Hydrogen bonding: Part IX. Low temperature infrared spectra of H4O2F22− and H6O42− cluster anions in tetramethylammonium fluoride and hyd

At 10–20 K the broad room temperature IR bands of the hydrogen bonded cluster anions in tetramethylammonium fluoride and hydroxide monohydrates and monohydrates-d_n are resolved into a number of components. The band patterns are consonant with distortion of formally tetrahedral H₄F₂O₂^2? and H₆O₄^2? ions of T_d point group to C2v and S₄, respectively in a C_4h⁵ unit cell isomorphous with tetramethylammonium hexafluorosilicate. A lattice mode has been identified for each monohydrate.