R 87 b and C133s nuclear magnetic resonance study of the structural properties of mixed RbxCs2−xZnCl4 (x=, 1, and 2) crystals

Abstract

Articles you may be interested inStudy on the paramagnetic relaxation mechanisms by R 87 b nuclear magnetic resonance in Rb 2 MnCl 4 crystals of A 2 B X 4 type Study of the structural phase transitions in RbCuCl 3 and CsCuCl 3 single crystals with the electric-magnetictype interactions using a R 87 b and C 133 s nuclear magnetic resonance spectrometer Structure and photostimulated luminescent properties of Eu-doped M 2 Ba X 4 ( M = Cs , Rb; X = Br , Cl)The structures of mixed Rb x Cs 2−x ZnCl 4 ͑x = 0, 1, and 2͒ single crystals grown by using the slow evaporation method were determined with x-ray diffraction. In addition, the NMR spectra and the spin-lattice relaxation times, T 1 , of the 87 Rb and 133 Cs nuclei of the three crystals were determined by using nuclear magnetic resonance ͑NMR͒ spectroscopy. The spin-lattice relaxation times, T 1 , of the Cs-based compounds are very much longer than those of the Rb-based compounds. The differences between the T 1 values of the Rb and Cs nuclei are due to the difference between their electric quadrupole moments. Further, we analyzed the crystallographic structures of these crystals by considering the occupation probabilities ͑Rb or Cs͒ of the two cationic sites. Our NMR experimental results confirm that there are two crystallographically inequivalent Rb sites, Rb͑1͒ and Rb͑2͒, in Rb 2 ZnCl 4 and two crystallographically inequivalent Cs sites, Cs͑1͒ and Cs͑2͒, in Cs 2 ZnCl 4 . And, only one Rb site and only one Cs site in RbCsZnCl 4 was obtained. The Cs and Rb occupation rates of each of the two available sites, A 1 and A 2 , were determined from the NMR signals.