Lanthanum
121coordination compound — Chem. complex (def. 10). Also called coordination complex. * * * ▪ chemistry Introduction any of a class of substances with chemical structures in which a central metal atom is surrounded by nonmetal atoms or groups of atoms, called ligands… …
122misch metal — /mish/ a pyrophoric alloy, containing approximately 50 percent cerium and 45 percent lanthanum, made from a mixture of various rare earth chlorides by electrolysis. [1920 25; < G Mischmetall, equiv. to misch(en) to MIX + Metall METAL] * * * ▪… …
123monazite — /mon euh zuyt /, n. a reddish or yellowish brown mineral, a phosphate of cerium and lanthanum, (Ce,La)PO4: the principal ore of thorium. [1830 40; < G Monazit, equiv. to monaz ( < Gk monázein to be alone; see MON ) + it ITE1] * * * ▪ mineral… …
124superconductivity — superconduction /sooh peuhr keuhn duk sheuhn/, n. superconductive /sooh peuhr keuhn duk tiv/, superconducting, adj. superconductor /sooh peuhr keuhn duk teuhr/, n. /sooh peuhr kon deuhk tiv i tee/, n. Physics. the phenomenon of almost perfect… …
125ytterbium — ytterbic, ytterbous, adj. /i terr bee euhm/, n. Chem. a rare metallic element found in gadolinite and forming compounds resembling those of yttrium. Symbol: Yb; at. wt.: 173.04; at. no.: 70; sp. gr.: 6.96. Cf. rare earth element. [1875 80; < NL;… …
126actinide element — ▪ chemical element group Introduction any of a series of 15 consecutive chemical elements in the periodic table from actinium to lawrencium (atomic numbers 89–103). As a group they are significant largely because of their radioactivity.… …
127lanthanide contraction — ▪ chemistry also called lanthanoid contraction in chemistry, the steady decrease in the size of the atoms and ions of the rare earth elements (rare earth element) with increasing atomic number from lanthanum (atomic number 57) through… …
128lanthanide — noun Any of the 14 rare earth elements from cerium (or from lanthanum) to lutetium in the periodic table; because their outermost orbitals are empty, they have very similar chemistry; below them are the actinides. Syn: lanthanate …
