Structural and Magnetic Properties of [(CH₃)₃NH] CuCl₃2H₂O


The crystal structure at room temperature and the low-temperature heat capacity and magnetic susceptibilities of single crystals of [(CH3)3 NH]CuCl3 2H2O are reported. The monoclinic crystals belong to the space group P21c with a=7.479(10), b=7.864(11), c=16.730(23), =91.98(3)°, and Z=4. The structure consists of chains of edge-sharing [CuCl4(OH2)2] octahedra running along the a axis. Each copper atom is coordinated in a square plane by two water molecules and two chlorine atoms, with two more chlorine atoms at a longer distance. The susceptibility data can be fitted adequately between 1.5 and 20°K by a CurieWeiss law [ga=2.080.01, gb=2.020.01; gc=2.110.01; a=(0.380.03)°K, b=(0.360.03)°K, c=(0.410.03)°K], but the susceptibility parallel to the chain can be better fitted as an Ising linear chain. Measurements perpendicular to the chain are not as well fitted by the Ising model. The heat capacity, which consists primarily of a lattice contribution above 3°K, begins to rise as the temperature falls below 3°K, but long-range order does not set in above 1°K, the lowest temperature attained in this work. Both Ising and Heisenberg linear-chain models fit the low-temperature data with |Jk| <1°K. The results are compared with those reported for the compounds CuCl2 2H2O and CuCl2 2NC5H5. © 1972 The American Physical Society.



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© 1972 American Physical Society (APS), All rights reserved.