Browsing by Author "Tench, A J"

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    Infra-Red Study of the Adsorption of Ammonia on MgO: Part 1.—The Dehydrated Surface
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (2), 1972) Tench, A J; Giles, D
    The adsorption of ammonia gas has been studied on dehydrated MgO. The symmetrical bending vibration v2 of ammonia is considerably perturbed by the presence of the surface and a doubling of this band is observed at low concentrations of ammonia. Models for the nature of the adsorbed species are discussed and it is concluded that the ammonia molecule is probably hydrogen-bonded to an oxide ion in the surface. There is no evidence for Bronsted or Lewis acid sites on the surface.
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    Infra-Red Study of the Adsorption of Ammonia on MgO: Part 2.—The Hydrated Surface
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (2), 1972) Tench, A J
    Ammonia is weakly adsorbed on hydrated MgO by hydrogen-bonding of the nitrogen to hydroxyl groups exposed on the surface and a strong band at 3045 cm-1 is attributed to surface hydroxyl groups perturbed by the adsorbed ammonia. A rapid isotopic exchange is evident when ND3 is adsorbed; a band ascribed to the symmetric bending frequency is observed at 1137 cm-1 for adsorbed NH3, and two bands at 945 and 860 cm-1 observed when ND3 is adsorbed arc assigned to NHD2 and NDj respectively. All traces of ammonia can be removed by evacuation at room temperature.