LE SPECTRE INFRAROUGE DE L'OZONIDE D'AMMONIUM ET LA STRUCTURE DE L'ION O3−

Abstract

The slow oxidation of solid ammonia by gaseous ozone at low temperature proceeds through an unstable intermediate, ammonium ozonide, after the equation[Formula: see text]The red solid appears on warming around −130 °C, reaches maximum concentration at about −115°, and is all decomposed by −90°. The infrared spectra show, besides the characteristic bands of the NH4+and NO3− ions, two strong bands at 800 and 1 140 cm−1, and two faint ones at 1 260 and 2 053 cm−1 which must belong to the ν2, ν3, ν1and ν1 + ν2 modes of the O3− ion. These frequencies are appreciably higher than the corresponding ones of the ozone molecule, which indicates a stronger bonding in the ozonide ion contrary to most predictions. By analogy with ozone the bond lengths in the ion are estimated to be 1.22 Å and the interbond angle, about 100°.