THE LANTHANUM—BORON SYSTEM

Journal Article · Thu Jun 01 04:00:00 EDT 1961 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100824a004· OSTI ID:4038694

Johnson, Robert W.; Daane, A. H.

From thermal, metallographic, x-ray, and electrical resistance data a phase diagram is proposed for the lanthanum-boron system. Two compounds are formed, LaB₆ and LaB₆. The former has a very narrow range of homogeneity and decomposes peritectically at 1800 plus or minus 15 deg . The crystal system is tetragonal, and the compound is a metallic type conducter. LaB₆ exists in the range 85.8 to 88% boron, melts above 2500 deg , and has a simple cubic lattice. The color of this compound changes with composition, going from purple to a bright blue with increasin boron content. The addition of boron to lanthanum has no measurable effect on the melting point or transition points of the metal. The addition of lanthanum to boron appears to have very little effect on the melting point of boron. There is metallographic evidence for an allotropic transformation in boron above 2100 deg . Evidence also is given for a new compound CaB₄, which appears to be isomorphous with LaB₄. (auth)

• Research Organization: Ames Lab., Ames, Iowa
• Sponsoring Organization: USDOE
• NSA Number: NSA-15-022798
• OSTI ID: 4038694
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 6 Vol. 65; ISSN 0022-3654
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALLOTROPY
BORON
CALCIUM BORIDES
COLOR
CRYSTALS
DECOMPOSITION
DIFFRACTION
DISTRIBUTION
ELECTRIC CONDUCTIVITY
LANTHANUM
LANTHANUM BORIDES
LATTICES
MELTING POINTS
METALLOGRAPHY
METALS, CERAMICS, AND OTHER MATERIALS
PHASE DIAGRAMS
TEMPERATURE
X RADIATION