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Showing papers on "Lanthanum published in 1976"


Book
01 Jan 1976
TL;DR: The Periodic Table and the Chemistry of the Elements as discussed by the authors are the main sources of information about the transition elements of the periodic table and their relationships with the transition metal complexes with TT-Acceptor (TT-Acid) ligands.
Abstract: FIRST PRINCIPLES Some Preliminaries The Electronic Structure of Atoms Structure and Bonding in Molecules Ionic Solids The Chemistry of Selected Anions Coordination Chemistry Solvents, Solutions, Acids and Bases The Periodic Table and the Chemistry of the Elements THE MAIN GROUP ELEMENTS Hydrogen The Group IA(1) Elements: Lithium, Sodium, Potassium, Rubidium and Cesium The Group IIA(2) Elements: Beryllium, Magnesium, Calcium, Strontium and Barium Boron The Group IIIB(13) Elements: Aluminum, Gallium, Indium and Thallium Carbon The Group IVB(14) Elements: Silicon, Germanium, Tin and Lead Nitrogen The Group VB(15) Elements: Phosphorus, Arsenic, Antimony and Bismuth Oxygen The Group VIB(16) Elements: Sulfur, Selenium, Tellurium and Polonium The Halogens: Fluorine, Chlorine, Bromide and Astatine The Noble Gases Zinc, Cadmium and Mercury THE TRANSITION ELEMENTS Introduction to Transition Elements: Ligand Field Theory The Elements of the First Transition Series The Elements of the Second and Third Transition Series Scandium, Yttrium, Lanthanum and the Lanthanides The Actinide Elements SOME SPECIAL TOPICS Metal Carbonyls and Other Transition Metal Complexes with TT-Acceptor (TT-Acid) Ligands Organometallic Compounds Stoichiometric and Catalytic Reactions of Organometallic Compounds Bio-Inorganic Chemistry Index.

2,102 citations


Journal ArticleDOI
TL;DR: In this paper, a study of the core-electron X-ray photoelectron (X-p) spectra of the f0 compounds La2O3, LaMO3(M = Fe and Co), CeO2, and BaCeO3 is described.
Abstract: A study of the core-electron X-ray photoelectron (X-p.e.) spectra of the f0 compounds La2O3, LaMO3(M = Fe and Co), CeO2, and BaCeO3 is described. Results on the chelate species [La(tmhd)3] and [Ce(tmhd)4](tmhd = 2,2,6,6-tetramethylheptane-3,5-dionato) are included for comparison. Special precautions have been taken to ensure an optimal degree of surface purity of the samples. Satellite structure has been observed for the 4p, in addition to the 3d and 4d, signals in both the lanthanum(III) and cerium(IV) compounds. These satellites arc discussed in terms of coexcitations of the charge-transfer type, principally O 2p→ metal 4f transitions. In the cerium(IV) oxides the satellites are apparently due to energy-gain (representing ‘ shake-down ’) rather than energy-loss (shake-up) processes.

841 citations




Journal ArticleDOI
TL;DR: In this paper, the standard free energies of formation of the oxides, sulfides and oxysulfides of cerium and lanthanum under steelmaking conditions have been calculated and used to predict the behavior of rare earths in steelmaking.
Abstract: The standard free energies of formation of the oxides, sulfides and oxysulfides of cerium and lanthanum under steelmaking conditions have been calculated and used to predict the behavior of rare earths in steelmaking. Deoxidation and desulfurization constants, expressed in terms of Henrian activities, have been used to construct a precipitation diagram which indicates the sequence of rare earth inclusion formation. An enrichment of lanthanum in (RE)-oxysulfide and cerium in (RE)-sulfide is predicted. It is also predicted that rare earths should be able to reduce the soluble oxygen and sulfur contents of liquid steel well below the contents presently found in most industrial and laboratory practices. A simple method of calculating steelmaking additions for complete rare earth control of inclusion composition is presented.

109 citations


Journal ArticleDOI
TL;DR: A single-crystal X-ray study of trinitrato-cis,syn,cis-2,5,8,15,18,21-hexacosanelanthanum shows the metal ion to be co-ordinated to six polyether oxygen atoms and three bidentate nitrate ions; structural parameters are discussed as discussed by the authors.
Abstract: A single-crystal X-ray study of trinitrato-cis,syn,cis-2,5,8,15,18,21-hexaoxatricyclo[20,4,0, 09,14]hexacosanelanthanum shows the metal ion to be co-ordinated to six polyether oxygen atoms and three bidentate nitrate ions; structural parameters are discussed.

49 citations


Journal ArticleDOI
TL;DR: In this paper, the stability of LaNi intermetallic compounds was studied and showed a gradual increase in the stability as Ni concentration increases from LaNi to LaNi/sub 5/ accompanied by a corresponding decrease in the matching ternary hydride.
Abstract: H absorption by La--Ni intermetallic compounds was studied. Results show a gradual increase in the stability of the intermetallic compound as the Ni concentration increases from LaNi to LaNi/sub 5/ accompanied by a corresponding decrease in the stability of the matching ternary hydride. (JRD)

47 citations



Patent
02 Dec 1976
TL;DR: In this paper, the authors define a permanent magnet alloy having the formula RE(Col-u-v-w-x-yFeuM Xy)z, where RE is samarium, cerium or cerium misch metal (MM), praseodymium, neodynium, lanthanum or mixtures thereof, X is Al, Cu or a mixture thereof.
Abstract: OF THE DISCLOSURE A permanent-magnet alloy having the formula RE(Col-u-v-w-x-yFeuM Xy)z wherein RE is samarium, cerium, cerium misch metal (MM), praseodymium, neodymium, lanthanum or mixtures thereof, X is Al, Cu or a mixture thereof, and 0.05 < u < 0.15 0.05 < y < 0.02 6.5 < z < 8.5 and M is at least one of Mnv, Crw and Vx wherein 0.003 ? v < 0.15 0.003 ? w < 0.10 0.003 ? x < 0.10.

40 citations


Journal ArticleDOI
01 May 1976-Talanta
TL;DR: In this article, a method was developed for accurate determination of small amounts of rare earths and yttrium in a variety of rocks, including syenites SY-1, SY-2 and SY-3, and some minerals such as britholite, cenosite, chevkinite, allanite, apatite and sphene.

35 citations


Journal ArticleDOI
TL;DR: It was shown that lanthanum may enter the cytoplasmic phase of undifferentiated cells in barley root tips by means of electron microscopy and X-ray energy spectroscopy and the nucleolus in particular proved to be a site with a high affinity for Lanthanum.
Abstract: By means of electron microscopy and X-ray energy spectroscopy (CORA in the transmission mode) it was shown that lanthanum may enter the cytoplasmic phase of undifferentiated cells in barley root tips. The nucleolus in particular proved to be a site with a high affinity for lanthanum. This finding is discussed in relation to the inhibition of root growth which has been reported to occur when root tips are exposed to polyvalent cations.

Journal ArticleDOI
TL;DR: In this paper, the lanthanum β-alumina phase doped with europium was investigated by X-ray diffraction and fluorescence, and it was shown that the structure of the mirror plane in which the ions are located is deeply modified.

Journal ArticleDOI
TL;DR: In this article, the authors studied the chemiluminescent emission which results when a thermal beam of La atoms intersects a tenuous atmosphere (10−6 to 10−4 torr) of one of the thermal oxidants O2, NO2, N2O, or O3 (300 K).
Abstract: Using a beam–gas arrangement, we have studied the chemiluminescent emission which results when a thermal beam of La atoms (1750–2400 K) intersects a tenuous atmosphere (10−6 to 10−4 torr) of one of the thermal oxidants O2, NO2, N2O, or O3 (300 K). The La–O2 reaction is characterized by visible chemiluminescence from the B 2Σ+ and C 2Π states of LaO. The La–NO2, La–N2O, and La–O3 reactions are characterized by emission from the B 2Σ+, C 2Π, and D 2Σ+ states of LaO. In addition all four systems are characterized by extensive emission from the A 2Π state of LaO. From the chemiluminescent spectrum for the La–O2 system, a minimum value of 8.19±0.04 eV is deduced for the dissociation energy of lanthanum monoxide. This lower bound is in good agreement with previous mass spectrometric determinations (8.28±0.11 and 8.38±0.2 eV). We discuss the temperature dependence of the four chemiluminescent reactions deducing an upper bound for the heat of vaporization of lanthanum metal. We combine the results of our temperat...



Patent
Thomas J. Gray1
19 Apr 1976
TL;DR: In this paper, an electrode is described which is comprised of an electroconductive substrate having an exterior surface of perovskite of the emperical formula A A' B 0.3 (I) a.
Abstract: An electrode is described which is comprised of an electroconductive substrate having an exterior surface of perovskite of the emperical formula A A' B 0.sub.3 (I) a. wherein A is lanthanum, B. wherein A' is an alkaline earth metal selected from the group consisting of calcium, strontium, barium, and mixtures thereof, C. wherein B is a transition metal selected from the group consisting of cobalt, chromium, tungsten, molybdenum, manganese, iron, nickel, rhenium, uranium, and mixtures thereof, D. wherein the atomic ratio of A:A' is in the range from about 0.05:1 to about 0.95:1, E. wherein the valence of A + A' + B = 6, f. wherein said electrode has a resistivity preferably less than about 10 milliohm-centimeters -1 , and G. wherein said perovskite is substantially insoluble in the electrolyte contacting said electrode under typical conditions of electrolysis.

Patent
13 Dec 1976
TL;DR: Alumina-based bodies having resistance to temperatures of up to 1200°C prepared by autoclaving alumina and at least one additive from the group of oxides of lanthanum, neodymium, prasehodmium and thorium are useful in adsorption and catalysis.
Abstract: Alumina based bodies having resistance to temperatures of up to 1200° C prepared by autoclaving alumina and at least one additive from the group of oxides of lanthanum, neodymium, praseodymium and thorium. Bodies of the alumina of this invention are useful in adsorption and catalysis.

Patent
02 Sep 1976
TL;DR: A nonlinear resistor comprises a sintered body of a ceramic composition which comprises 99.93 to 50 mole % of zinc oxide as ZnO; 0.01 to 10 mole percent of a specific rare earth oxide as R2 O3 (R represents lanthanum, praseodymium, neodynium, samarium, europium, gadolinium, terbium, dysprosium, holmium and erbium), thulium, ytterbium or lutetium) and 0.05 to 30
Abstract: A non-linear resistor comprises a sintered body of a ceramic composition which comprises 99.93 to 50 mole % of zinc oxide as ZnO; 0.01 to 10 mole % of a specific rare earth oxide as R2 O3 (R represents lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium) 0.01 to 10 mole % of an alkaline earth oxide as MO (M represents calcium, strontium or barium) and 0.05 to 30 mole % of cobalt oxide as CoO.

Patent
02 Sep 1976
TL;DR: In this article, a phosphor for infrared-to-visible conversion comprising a complex rare earth fluoride as a main ingredient and zinc fluoride having a general composition expressed by one of the following formulas is presented.
Abstract: A phosphor for infrared-to-visible conversion comprising a complex rare earth fluoride as a main ingredient and zinc fluoride having a general composition expressed by one of the following formulas: (Y.sub.1-x-y Yb.sub.x A.sub.y) F.sub.3.sup.. αZnF.sub.2 (la.sub.1-x-y Yb.sub.x A.sub.y) F.sub.3.sup.. αZnF.sub.2 and (Lu.sub.1-x-y Yb.sub.x A.sub.y) F.sub.3.sup.. αZnF.sub.2 wherein x is in the range of from 0.05 to 0.5, y is in the range of from 0.002 to 0.09 when yttrium fluoride is the host material and from 0.001 to 0.1 when lanthanum or lutetium fluoride is the host material, α is in the range of from 1.6 × 10 -4 to 1.6 × 10 -3 grams with respect to 1 gram of the phosphor and A is at least one member selected from Er and Ho.

Journal ArticleDOI
TL;DR: In this paper, the preparation of hydroxide chlorides of lanthanum, praseodymium, and neodynium has been achieved by hydrothermal methods at 550°C and 1530 atm.

Patent
21 May 1976
TL;DR: In this article, the authors proposed a method for electro materials based on lanthanum and nickel having a formula close to LaNi 5 in which one of the components is partially substituted by a metal selected from those in groups Ia, II, III, IV and Va of the periodic table of elements, and other than lanthanides.
Abstract: The invention relates to electro materials based on lanthanum and nickel having a formula close to LaNi 5 in which one of the components is partially substituted by a metal selected from those in groups Ia, II, III, IV and Va of the periodic table of elements, and other than lanthanides, in an atomic proportion which is not zero, being higher than 0.1% and lower than 25%, and preferbly from 0.5% to 15% with respect to the lanthanum.


Journal ArticleDOI
TL;DR: Lanthanum(III) perchlorate has been found to catalyse a novel reaction between cyclic secondary amines and acetonitrile giving 4-substituted-2,6-dimethylpyrimidines.
Abstract: Lanthanum(III) perchlorate has been found to catalyse a novel reaction between cyclic secondary amines and acetonitrile giving 4-substituted-2,6-dimethylpyrimidines.

Journal ArticleDOI
TL;DR: In this paper, the crystal structures of the lanthanum and samarium compounds have been determined and solved by conventional Patterson and Fourier, methods and refined to R 0.09 (La) and 0.08 (Sm).
Abstract: Triphenylphosphine oxide reacts with the anionic complexes [Ln{S2P(OEt)2}4]–(Ln = La–Lu, excluding Pm and Y) in ethanolic solution to displace one (La–Pr) or two (Nd–Lu and Y) ligands and form the neutral complexes [Ln{S2P(OEt)2}3(POPh3)2] or the cationic complexes [Ln{S2P(OEt)2}2(POPh3)2]+. The crystal structures of the lanthanum and samarium compounds have been determined.The lanthanum compound crystallises in space group P21/c with a= 19.66(2), b= 12.54(1), c= 24.11 (3)A, β= 94.16(8)°, and Z= 4, and the samarium compound in space group P21, with a= 17.90(2), b= 16.84(1)c= 12.54(2)A, β= 99.98(10)°, and Z= 2. Both structures were solved by conventional Patterson and Fourier, methods and refined to R 0.09 (La) and 0.08 (Sm).The neutral lanthanum complex has a square antiprismatic structure. The cationic samarium complex has a pentagonal bipyramidal structure. The nature of the bonding is discussed.


Journal ArticleDOI
TL;DR: In this paper, the formation constants of zinc ion binary complexes at various pH values were computed and the principles of metal-metal stimulation phenomena in viva were discussed, where both calcium and lanthanum ions encourage the formation of neutral membrane-permeable complexes of zinc ions.
Abstract: Potentiometric studies are reported for calcium(II), lanthanum(III), and zinc(II) binary complexes and for calcium(II) and zinc(II) or lanthanum(III) and zinc(II) ternary complexes of glutathionate at 37 °C and 0.15 10–3 mol dm–3(Na+)[ClO4]. Formation constants have been computed and used to calculate the concentrations of the complexes at various pH. Both calcium and lanthanum ions encourage the formation of neutral membrane-permeable complexes of zinc ions and the systems are used to discuss the principles of metal–metal stimulation phenomena in viva.

Journal ArticleDOI
TL;DR: In this paper, six sulfonazo-III isomers were synthesized and their color reactions with alkaline earth metals and lanthanum investigated, and the effects of water-miscible solvents were also described.

Journal ArticleDOI
M. Pezat1, Bernard Tanguy1, M. Vlasse1, Josik Portier1, Paul Hagenmuller1 
TL;DR: The reaction of rare-earth nitrides with fluorides or pyrolysis of these fluorides in gaseous ammonia atmosphere leads, in the case of lanthanum, cerium, and gadolinium, to nitride fluorides of general formula LnNxF3−3x as mentioned in this paper.

Journal ArticleDOI
15 Oct 1976-Science
TL;DR: Crushed and etched lanthanum lead manganite crystals containing as little as 0.005 atomic percent platinum have significantly higher catalytic activity than free platinum crystals due to an almost 100-fold segregation of platinum on the surface.
Abstract: Crushed and etched lanthanum lead manganite (La 0.7 Pb 0.3 MnO 3 ) crystals containing as little as 0.005 atomic percent platinum have significantly higher catalytic activity than free platinum crystals. This higher activity is due to an almost 100-fold segregation of platinum on the surface. The surface platinum concentration found, 0.5 atomic percent, is sufficient to account for the enhanced activity provided that the platinum has the same activity as platinum supported on alumina.

Journal ArticleDOI
TL;DR: In this article, the superoxide anion radical O−2 has been observed on lanthanum exchanged X and Y zeolites and adsorbed diamagnetic oxygen species on calcium and iron exchanged X zeolite.
Abstract: Under suitable conditions, the activation of cerium exchanged X and Y zeolites in oxygen or nitrous oxide gives rise to the formation of anion radicals O–2 and O– or dianions O2–2 and O2–, and presumably also O–3 on the zeolites. The superoxide anion radical O–2 has been observed on lanthanum exchanged X and Y zeolites and adsorbed diamagnetic oxygen species on calcium and iron exchanged Y zeolites. The behaviour of the individual adsorbed oxygen species was studied on these zeolites.