THE LANTHANUM-BORON SYSTEM

Journal Article · Thu Jun 01 04:00:00 EDT 1961 · Journal of Physical Chemistry (U.S.)

DOI:https://doi.org/10.1021/j100824a004· OSTI ID:4002904

Johnson, R 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, LaB/sub 4/ and LaB/sub 6/. 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 conductor. LaB/ sub 6/ exists in the range 85.8 to 88% boron, melts above 2500 deg , and has a simple cubic lattice. The coibr of the compound changes with composition, going from purple to a bright blue with increasing 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 CaB/sub 4/, which appears to be isomorphous with LaB/sub 4/. (auth)

• Research Organization: Ames Lab., Ames, Iowa
• Sponsoring Organization: USDOE
• NSA Number: NSA-15-026589
• OSTI ID: 4002904
• Report Number(s): IS-151; 0022-3654
• Journal Information: Journal of Physical Chemistry (U.S.), Journal Name: Journal of Physical Chemistry (U.S.) Vol. Vol: 65; ISSN JPCHA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

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