Specific heat of Ni(ClO4)26H2O between 2 and 17 K

A specific heat investigation of nickel perchlorate hexahydrate was performed between 2 and 17 K. Lattice vibration and magnetic contributions were separated. The lattice term obeys a Debye αT³ law, with $\text{α = 4.04 × 10}{}^{\mathrm{?3}}\text{J}\text{K}{}^4$ mol. The magnetic contribution comes from the splitting of the ground state triplet of the Ni²⁺ ions, by axial and rhombic crystal field distortions, which can be explained by a Schottky specific heat with D = 1.72 KandE = 0.06 K.