LATTICE VIBRATION-SPECTRA .85. THE SYNERGETIC EFFECT OF COPPER(II), INFRARED-SPECTRA OF CU(OH)(2) AND NA-2[CU(OH)(4)]

The infrared spectra (50 - 4000 cm(-1), 90 and 295 K) of copper hydrox ide Cu(OH)(2) and of sodium hydroxocuprate Na-2[Cu(OH)(4)], and of deu terated samples have been recorded and assigned to the OH stretching m odes, OH librations, and translational modes predicted by group theory . The hydroxide ions are involved in hydrogen bonds of different stren gth, even if the wavenumbers of the respective OK stretches reach the free ion value. This is due to the strong synergetic effect of copper( II). The latter is caused by the Jahn-Teller behaviour of Cu2+ which e nables very short Cu-O distances of < 185 pm. Hydroxy copper compounds which do not display hydrogen bonds as, for example, talc containing copper are very scarce.