کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1625181 1516426 2008 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Lanthanide(III) halides: Thermodynamic properties and their correlation with crystal structure
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد فلزات و آلیاژها
پیش نمایش صفحه اول مقاله
Lanthanide(III) halides: Thermodynamic properties and their correlation with crystal structure
چکیده انگلیسی

Temperatures and enthalpies of phase transitions of 17 lanthanide(III) halides determined experimentally are reported. Correlations were made between temperature of fusion of lanthanide(III) halides, on the one hand, and enthalpy of fusion, on the other, versus atomic number of lanthanide. According to this classification, the lanthanide(III) halides split into groups, as also do the corresponding crystal structures. A correlation between the crystal structure of lanthanide(III) halides and their respective entropy of fusion (or entropy of fusion + entropy of solid–solid phase transition) was inferred from the aforementioned features. Fusion in those halides with hexagonal, UCl3-type and orthorhombic, PuBr3-type, structures entails an entropy of fusion change (or entropy of fusion + entropy of solid–solid phase transition change) by 50 ± 4 J mol−1 K−1. The homologous entropy change within the group of halides having the rhomboedric, FeCl3-type, structure, is smaller and equals 40 ± 4 J mol−1 K−1. Halides with monoclinic, AlCl3-type, crystal structure constitute a third group associated to an even smaller entropy change upon fusion, only 31 ± 4 J mol−1 K−1. The halides with lower entropies of fusion also have a lower S1300 K − S298 K indicating either a higher degree of order in the liquid or a higher entropy in the solid at room temperatures.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 450, Issues 1–2, 14 February 2008, Pages 167–174
نویسندگان
, ,