Journal of Molecular Structure, 293 (1993) 105-108 Elsevier Science Publishers B.V.. Amsterdam 105 INFRARED SPECTRA OF RUBIDIUM DIAQUATETRACHLORONICKELATE(I1) zyxwvutsrqp Bojan Soptrajanov, Viktor Stefov and Marina Ivanovska Institut za hemija, PMF, Univerzitet “Kiril i Metodij” P.O. Box 162, 91001 Skopje, Macedonia The infrared spectra of Rbz[NiC14(H20)21 as well as those of a series of its partially deuterated analogues were recorded at room and at liquid-nitrogen temperature (RT and LNT respectively). The combined results from the analysis of these spectra were used to assign the observed infrared bands. 1. INTRODUCTION Continuing our work on the infrared spectra of Rbz [MnC14 (H2O)zl and of its cesium analogue [1,21, we deci- ded to study the infrared spectra of the isostructural Rbz [NiC14 (H20)2 I and of a series of its partially de- uterated analogues. The infrared and Raman spectra of protiated Rbz [NiC14 (H20)2] have al- ready been studied (at 15 K) by Shankle and Bates 131 who listed the frequencies and assignment of the observed bands in the region from 3700 to 50 cm-l. The deuterated analogues were not studied, however, and thus the opportunity to adequa- tely assign the bands which are due to the internal and, especially, the external vibrations of the water mo- lecules on the basis of their beha- viour on partial deuteration [1,2] was missed. It was shown (141 as quoted in [3]) that Rbz [NiC14 (H20)2 1 crystallizes ip the triclinic system (space group PI, 2 = 1). Only one type of water molecules, lying on general positions, are pre- sent in the structure. The water molecules are trigonally coordinated and surrounded by a manganese(2t) ion and two chlorine atoms acting as proton-acceptors. 2. EXPERIMENTAL The studied compound was prepared according to literature methods [31. The deuterated analogues were prepa- red in a similar manner but using as solvents HzO/DzO mixtures of approp- riate composition. The infrared spectra were recorded, at room and at liquid-nitrogen tem- perature (RT and LNT), on a Perkin- Elmer 580 infrared spectrophotometer provided with a VLT-2 (RIIC, London) variable temperature cell. Nujoll and fluorolube mulls and RbCl pellets were used. 3. RESULTSAND DISCUSSION The RT and LNT infrared spectra of Rbz [NiC14 (H20)2 1 recorded between 4000 and 350 cm-l are presented in 0022-2860/93/$06.00 0 1993 Elsevier Science Publishers B.V. All rights reserved.