lanthanum

[lan-thuh-nuhm]

noun

Chemistry.

1. a rare-earth, trivalent, metallic element, allied to aluminum, found in certain minerals, as monazite. La; 138.91; 57; 6.15 at 20°C.

lanthanum

/ ˈlænθənəm /

noun

1. a silvery-white ductile metallic element of the lanthanide series, occurring principally in bastnaesite and monazite: used in pyrophoric alloys, electronic devices, and in glass manufacture. Symbol: La; atomic no: 57; atomic wt: 138.9055; valency: 3; relative density: 6.145; melting pt: 918°C; boiling pt: 3464°C

lanthanum

1. A soft, malleable, silvery-white metallic element of the lanthanide series. It is used to make glass for lenses and lights for movie and television studios. Atomic number 57; atomic weight 138.91; melting point 920°C; boiling point 3,469°C; specific gravity 5.98 to 6.186; valence 3.

2. See Periodic Table

Word History and Origins

Origin of lanthanum¹

< New Latin (1841), equivalent to lanthan- (< Greek lanthánein to escape notice; referring to its position on the periodic table) + -um, variant of -ium -ium

Word History and Origins

Origin of lanthanum¹

C19: New Latin, from Greek lanthanein to lie unseen

Example Sentences

"The objective of the liquid separation unit will be to purify cerium on one side, lanthanum on the other side," explains production manager Florian Gouneau as we walk up a flight of metal stairs.

From BBC

Most rare earth elements are lanthanides, elements from 57 -- lanthanum -- to 71 -- lutetium -- on the periodic table.

From Science Daily

But, at room temperature, the number of hydrogens attached to lanthanum fluctuates between 2 and 3, making it impossible to have efficient conduction.

From Science Daily

Loeb says traces of three rare elements — beryllium, lanthanum and uranium — suggest the spheres come from outside of our solar system.

From Salon

However, five of the spherules were unusually enriched in beryllium and lanthanum, and, to a lesser degree, uranium.

From Science Magazine