Crystal structures of sodium dimethyl sulfosuccinate and sodium diethyl sulfosuccinate

Article abstract of DOI:10.1016/S0022-2860(98)00378-0

The crystal structures of sodium dimethyl sulfosuccinate and sodium diethyl sulfosuccinate have been determined by the single crystal X-ray diffraction method. Sodium dimethyl sulfosuccinate (SDMS, C₆H₉O₇SNa·H₂O, Mr = 266.20) crystallizes in a triclinic space group P1 with unit cell dimensions a = 5.5971 (8), b = 6.5388 (5), c = 15.267 (2) A, α = 77.855 (8), β = 85.90 (1), γ = 84.95 (1)°. The crystal of sodium diethyl sulfosuccinate (SDES, C₈H₁₃O₇SNa·3H₂O, Mr = 330.29) has a monoclinic space group C2/c with unit cell dimensions a = 34.754 (3), b = 6.0322 (7), c = 15.0777 (9) A, β = 104.385 (7)°. In the SDMS and SDES crystals, the Na⁺ ion, which is coordinated to six oxygen atoms, forms an octahedral structure. For SDMS, the Na⁺ ion is coordinated to four oxygen atoms of SO₃/^- groups and to the two oxygen atoms of water molecules of hydration. For SDES, the Na⁺ ion is coordinated to the oxygen atom of the β-chain C=O group, one of the SO₃/^- oxygen atoms and four oxygen atoms of hydrating water molecules. It was found that splitting of the C=O stretch band caused by the Na...O=C coordination occurs in the IR and Raman spectra of SDES.