Lanthanum monochloride and lanthanum sesquichloride
Synthesis of LaCl from La and LaCl/sub 3/ in nearly quantitative yield is attained with powdered La (from LaH/sub x/) and 30-day equilibration periods at 745 to 820/sup 0/C provided either the LaCl/sub 3/ is first fused to provide intimate contact with the excess La or the reactants in stoichiometric proportions are pressed to approx. 1000 atm within the welded Ta container prior to reaction. Negligible yields are obtained with La sheet. Data from a single-crystal refinement of the LaCl structure (ZrBr type) are reported (R3m; a = 4.1026 (6) A, c = 27.597 (6) A; R = 0.086; 150 independent reflections with thetatheta < 55/sup 0/). LaCl decomposes peritectically at 825 to 826/sup 0/C, close to the eutectic temperature of the binary LaCl/sub 3/-La system. Needles of La/sub 2/Cl/sub 3/(Gd/sub 2/Cl/sub 3/ type) are also formed in incomplete reactions (a = 15.890 (9) A, b = 4.404 (2) A, c = 10.231 (9) A, ..beta.. = 119.14 (7)/sup 0/). The La-La distances in these phases are quite large in comparison with those known for analogous yttrium and terbium phases, and the Pauling bond orders per electron pair summed over all independent distances give a similar picture (LaCl 0.49 vs YCl 0.94). The large distances and reduced bonding in the expanded La-La arrays relative to the metal may arise from a loss of the significant 4f contribution which has been proposed for the pure metal.
- Research Organization:
- Ames Lab., IA
- DOE Contract Number:
- W-7405-ENG-82; WPAS-KC-02-03
- OSTI ID:
- 6255850
- Journal Information:
- Inorg. Chem.; (United States), Vol. 20:9
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
LANTHANUM
PHASE STUDIES
LANTHANUM CHLORIDES
CRYSTAL STRUCTURE
DECOMPOSITION
SYNTHESIS
BOND ANGLE
BOND LENGTHS
EXPERIMENTAL DATA
HIGH PRESSURE
LATTICE PARAMETERS
POWDERS
VERY HIGH TEMPERATURE
X-RAY DIFFRACTION
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
COHERENT SCATTERING
DATA
DIFFRACTION
DIMENSIONS
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
INFORMATION
LANTHANUM COMPOUNDS
LENGTH
METALS
NUMERICAL DATA
RARE EARTH COMPOUNDS
RARE EARTHS
SCATTERING
400201* - Chemical & Physicochemical Properties
400301 - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)