Carbonic acid on Mars?

For a long time carbonic acid (H2CO3) had defied many efforts for its detection by IR spectroscopic techniques. Recently H2CO3 has been synthesized at low temperature (similar or equal to 10-80 K), and stabilized up to similar or equal to 250 K, by energetic ion irradiation of frozen targets made of H2O:CO2 ice mixtures (Moore and Khanna, Spectrochim. Acta 47, 255-262, 1991; Moore et al., J. Geophys. Res. 96(2), 17,541-17,545, 1991; DelloRusso et al., Geophys. Res. 98(E3), 5505-5510, 1993; Brucato et al., Icarus 1996 (in press)) and by protonation of bicarbonate (Hage el al., J. Am. Chem. Soc. 115, 8427-8431, 1993; J. Chem. Soc. Faraday Trans. 91(17), 2823-2826, 1995). Its IR spectrum has been obtained. A comparison between the IR laboratory spectrum of H2CO3 with some spectra of Mars suggests that carbonic acid could be present on the surface and/or atmosphere of the red planet. Its firm identification requires the acquisition of better astronomical data possibly from space missions (e.g. Mars 96) and would be of primary relevance for both the organic and inorganic chemistry taking place on Mars. Copyright (C) 1996 Elsevier Science Ltd