Crystal forms of the double molybdates of potassium with samarium, europium, and gadolinium KLn (MoO/sub 4/)/sub 2/
The polymorphism of KLn (MoO/sub 4/)/sub 2/ (Ln=Sm, Eu, or Gd) is studied by differential thermal analysis and high-temperature x-ray diffraction. Common to all these compounds are crystal forms resembling monoclinic ..cap alpha..-KBi(MoO/sub 4/)/sub 2/ and orthorhombic KY(MoO/sub 4/)/sub 2/. The KEu and KGd molybdates are stable in the triclinic form (..cap alpha..-KEu(MoO/sub 4/)/sub 2/ type), at temperatures below 930 and 860/sup 0/C, respectively, and just before melting in a form belonging to an unknown structure, which on rapid cooling suffers a transformation in the metastable state assuming the form of pseudotetragonal (orthorhombic) RbPr (MoO/sub 4/)/sub 2/. The KSm molybdate is isostructural at high temperatures (approximately-greater-than 960/sup 0/C) with tetragonal scheelite. The compounds melt at 970--1000/sup 0/C. (AIP)
- Research Organization:
- Institute of Inorganic Chemistry, Siberian Branch, Academy of Sciences of the USSR
- OSTI ID:
- 7343449
- Journal Information:
- Sov. Phys. - Crystallogr. (Engl. Transl.); (United States), Journal Name: Sov. Phys. - Crystallogr. (Engl. Transl.); (United States) Vol. 21:2; ISSN SPHCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360602* -- Other Materials-- Structure & Phase Studies
ALKALI METAL COMPOUNDS
COHERENT SCATTERING
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DIFFERENTIAL THERMAL ANALYSIS
DIFFRACTION
EUROPIUM COMPOUNDS
GADOLINIUM COMPOUNDS
MOLYBDATES
MOLYBDENUM COMPOUNDS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
POTASSIUM COMPOUNDS
RARE EARTH COMPOUNDS
SAMARIUM COMPOUNDS
SCATTERING
TEMPERATURE DEPENDENCE
THERMAL ANALYSIS
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION