Structure and stability of the low-temperature modification compounds Cs[sub 3]LnCl[sub 6] (Ln = La-Gd)
- Univ. Gh Kassel (Germany)
- Fa, Stoe, Darmstadt (Germany)
The crystal structure of the low-temperature modification of Cs[sub 3]LaCl[sub 6] has been determined from X-ray powder diffraction data by the Rietveld method. The monoclinic lattice with a = 27.286(5) [angstrom]; b = 8.291(1) [angstrom]; c = 13.305(2) [angstrom]; [beta] = 99.64(1)[degrees] belongs to the Cs[sub 3]BiCl[sub 6]-type (space group C2/c). All other compounds Cs[sub 3]LnCl[sub 6] (Ln = Gd) and the analogous Rb-compounds are isotypic. Emf measurements in a galvanic cell for solid electrolytes for the reactions CsCl + Cs[sub 2]LnCl[sub 5] = Cs[sub 3]LnCl[sub 6] reveal that the compounds with Ln = La,Ce,Pr,Nd are formed with a loss of lattice enthalpy, compensated by a considerable gain in entropy; they therefore are stable only at temperatures higher than O K. The compounds with Ln = Sm,Eu,Dg are formed with a gain in lattice enthalpy and are stable at T = OK, too. This difference is attributed to the different crystal structures of the neighboring compounds Cs[sub 2]LnCl[sub 5]: they crystallize with the K[sub 2]PrCl[sub 5]-structure (CN = 7 for Ln[sup 3+]) for the compounds with Ln = La-Nd, while the other compounds belong to the Cs[sub 2]DyCl[sub 5]-type with octahedral surroundings for the Ln[sup 3+] ions.
- OSTI ID:
- 7072220
- Journal Information:
- Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 107:1; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360602 -- Other Materials-- Structure & Phase Studies
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKALI METAL COMPOUNDS
CERIUM CHLORIDES
CERIUM COMPOUNDS
CESIUM CHLORIDES
CESIUM COMPOUNDS
CHLORIDES
CHLORINE COMPOUNDS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
EUROPIUM CHLORIDES
EUROPIUM COMPOUNDS
GADOLINIUM CHLORIDES
GADOLINIUM COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
LANTHANUM CHLORIDES
LANTHANUM COMPOUNDS
LATTICE PARAMETERS
MONOCLINIC LATTICES
NEODYMIUM CHLORIDES
NEODYMIUM COMPOUNDS
PRASEODYMIUM CHLORIDES
PRASEODYMIUM COMPOUNDS
PROMETHIUM CHLORIDES
PROMETHIUM COMPOUNDS
RARE EARTH COMPOUNDS
SAMARIUM CHLORIDES
SAMARIUM COMPOUNDS
SCATTERING
STABILITY
X-RAY DIFFRACTION