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Encyclopedia > Lanthanum
57 bariumlanthanumcerium
-

La

Ac
General
Name, Symbol, Number lanthanum, La, 57
Chemical series lanthanides
Group, Period, Block 3, 6, f
Appearance silvery white
Atomic mass 138.90547(7) g·mol−1
Electron configuration [Xe] 5d1 6s2
Electrons per shell 2, 8, 18, 18, 9, 2
Physical properties
Phase solid
Density (near r.t.) 6.162 g·cm−3
Liquid density at m.p. 5.94 g·cm−3
Melting point 1193 K
(920 °C, 1688 °F)
Boiling point 3737 K
(3464 °C, 6267 °F)
Heat of fusion 6.20 kJ·mol−1
Heat of vaporization 402.1 kJ·mol−1
Heat capacity (25 °C) 27.11 J·mol−1·K−1
Vapor pressure (extrapolated)
P(Pa) 1 10 100 1 k 10 k 100 k
at T(K) 2005 2208 2458 2772 3178 3726
Atomic properties
Crystal structure hexagonal
Oxidation states 3
(strongly basic oxide)
Electronegativity 1.10 (Pauling scale)
Ionization energies
(more)
1st: 538.1 kJ·mol−1
2nd: 1067 kJ·mol−1
3rd: 1850.3 kJ·mol−1
Atomic radius 195 pm
Covalent radius 169 pm
Miscellaneous
Magnetic ordering  ?
Electrical resistivity (r.t.) (α, poly) 615 nΩ·m
Thermal conductivity (300 K) 13.4 W·m−1·K−1
Thermal expansion (r.t.) (α, poly)
12.1 µm/(m·K)
Speed of sound (thin rod) (20 °C) 2475 m/s
Young's modulus (α form) 36.6 GPa
Shear modulus (α form) 14.3 GPa
Bulk modulus (α form) 27.9 GPa
Poisson ratio (α form) 0.280
Mohs hardness 2.5
Vickers hardness 491 MPa
Brinell hardness 363 MPa
CAS registry number 7439-91-0
Selected isotopes
Main article: Isotopes of lanthanum
iso NA half-life DM DE (MeV) DP
137La syn 60,000 yrs ε 0.600 137Ba
138La 0.09% 105×109yrs ε 1.737 138Ba
β- 1.044 138Ce
139La 99.91% La is stable with 82 neutrons
References

Lanthanum (IPA: /ˈlanθənəm/) is a chemical element in the periodic table that has the symbol La and atomic number 57. General Name, Symbol, Number barium, Ba, 56 Chemical series alkaline earth metals Group, Period, Block 2, 6, s Appearance silvery white Atomic mass 137. ... General Name, Symbol, Number cerium, Ce, 58 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 140. ... General Name, Symbol, Number actinium, Ac, 89 Chemical series actinides Group, Period, Block 3, 7, f Appearance silvery Atomic mass (227) g·mol−1 Electron configuration [Rn] 6d1 7s2 Electrons per shell 2, 8, 18, 32, 18, 9, 2 Physical properties Phase solid Density (near r. ... File links The following pages link to this file: Lanthanum User:Femto/elements e8 Categories: GFDL images ... This is a standard display of the periodic table of elements. ... This extended periodic table was suggested by Glenn T. Seaborg in 1969. ... This is a list of chemical elements, sorted by name and color coded according to type of element. ... Categories: Chemical elements ... sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex... The lanthanide series comprises the 15 elements from lanthanum to lutetium on the periodic table, with atomic numbers 57 through 71. ... A periodic table group is a vertical column in the periodic table of the chemical elements. ... In the periodic table of the elements, a period is a row of the table. ... A block of the periodic table of elements is a set of adjacent groups. ... A Group 3 element is an element in periodic table group 3 (IUPAC style) in the periodic table, which consists of: scandium (21) yttrium (39) lanthanum (57) - lutetium (71) actinium (89) - lawrencium (103) All of these elements are classed in Group 3 because their outer shell holds three electrons. ... A period 6 element is one of the chemical elements in the sixth row (or period) of the periodic table of the elements, including the Lanthanides. ... The f-block of the periodic table of elements consists of those elements for which, in the atomic ground state, the highest-energy electrons occupy f-orbitals. ... Color is an important part of the visual arts. ... Lanthanum sample. ... The atomic mass of a chemical element is the mass of an atom at rest, most often expressed in unified atomic mass units. ... To help compare different orders of magnitude we list here masses between 60. ... Hydrogen = 1 List of Elements in Atomic Number Order. ... Electron atomic and molecular orbitals In atomic physics and quantum chemistry, the electron configuration is the arrangement of electrons in an atom, molecule, or other physical structure (eg, a crystal). ... General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Atomic mass 131. ... e- redirects here. ... Example of a sodium electron shell model An electron shell, also known as a main energy level, is a group of atomic orbitals with the same value of the principal quantum number n. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... In jewelry, a solid gold piece is the alternative to gold-filled or gold-plated jewelry. ... In physics, Density is defined as mass m per unit volume V. Mathematically, it is expressed as where, in SI units: ρ (rho) is the density of the substance, measured in kg m-3 m is the mass of the substance, measured in kg v is the volume of the substance... Room temperature describes a certain temperature within enclosed space that is uses for various purposes by human beings. ... In physics, Density is defined as mass m per unit volume V. Mathematically, it is expressed as where, in SI units: ρ (rho) is the density of the substance, measured in kg m-3 m is the mass of the substance, measured in kg v is the volume of the substance... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... The Kelvin scale is a thermodynamic (absolute) temperature scale where absolute zero—the lowest possible temperature where nothing could be colder and no heat energy remains in a substance—is defined as zero kelvin (0 K). ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... Fahrenheit is a temperature scale named after the German physicist Daniel Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ... The boiling point of a substance is the temperature at which it can change its state from a liquid to a gas throughout the bulk of the liquid at a given pressure. ... The Kelvin scale is a thermodynamic (absolute) temperature scale where absolute zero—the lowest possible temperature where nothing could be colder and no heat energy remains in a substance—is defined as zero kelvin (0 K). ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... Fahrenheit is a temperature scale named after the German physicist Daniel Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ... Standard enthalpy change of fusion of period three. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... The standard enthalpy change of vaporization, ΔvHo, also (less correctly) known as the heat of vaporization is the energy required to transform a given quantity of a substance into a gas. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... In chemistry and physics, Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. ... Enargite crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... In chemical nomenclature, the oxidation number (formerly known as the Stock number) of an element in a molecule or complex is the charge that it would bear if all the ligands were removed along with the electron pairs that were shared with the central atom. ... A base in chemistry is a chemical substance which has a free pair of electrons to bind a hydrogen ion commonly referred to as a proton (IUPAC definition). ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... The ionization energy (IE) of an atom or of a molecule is the energy required to strip it of an electron. ... These tables list the ionization energy in kJ/mol necessary to remove an electron from a neutral atom (first energy), respectively from a singly, doubly, etc. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... The atomic radius is the distance from the atomic nucleus to the outermost stable electron orbital in an atom that is at equilibrium. ... You have big harry skanky balls ... Picometre (American spelling: picometer) is an SI measure of length that is equal to 10−12 of a metre. ... Covalent radius in chemistry corresponds to half of the distance between two identical atomic nuclei, bound by a covalent bond. ... You have big harry skanky balls ... Magnetic lines of force of a bar magnet shown by iron filings on paper In physics, magnetism is one of the phenomena by which materials exert an attractive or repulsive force on other materials. ... // Headline text POOP!! Danny Hornsby (also known as Gnome) is a measure indicating how strongly a Gnome can opposes the flow of electric current. ... Room temperature describes a certain temperature within enclosed space that is uses for various purposes by human beings. ... In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... During heat transfer, the energy that is stored in the intermolecular bonds between atoms changes. ... Room temperature describes a certain temperature within enclosed space that is uses for various purposes by human beings. ... The speed of sound is a term used to describe the speed of sound waves passing through an elastic medium. ... Metre per second (U.S. spelling: meter per second) is an SI derived unit of both speed (scalar) and velocity (vector), defined by distance in metres divided by time in seconds. ... This article is about a physical property. ... In materials science, shear modulus S, sometimes referred to as the modulus of rigidity, is defined as the ratio of shear stress to the shear strain: S = shear stress/shear strain = (F/A)/Φ. Another commonly accepted symbol is G. Shear modulus is usually measured in ksi (kips per square... The bulk modulus K of a fluid or solid is the inverse of the compressibility: where p is pressure and V is volume. ... Figure 1: Rectangular specimen subject to compression, with Poissons ratio circa 0. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. ... A Vickers hardness tester The Vickers hardness test was developed in the early 1920s as an alternative method to measure the hardness of materials. ... The Brinell scale characterises the indentation hardness of materials through the scale of penetration of an indenter, loaded on a material test-piece. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... Lanthanum (La) Standard atomic mass: 138. ... Isotopes are any of the several different forms of an element each having different atomic mass. ... Natural abundance refers to the prevalence of different isotopes of an element as found in nature. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... In physics, the decay mode describes a particular way a particle decays. ... The decay energy is the energy released by a nuclear decay. ... An electronvolt (symbol: eV) is the amount of energy gained by a single unbound electron when it falls through an electrostatic potential difference of one volt. ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... (Redirected from 1 E s) An order of magnitude is the class of scale or magnitude of any amount, where each class contains values of a fixed ratio to the class preceding it. ... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron... General Name, Symbol, Number barium, Ba, 56 Chemical series alkaline earth metals Group, Period, Block 2, 6, s Appearance silvery white Atomic mass 137. ... (Redirected from 1 E s) An order of magnitude is the class of scale or magnitude of any amount, where each class contains values of a fixed ratio to the class preceding it. ... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron... General Name, Symbol, Number barium, Ba, 56 Chemical series alkaline earth metals Group, Period, Block 2, 6, s Appearance silvery white Atomic mass 137. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... General Name, Symbol, Number cerium, Ce, 58 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 140. ... This article needs to be cleaned up to conform to a higher standard of quality. ... ≈≈ This article or section does not cite its references or sources. ... Recommended values for many properties of the elements, together with various references, are collected on these data pages. ... For information on how to read IPA transcriptions of English words see here. ... The periodic table of the chemical elements (this version outdated on October 13, 2006) A chemical element, or element for short, is a pure substance that cannot be decomposed into any simpler substance. ... The periodic table of the chemical elements is a tabular method of displaying the chemical elements, first devised in 1869 by the Russian chemist Dmitri Mendeleev. ... It has been suggested that List of elements by atomic number be merged into this article or section. ...

Contents

Notable characteristics

Lanthanum.
Lanthanum.

Lanthanum is a silvery white metallic element belonging to group 3 of the periodic table and often considered to be one of the lanthanides. Found in some rare-earth minerals, usually in combination with cerium and other rare earth elements. Lanthanum is malleable, ductile, and soft enough to be cut with a knife. It is one of the most reactive of the rare-earth metals. The metal reacts directly with elemental carbon, nitrogen, boron, selenium, silicon, phosphorus, sulfur, and with halogens. It oxidizes rapidly when exposed to air. Cold water attacks lanthanum slowly, while hot water attacks it much more rapidly. Image File history File links Lanthanum. ... Image File history File links Lanthanum. ... The lanthanide series is the 14 rare earth chemical elements which lie between lanthanum and ytterbium on the periodic table. ... General Name, Symbol, Number cerium, Ce, 58 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 140. ... Rare earth ore Rare earth elements and rare earth metals are trivial names sometimes applied to a collection of 17 chemical elements in the periodic table, namely scandium, yttrium, and the lanthanides. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Atomic mass 14. ... General Name, Symbol, Number boron, B, 5 Chemical series metalloids Group, Period, Block 13, 2, p Appearance black/brown Atomic mass 10. ... Se redirects here. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance as coarse powder, dark gray with bluish tinge Atomic mass 28. ... General Name, Symbol, Number phosphorus, P, 15 Chemical series nonmetals Group, Period, Block 15, 3, p Appearance waxy white/ red/ black/ colorless Atomic mass 30. ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Atomic mass 32. ... The halogens are a chemical series of nonmetals. ...


Applications

Uses of lanthanum:

Lighting refers to either artificial light sources such as lamps or to natural illumination of interiors from daylight. ... Film is a term that encompasses individual motion pictures, the field of film as an art form, and the motion picture industry. ... Lanthanum(III) oxide is a white solid. ... Glass can be made transparent and flat, or into other shapes and colors as shown in this sphere from the Verrerie of Brehat in Brittany. ... Image of two girls in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ... A camera is a device used to capture images, as still photographs or as sequences of moving images (movies or videos). ... A telescope (from the Greek tele = far and skopein = to look or see; teleskopos = far-seeing) is an instrument designed for the observation of remote objects. ... A lens. ... The refractive index (or index of refraction) of a material is the factor by which the phase velocity of electromagnetic radiation is slowed in that material, relative to its velocity in a vacuum. ... The old steel cable of a colliery winding tower Steel is an alloy whose major component is iron, with carbon content between 0. ... Malleability is a physical property of metals and metal alloys, or generally of any kind of matter. ... Ductility is the physical property of being capable of sustaining large plastic deformations without fracture (in metals, such as being drawn into a wire). ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... Pig iron is raw iron, the immediate product of smelting iron ore with coke and limestone in a blast furnace. ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Atomic mass 95. ... Mischmetal (from German: Mischmetall - mixed metals) is an unintentional alloy of rare earth elements in various naturally-occurring proportions. ... A pyrophoric substance is a substance that ignites spontaneously, that is, its autoignition temperature is below room temperature. ... Lanthanum(III) oxide is a white solid. ... Lanthanum hexaboride (LaB6, also called lanthanum boride and (incorrectly) LaB) is an inorganic chemical, a boride of lanthanum. ... In electronics, a vacuum tube or (outside North America) thermionic valve or just valve, is a device generally used to amplify, switch or otherwise modify, a signal by controlling the movement of electrons in an evacuated space. ... Hot cathode is also a name for a hot filament ionization gauge, a vacuum measuring device. ... e- redirects here. ... SEM Cambridge S150 at Geological Institute, University Kiel, 1980 SEM opened sample chamber The scanning electron microscope (SEM) is a type of electron microscope capable of producing high resolution images of a sample surface. ... Gas tungsten arc welding Gas tungsten arc welding (GTAW), commonly known as tungsten inert gas (TIG) welding, is an arc welding process that uses a nonconsumable tungsten electrode to produce the weld. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... General Name, Symbol, Number thorium, Th, 90 Chemical series Actinides Group, Period, Block n/a, 7, f Appearance silvery white Atomic mass 232. ... In petroleum geology and chemistry, cracking is the process whereby complex organic molecules (e. ... It has been suggested that this article or section be merged into Catalysis. ... For other uses of mantle see: mantle (disambiguation) An incandescent gas mantle, gas mantle, or Welsbach mantle is a device for generating bright white light when heated by a flame. ... Radiometric dating is a technique used to date materials based on a knowledge of the decay rates of naturally occurring isotopes, and the current abundances. ... In medicine, lanthanum carbonate is medication known as a phosphate binder. ... Phosphate binders are a group of medications used to reduce the absorption of phosphate and taken with meals and snacks. ... Hyperphosphatemia is an electrolyte disturbance in which there is an abnormally elevated level of phosphate in the blood. ... General Name, Symbol, Number cerium, Ce, 58 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 140. ... Lanthanum bromide (LaBr3) is a bromide of lanthanum, an inorganic compound. ... A scintillator is a device or substance that absorbs high energy (ionizing) electromagnetic or charged particle radiation then, in response, fluoresces photons at a characteristic Stokes-shifted (longer) wavelength, releasing the previously absorbed energy. ... Binomial name Armoracia rusticana P.G. Gaertn. ... Molecular biology is the study of biology at a molecular level. ...

History

Lanthanum was discovered in 1839 by Swedish chemist Carl Gustav Mosander, when he partially decomposed a sample of cerium nitrate by heating and treating the resulting salt with dilute nitric acid. From the resulting solution, he isolated a new rare earth he called lantana. Lanthanum was isolated in relatively pure form in 1923. 1839 (MDCCCXXXIX) was a common year starting on Tuesday (see link for calendar). ... Carl Gustaf Mosander (Kalmar 10 September 1797 – Lovö, Stockholm County 15 October Swedish chemist. ... The chemical compound nitric acid (HNO3), also known as aqua fortis and spirit of nitre, is an aqueous solution of hydrogen nitrate (anhydrous nitric acid). ... 1923 (MCMXXIII) was a common year starting on Monday (link will display the full calendar). ...


The word lanthanum comes from the Greek λανθανω [lanthanō] = to lie hidden.


Lanthanum is the most strongly basic of all the trivalent lanthanides, and this property is what allowed Mosander to isolate and purify the salts of this element. Basicity separation as operated commercially involved the fractional precipitation of the weaker bases (such as "didymium") by the addition of magnesium oxide or dilute ammmonia gas. Purified lanthanum remained in solution. (The basicity methods were only suitable for lanthanum purification; "didymium" could not be efficiently further separated in this manner.) The alternative technique of fractional crystallization was invented by Dimitry Mendeleev himself, in the form of the double ammonium nitrate tetrahydrate, which he used to separate the less-soluble lanthanum from the more-soluble "didymium" in the 1870's. This system would be used commercially in lanthanum purification until the development of practical solvent extraction methods that started in the late 1950's. (A detailed process using the double ammonium nitrates to provide 4N pure lanthanum, neodymium concentrates and praseodymium concentrates is presented in Callow 1967, at a time when the process was just becoming obsolete.) As operated for lanthanum purification, the double ammonium nitrates were recrystallized from water. When later adapted by Carl Auer won Welsbach for the splitting of "didymium", nitric acid was used as solvent to lower the solubiity of the system. Lanthanum is relatively easy to purify, since it has only one adjacent lanthanide, cerium, which itself is very readily removed due to its potential tetravalency.


Biological Role

Lanthanum has no known biological role. The element is not absorbed orally, and when injected its elimination is very slow. Lanthanum carbonate was approved as a medication (Fosrenol®, Shire Pharmaceuticals) to absorb excess phosphate in cases of end-stage renal failure. Some rare-earth chlorides, such as lanthanum chloride (LaCl3), are known to have anticoagulant properties. In medicine, lanthanum carbonate is medication known as a phosphate binder. ... Shire Pharmaceuticals is British manufacturer of pharmaceuticals products including Adderall and Carbatrol. ... Above is a ball-and-stick model of the inorganic hydrogenphosphate anion (HPO42−). Colour coding: P (orange); O (red); H (white). ... An anticoagulant is a substance that prevents coagulation; that is, it stops blood from clotting. ...


While Lanthanum has pharmacological effects on several receptors and ion channels its specificity for the GABA receptor is unique among divalent cations. Lanthanum acts at the same modulatory site on the GABAR as zinc- a known negative allosteric modulator. The Lanthanum cation La3+ is a positive allosteric modulator at native and recombinant GABA receptors, increasing open channel time and decreasing desensitization in a subunit configuration dependent manner.


Occurrence

Although lanthanum belongs to chemical elements group called rare earth metals, it is not rare at all. Lanthanum is available in relatively large quantities (32 ppm in Earth’s crust). "Rare earths" got their name since they were indeed rare as compared to the "common" earths such as lime or magnesia, and in the beginning, only a few deposits were known. Rare earth ore stupid Rare earth elements and rare earth metals are a collection of sixteen chemical elements in the periodic table, namely scandium, yttrium, and fourteen of the fifteen lanthanides (excluding promethium), which naturally occur on the Earth. ...


Monazite (Ce, La, Th, Nd, Y)PO4, and bastnasite (Ce, La, Y)CO3F, are the principal ores in which lanthanum occurs, in percentages of up to 25 to 38 percent of the total lanthanide content. Lanthanum is more generally enriched in bastnasite as opposed to monazite, in commercial orebodies. Until 1949, bastnasite was a rare and obscure mineral, not even remotely contemplated as a potential commercial source for lanthanides. In that year, the vast deposit at Mountain Pass California was discovered. This discovery alerted geologists as to the existence of a whole new class of rare earth deposit, the rare-earth bearing carbonatite, other examples of which soon surfaced, particularly in Africa and China. Monazite powder In geology, the mineral monazite is a reddish-brown phosphate containing rare earth metals and an important source of thorium, lanthanum, and cerium. ... In geology, the mineral bastnasite is one of a family of three carbonate-fluoride minerals. ...


See also category:Lanthanide minerals


Isotopes

Naturally occurring lanthanum is composed of one stable (139La) and one radioactive (138La) isotope, with the stable isotope, 139La, being the most abundant (99.91% natural abundance). 38 radioisotopes have been characterized with the most stable being 138La with a half-life of 105×109 years, and 137La with a half-life of 60,000 years. All of the remaining radioactive isotopes have half-lives that are less than 24 hours and the majority of these have half lives that are less than 1 minute. This element also has 3 meta states. Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... Isotopes are any of the several different forms of an element each having different atomic mass. ... Natural abundance refers to the prevalence of different isotopes of an element as found in nature. ... A radionuclide is an atom with an unstable nucleus. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... A nuclear isomer is a metastable state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ...


The isotopes of lanthanum range in atomic weight from 117 u (117La) to 155 u (155La). ... The unified atomic mass unit (u), or Dalton (Da), is a small unit of mass used to express atomic and molecular masses. ...


Precautions

Lanthanum has a low to moderate level of toxicity, and should be handled with care. In animals, the injection of lanthanum solutions produces glycaemia, low blood pressure, degeneration of the spleen and hepatic alterations. Glycemia is the concentration of glucose in the blood. ... The spleen is an organ of the upper abdomen, where it functions in the destruction of old red blood cells and holding a reservoir of blood. ... The liver is an organ in some animals, including vertebrates (and therefore humans). ...


References

  1. ^ Chau YP, Lu KS (1995). "Investigation of the blood-ganglion barrier properties in rat sympathetic ganglia by using lanthanum ion and horseradish peroxidase as tracers". ACTA ANATOMICA (BASEL) 153 (2): 135-144. PMID 8560966. 
  • Los Alamos National Laboratory – Lanthanum
  • "The Industrial Chemistry of the Lanthanons, Yttrium, Thorium and Uranium", by R.J. Callow, Pergamon Press 1967
  • "Chemistry of the Lanthanons", by R.C. Vickery, Butterworths 1953
  • "Nouveau Traite de Chimie Minerale, Vol. VII. Scandium, Yttrium, Elements des Terres Rares, Actinium", P. Pascal, Editor, Masson & Cie 1959
  • "Extractive Metallurgy of Rare Earths", by C.K. Gupta and N. Krishnamurthy, CRC Press 2005

External links

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Chemistry : Periodic Table : lanthanum : key information (409 words)
This sample is from The Elements Collection, an attractive and safely packaged collection of the 92 naturally occurring elements that is available for sale.
Lanthanum is silvery white, malleable, ductile, and soft enough to be cut with a knife.
Lanthanum metal is available commercially so it is not normally necessary to make it in the laboratory, which is just as well as it is difficult to separate it from as the pure metal.
Lanthanum - Products - HEFA Rare Earth Canada Ltd. (398 words)
Lanthanum Oxide is a kind of white powder used as the raw material of optical glass, optical fiber, catalyst and lanthanum metal.
Lanthanum Carbonate is a kind of white powder.
Lanthanum Nitrate is a kind of colorless granular crystal, used as raw material of catalyst and lanthanum compounds.
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