Zur Kenntnis der Zustandsdiagramme SECl₃/MCl₂ (SE = La, Sm, Gd, Yb; M = Sr, Ba)

Abstract

Mischungen von LaCl3 (SmCl3, GdCl3, YbCl3) mit SrCl2 (BaCl2) wurden differenzthermoanalytisch und röntgenographisch untersucht. In den Zustandsdiagrammen wurden die peritektoid bzw. Peritektisch zerfallenden Verbindungen BaLnCl5, M2InCl7 und Ba3LnCl9 nachgewiesen, die Existenz der Phase Sr4LnCl11 wird vermutet. Eine Mischkristallbildung auf der Basis der Erdalkalihlogenide wurde beobachtet. Sr2SmCl7 und Sr2GdCl7 sind isotyp und wegen der sehr ähnlichen Reflexmuster der Guinier‐Aufnahmen strukturverwandt mit Sm3Cl7. Die Systeme ähneln bei gleichen Radienquotienten der Kationen den Zustandsdiagrammen LnCl7LnCl2. Die Mischungsenthalpien der Systeme LaCl3(GdCl3, YbCl3)SrCl2 wurden calorimetrisch bestimmt. Alle Mischungsenthalpien sind exotherm, die Minima liegen bei etwa 65 Mol‐% SrCl2.

Thermodynamic Assessment of EuCl3–MgCl2 and EuCl3–BaCl2 Systems

“…From EuCl 3 -MgCl 2 to EuCl 3 -BaCl 2 , the values of the mixing enthalpy become more negative. The behavior of the EuCl 3 -MgCl 2 and EuCl 3 -BaCl 2 systems investigated in this study is found to be similar to that of the analogous systems such as LnCl 3 -AECl 2 (Ln = La [15,16], Pr [17], Nd [17], Gd [13,14], Yb [15,16]; AE = Mg, Ca, Sr, Ba).…”

The Alkali-Poor Part of the Pseudoternary Triangle AX/BX2/MX3: Crystal Structures, Properties, and Potentials of (Alkali)/Alkaline-Earth/Rare-Earth Chloride Materials

“…Fluorite Superstructure Derivatives. Phase diagram determinations of the systems BaCl 2 /MCl 3 (M ) La, Sm) 17 revealed incongruently melting phases that were assigned to the compounds Ba 2 LaCl 7 , Ba 2 SmCl 7 , and BaSmCl 5 , although with considerable phase widths. The formation of mixed crystals between the rare-earth chlorides and the high-temperature modification of BaCl 2 (fluorite type of structure) 18 was thought to be responsible for these phase widths.…”

“…The first hints at the existence of “true”, incongruently melting Ba 2 MCl 7 type chlorides came from phase diagram determinations of the systems BaCl 2 /MCl 3 (M = Gd,Yb, Y). , Quite recently, single crystals were grown making use of the Bridgman technique, and the crystal structure was determined for the example of Ba 2 ErCl 7 . The chlorides Ba 2 MCl 7 with M = Gd−Yb,Y were found to be isostructural; for lattice constants, see Table .…”

The Crystal Structure of Ba17Sm10Cl64

“…Blachnik et al (1) examined several BaCl }¸nCl systems by di!erential thermal analysis and identi"ed three phases for the¸n"Sm system. Their composition}temperature phase diagram suggested the formulas of these phases to be BaSmCl , Ba SmCl , and Ba SmCl .…”