Rare earths Cerium group

The separation of light rare earths (cerium group) sulfates obtained from bastnasite by primary amine with or without an aqueous phase chelating reagent was studied by Bauer et al. (1968). Kerosene was used as the diluent. The pH of the lanthanide-amine system affects the molecular species present in both the aqueous and organic phases. The extraction of rare earths at high acid concentrations is inhibited due to the formation of stable amine bisulfate... 

A large deposit of loparite occurs ia the Kola Peninsula, Russia. The production of REO reaches 6500 t/yr. Loparite contains over 30% of rare-earth oxides from the cerium group. In addition, loparite contains up to 40% titanium oxide and up to 12% niobium and tantalum oxides. 

Group 3 (IIIB) and Inner Transition-Metal Perchlorates. The rare-earth metal perchlorates of yttrium and lanthanum have been reported (53). Tetravalent cerium perchlorate [14338-93-3] 06(0.04)4, and uranium perchlorate have also been identified (54). 

Rare earth. One of a group of 15 chemically related elements lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. 

Symbol Nd atomic number 60 atomic weight 144.24 a rare earth lanthanide element a hght rare earth metal of cerium group an inner transition metal characterized by partially filled 4/ subshell electron configuration [Xe]4/35di6s2 most common valence state -i-3 other oxidation state +2 standard electrode potential, Nd + -i- 3e -2.323 V atomic radius 1.821 A (for CN 12) ionic radius, Nd + 0.995A atomic volume 20.60 cc/mol ionization potential 6.31 eV seven stable isotopes Nd-142 (27.13%), Nd-143 (12.20%), Nd-144 (23.87%), Nd-145 (8.29%), Nd-146 (17.18%), Nd-148 (5.72%), Nd-150 (5.60%) twenty-three radioisotopes are known in the mass range 127-141, 147, 149, 151-156. 

Neodymium occurs in nature in the minerals hastnasite, monazite, cerite and allanite. The element always is associated with other rare earths, especially cerium group elements. Its abundance in the earth s crust is about 0.0024%. 

Cerium group of rare earths. A classic of science, Sci. News Letter, 20,... 

Double sulphate precipitation is one of the most common methods used in industry for the separation of cerium group from yttrium group rare earths. Various other precipitants such as chromates, double chromates, ferrocyanides, phosphates etc. have been tried. 

Formates. — The simplest Tnowo-carboxylic acid is formic acid (HCOOH). Formate complexes have not been extensively investigated although Sakkar [353] has mentioned rare earth formates. The cerium group rare earths form spherulic formates which are hexagonal. This property is used to identify small amounts of these elements. These formates are prepared by dissolving freshly prepared rare earth hydroxides in formic acid. 

LANTHANIDE SERIES. The chemical elements with atomic numbers 58 to 71 inclusive, commencing with cerium t.5K)and through lutetiuni 171) frequently ate termed collectively, the Lanthanide Scries. Lanthanum, the anchor element of the series, appears in group 3h of the periodic table. Some authorities eonsider lanthanum a part of the series. Members ol the series, along with lanthanum and yttrium, are described under Rare-Earth Elements and Metals. See also Actinide Series. 

Cement, laboratory, 1 189 Cerite, extraction of, 2 44 Cerium, phosphor containing strontium sulfide and, 3 23 separation of, from rare earth mixtures, 2 43, 47, 48 test for, 2 50 Cerium amalgam, 1 15 Cerium-group earths, separation of, from yttrium earths by doublesulfate method, 2 44, 46 Cerium (III) magnesium nitrate, 2Ce(N03)s-3Mg(N03)2-24H,0, separation of praseodymium from lanthanum by, 2 57 Cerium(III) nitrate, 2 51 Cerium (IV) nitrate, basic, 2 49 Cesium, cesium azide for preparation of, 1 79... 

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