The infrared spectra of a series of metal saccharinates (those of Na, Mg, Mn Fe, Co; Ni, Zn, Cd, Pb as well as mercury(II) saccharinate and chloromercury(II) saccharinate) were studied in the region of the antisymmetric and symmetric SO₂ stretching vibrations [v_as(SO₂) and v_s(SO₂) hereafter]. The results concerning the number of bands attributable to the abovementioned vibrations, their frequencies and intensities were correlated with the crystallographically determined type of metal-to-ligand bonding, on the one hand, and the number of the structurally different SO₂ groups, on the other. It was shown that, irrespective on whether the sulphonyl oxygen atoms do or do not participate in bonding to the metal atom and/or in hydrogen bonding and irrespective on the type of the metal-to-saccharin bond (from covalent to purely ionic), the frequencies of both v_as(SO₂) and v_s(SO₂) modes are lower for the metal saccharinates than for saccharin itself, the effect being more pronounced in the case of the v_as(SO₂) bands. As expected, the appearance of the spectra in the SO₂ stretching regions is rather strongly dependent on the values of the O-S-O angles. Thus, two rather different types of O-S-O angles exist in the structure of the covalently bonded saccharinate of mercury and of the ionic lead saccharinate (the values of these angles are 118.7 and 111.8 ° and 120.4 and 111.8 ° respectively) and two pairs of v_as(SO₂) and v_s(SO₂) bands are present in the spectra of these two compounds. On the other hand, the existence of only one type of SO₂ groups in the saccharinates of Mn and ClHg or the presence of SO₂ groups with very close O-S-O angles in the saccharinates of Na and Mg is manifested by the appearance of only a single pair of intense v_as(SO₂) and v_s(SO₂) bands in their spectra.