Manganese mercury thiocyanate-bis(dimethyl sulfoxide) MnHg(SCN)(4)(C2H6OS)(2) (MMTD) single crystals of optical quality have been grown from solution by the slow temperature-lowering method. The X-ray powder diffraction (XRPD) spectroscopy of MMTD crystal was performed at room temperature. The morphology of the crystal was indexed. The thermal decomposition process is characterized by differential scanning calorimetry (DSC). The specific heat of the crystal is 699.5 J mol(-1) K-1 at 300 K. The thermal expansion coefficient (TEC) along the a-, b- and c-axis is alpha(1) = 5.33 x 10(-5), alpha(2) = 4.51 x 10(-5) and alpha(3) = 3.10 x 10(-5) /K, respectively. All the TECs are positive and interpreted on the basis of crystal structure. (C) 2002 Elsevier Science B.V. All rights reserved.