Problem of polymorphism and fusion of lanthanide trifluorides. I. The influence of oxygen on phase transition temperatures

Journal Article · Sun Feb 01 04:00:00 EST 1976 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(76)90220-6· OSTI ID:7290272

Sobolev, B P ^[1]; Fedorov, P P; Shteynberg, D B; Sinitsyn, B V; Shakhkalamian, G S

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1. Inst. of Crystallography, Moscow

The details of using thermal analysis (TA) in the investigation of lanthanide trifluorides are examined. By examining the literature on the problem of phase transitions in LnF/sub 3/ (Ln = lanthanum and the lanthanides), it is established that the basic reason for disagreement among the data is, in most cases, lack of control of pyrohydrolysis of LnF/sub 3/. For the first time, parts of the phase diagrams of the LnF/sub 3/--Ln/sub 2/O/sub 3/ systems (Ln = Gd, Tb, Ho, Er, and Y) have been studied with TA methods. Phases LnF/sub 3-2x/O/sub x/ where 0 less than or equal to x less than or equal to 0.2, which were not known earlier, are discovered. According to the type of interaction of LnF/sub 3/ with the corresponding Ln/sub 2/O/sub 3/, the trifluoride series is broken down into several groups corresponding to the structural type in which the LnF/sub 3/ crystallizes. The parts of the phase diagrams of the LnF/sub 3/--Ln/sub 2/O/sub 3/ systems that were studied permit us to explain the reasons for contradictions in existing data on the temperatures of phase transformations in LnF/sub 3/.

• OSTI ID: 7290272
• Journal Information: J. Solid State Chem.; (United States), Journal Name: J. Solid State Chem.; (United States) Vol. 17:1-2; ISSN JSSCB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
CHALCOGENIDES
CRYOGENIC FLUIDS
DIAGRAMS
ELEMENTS
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
MELTING
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
RARE EARTH COMPOUNDS
THERMAL ANALYSIS