Thermochemistry of the ternary complex Nd(Et n dtc) 3 (phen)

The ternary solid complex has been synthesized with sodium diethyldithiocarbamate (NaEt 2 dtc·3H 2 O), 1,10‐phenanthroline ( o ‐phen·H 2 O) and hydrated neodymium chloride in absolute ethanol. The title complex was identified as the general formula of Nd(Et 2 dtc) 3 (phen) by chemical and elemental analyses. IR spectrum of the complex showed that the Nd 3+ coordinated with six sulfur atoms of three NaEt 2 dtc and two nitrogen atoms of o ‐phen. It was assumed that the coordination number of Nd 3+ is eight. The enthalpy change of liquid‐phase reaction of formation, Δ r H   Θ m(1), was determined as (‐12.274±0.050) kJ·mol −1 at 298.15 K by a microcalorimeter, the enthalpy change of the solid‐phase reaction of formation, Δ r H   Θ m(s), was calculated as (149.069±0.314) kJ·mol −1 on the basis of a thermochemical cycle. The thermodynamics of reaction of formation was studied by changing the temperature of liquid‐phase reaction. The constant‐volume combustion energy of the complex, Δ c U , was determined as (‐18674.22±8.33) kI·mol −1 by a precise rotating‐bomb calorimeter at 298.15 K. Its standard enthalpy of combustion, Δ c H   Θ m , and standard enthalpy of formation, Δ f H   Θ m , were calculated as (‐18693.43 ± 8.33) kJ·mol −1 and (‐47.03 ± 9.17) kJ·mol −1 , respectively.