INFRARED SPECTRA OF SURFACE SPECIES PRODUCED BY REACTIONS OF AMMONIA WITH GERMANIA GEL

Infrared spectra were recorded from 4000 to 500 cm-1 of ammonia sorbed on dehydroxylated germania gel. Extensive dissociation of ammonia occurred, with the formation of Ge-OH groups. The spectra showed that beside physisorbed ammonia, which gave rise to absorptions at 3600-2500, 3420, 3312, and 1610 cm-1 as well as a previously unreported one near 1260 cm-1, at least four other surface species were formed. Bands at 3363, 3267, 1600, 1210, and 700 cm-1 were attributed to ammonia weakly coordinated to surface germanium atoms. Bands at 3467, 3393, and 1535 cm-1 were attributed to a more strongly bonded primary amine which might be the precursor of a secondary amine giving rise to a band at 3397 cm-1. A minor band near 2195 cm-1 was attributed to Ge-H structure.