DEUTERIUM QUADRUPOLAR INTERACTION IN THE M2CUX4.2D2O COMPOUNDS

The deuterium quadrupolar interactions in the M2CuX4.2D2O compounds have been detected for 4 K < T < 300 K. The observed EFG tensor at 300 K differs strongly from that at low temperatures as a result of fast reorientations of the water molecules along their bisecting axes. A relation has been found between νQ(D) and the O-D distance that is valid for all O-D...Y hydrogen bounds. From the observed νQ(D) values the charge across the hydrogen bridge has been calculated. In the (ND4)2CuX4.2D2O compounds two different orientations for the ND4 ions have been determined at low temperature which results in a lower symmetry for these ammonium compounds than for the alkali compounds. © 1979.