Acta Phys. -Chim. Sin. ›› 2001, Vol. 17 ›› Issue (10): 956-960.doi: 10.3866/PKU.WHXB20011019

• Note • Previous Articles    

Determination of Standard Enthalpies of Formation of Rare Earth (RE=Pr,Er) with L-Proline [RE2(L-Pro)6(H2O)4](ClO4)6 Complexes

Wu Xin-Ming;Liu Yi;Qu Song-Sheng;Zhang Da-Shun;Liu Ping;Wang Chun-Yan   

  1. College of Chemistry and Molecular Science,Wuhan University,Wuhan 430072;Department of Chemistry and Chemical Engineering,Changde Teacher′s University,Changde 415000
  • Received:2001-04-02 Revised:2001-06-28 Published:2001-10-15
  • Contact: Qu Song-Sheng

Abstract: Crystals of two complex compounds of rareearth perchlorate with Lproline,[RE2(LPro)6(H2O)4](ClO4)6(RE=Pr,Er),were synthesized.Their structures were characterized using TG,DTA,chemical analytic method and comparing with literatures,and the purity is determined as 99.24% and 98.20%,respectively.For the calculation of chemical reaction heat,solution heat of the [2RE(NO3)3•6H2O+6LPro+6NaClO4•H2O] and the {[RE2(LPro)6(H2O)4](ClO4)6+6NaNO3} were firstly measured in 2 mol•L1 HCl solvent with an isoperibel reaction calorimeter,respectively.The standard enthalpy of formation of the two crystals were calculated by chemical reaction heat and a designed thermochemical cycle at 298.15 K.The following reaction enthalpy and standard enthalpy of formation were obtained:   RE=Pr:ΔrHm=-63.904 kJ•mol-1;RE=Er:ΔrHm=- 91.017 kJ•mol-1;   ΔfHm([Pr2(LPro)6(H2O)4](ClO4)6,s,298.15 K)=-6 594.78 kJ•mol-1;   ΔfHm([Er2(LPro)6(H2O)4](ClO4)6,s,298.15 K)=-6 532.87 kJ•mol-1.

Key words: Perchlorate, L-Proline, [RE2(L-Pro)6(H2O)4](ClO4)6(RE=Pr,Er)