Preparation, crystal structure and thermodynamic properties of [Mg(H2O)6](NTO)2·2H2O

[Mg(H2O)6](NTO)2·2H2O was prepared by adding magnesium carbonate hydroxide to the aqueous solution of 3-nitro-1,2,4-triazol-5-one (NTO). The single crystal structure has been determined by a four-circle X-ray diffractometer. The compound is monoclinic with space group C2/c and unit-cell parameters a=2.3101(3) nm, b=0.6472(1) nm, c=1.4118(3) nm and β=124.05(1)°. From measurements of the enthalpy of solution in water at 298.15 K, the standard molar enthalpy of formation, lattice energy and lattice enthalpy have been determined as −(3015.38±4.2) kJ mol−1, −2680.7 and −2653.2 kJ mol−1.