-3 axis of the complex, and two or three in the hollows along the C-2 axes. They are oriented with the methyl ends inward : the angle between the molecular axis of acetonitrile and the vector from the chromium atom to the methyl carbon of acetonitrile was about 100 degrees.