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57 barium ← lanthanum → cerium
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↑
La
↓
Ac
General
Name, Symbol, Number lanthanum, La, 57
Chemical series lanthanides
Group, Period, Block 3, 6, f
Appearance silvery white
Standard atomic weight 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. Barium (ˈbɛəriəm is a Chemical element. It has the symbol Ba, and Atomic number 56 Cerium (ˈsɪəriəm is a Chemical element with the symbol Ce and Atomic number 58 Actinium (ækˈtɪniəm is a radioactive Chemical element with the symbol Ac and Atomic number 89 which was discovered in 1899, the earliest This is a typical display of the periodic table of the elements and contains the symbol and Atomic number of each element Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of Chemical elements, sorted by name Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of chemical elements by symbol, including the A table of Chemical elements ordered by Atomic number and color coded according to type of element In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in Terminology The Trivial name " Rare earths " is sometimes used to describe all the lanthanoids together with Scandium and Yttrium In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in In the Periodic table of the elements, a period is a horizontal row of the table A block of the Periodic table of elements is a set of adjacent groups The respective highest-energy electrons in each element in a block belong to the same Atomic Occurrence Scandium yttrium and the Lanthanides (except promethium tend to occur together in the Earth's crust and are relatively abundant compared with most D-block 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 the elements consists of those elements (sometimes referred to as the inner transition elements) for which in the The atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass To help compare different orders of magnitude, the following list describes various Mass levels between 10&minus36&thinsp kg and 1053&thinspkg In Atomic physics and Quantum chemistry, electron configuration is the arrangement of Electrons in an Atom, Molecule, or other Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J An electron shell may be crudely thought of as an Orbit followed by Electrons around an Atom nucleus. 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 A solid' object is in the States of matter characterized by resistance to Deformation and changes of Volume. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed 162  g·cm−3
Liquid density at m.p. 5. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different The melting point of a solid is the temperature range at which it changes state from solid to Liquid. 94  g·cm−3
Melting point 1193 K
(920 °C, 1688 °F)
Boiling point 3737 K
(3464 °C, 6267 °F)
Heat of fusion 6. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 The standard Enthalpy of fusion (symbol \Delta{}H_{fus} also known as the heat of fusion or specific melting heat, is the amount of 20  kJ·mol−1
Heat of vaporization 402. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material The enthalpy of vaporization, (symbol \Delta{}_{v}H also known as the heat of vaporization or heat of evaporation, is the Energy required 1  kJ·mol−1
Specific heat capacity (25 °C) 27. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the Temperature of a unit quantity 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. Vapor pressure (also known as equilibrium vapor pressure or saturation vapor pressure) is the Pressure of a Vapor in equilibrium In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. In Chemistry, the oxidation state is an indicator of the degree of Oxidation of an Atom in a Chemical compound. In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons 10 (Pauling scale)
Ionization energies
(more)		 1st:  538. The ionization potential, ionization energy or EI of an Atom or Molecule is the Energy required to remove an Electron These tables list the Ionization energy in kJ/mol necessary to remove one mole of Electrons from one mole of neutral gaseous Atoms (first energy respectively 1  kJ·mol−1
2nd:  1067  kJ·mol−1
3rd:  1850. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material 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. Atomic radius, and more generally the size of an atom, is not a precisely defined Physical quantity, nor is it constant in all circumstances A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth The covalent radius, r cov is a measure of the size of Atom which forms part of a Covalent bond. In Physics, magnetism is one of the Phenomena by which Materials exert attractive or repulsive Forces on other Materials. Electrical resistivity (also known as specific electrical resistance) is a measure of how strongly a material opposes the flow of Electric current. Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed In Physics, thermal conductivity, k is the property of a material that indicates its ability to conduct Heat. 4  W·m−1·K−1
Thermal expansion (r.t.) (α, poly)
12. When the Temperature of a substance changes the energy that is stored in the Intermolecular bonds between atoms changes Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed 1 µm/(m·K)
Speed of sound (thin rod) (20 °C) 2475 m/s
Young's modulus (α form) 36. Sound is a vibration that travels through an elastic medium as a Wave. In Solid mechanics, Young's modulus (E is a measure of the Stiffness of an isotropic elastic material 6  GPa
Shear modulus (α form) 14. In Materials science, shear modulus or modulus of rigidity, denoted by G, or sometimes S or μ, is defined as the ratio of Shear 3  GPa
Bulk modulus (α form) 27. 9  GPa
Poisson ratio (α form) 0. Poisson's ratio ( ν) named after Simeon Poisson, is the ratio of the relative contraction strain, or transverse strain (normal to 280
Mohs hardness 2. The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material 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. The Vickers hardness test was developed in 1924 by Smith and Sandland as an alternative method to measure the Hardness of materials The Brinell scale characterizes 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 They are also referred to Naturally occurring Lanthanum ( La) is composed of one stable (139La and one Radioactive (138La Isotope, with the stable Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides In Chemistry, natural abundance (NA refers to the abundance Isotopes of a Chemical element as naturally found on a planet Half-Life (computer-game page here It's already listed in the disambiguation page Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. The decay energy is the Energy released by a Nuclear decay. The energy difference of the Reactants is often written as Q: where Q In Nuclear physics, a decay product, also known as a daughter product, daughter isotope or daughter nuclide, is a 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 Seconds Years See also Natural history Geologic Electron capture (sometimes called inverse beta decay) is a Decay mode for Isotopes that will occur when there are too many Protons in the 600 137Ba
138La 0. Barium (ˈbɛəriəm is a Chemical element. It has the symbol Ba, and Atomic number 56 09% 105×109yrs ε 1. Seconds Years See also Natural history Geologic Electron capture (sometimes called inverse beta decay) is a Decay mode for Isotopes that will occur when there are too many Protons in the 737 138Ba
β- 1. Barium (ˈbɛəriəm is a Chemical element. It has the symbol Ba, and Atomic number 56 In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted 044 138Ce
139La 99. Cerium (ˈsɪəriəm is a Chemical element with the symbol Ce and Atomic number 58 91% 139La is stable with 82 neutrons
References

Lanthanum (pronounced /ˈlænθənəm/) is a chemical element with the symbol La and atomic number 57. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. Recommended values for many properties of the elements together with various references are collected on these data pages A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. See also List of elements by atomic number In Chemistry and Physics, the atomic number (also known as the proton

Contents

Notable characteristics

Lanthanum.
Lanthanum.

Lanthanum is a silvery white metallic element that belongs to group 3 of the periodic table and is a lanthanide. Terminology The Trivial name " Rare earths " is sometimes used to describe all the lanthanoids together with Scandium and Yttrium Found in some rare-earth minerals, usually in combination with cerium and other rare earth elements. Cerium (ˈsɪəriəm is a Chemical element with the symbol Ce and Atomic number 58 Rare earth elements and rare earth metals are according to IUPAC, the collection of seventeen Chemical elements in the Periodic table, namely 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. Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Boron (ˈbɔərɒn is a Chemical element with Atomic number 5 and the chemical symbol B. Selenium (səˈliniəm is a Chemical element with the Atomic number 34 represented by the chemical symbol Se, an atomic mass of 78 Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions It oxidizes rapidly when exposed to air. Cold water attacks lanthanum slowly, while hot water attacks it much more rapidly.

Applications

Uses of lanthanum:

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. Year 1839 ( MDCCCXXXIX) was a Common year starting on Tuesday (link will display the full calendar of the Gregorian Calendar (or a Common A chemist is a Scientist trained in the Science of Chemistry. Carl Gustaf Mosander ( Kalmar 10 September 1797 &ndash Lovö, Stockholm County 15 October, 1858) was a Nitric acid ( H[[nitrate NO3]] also known as Aqua fortis and spirit of nitre, is a highly corrosive and From the resulting solution, he isolated a new rare earth he called lantana. Lanthanum was isolated in relatively pure form in 1923. Year 1923 ( MCMXXIII) was a Common year starting on Monday (link will display the full calendar of the Gregorian 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) from nitrate solution by the addition of magnesium oxide or dilute ammonia gas. Didymium (twin element is a mixture of the elements Praseodymium and Neodymium. 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 1870s. This system would be used commercially in lanthanum purification until the development of practical solvent extraction methods that started in the late 1950s. (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 von Welsbach for the splitting of didymium, nitric acid was used as solvent to lower the solubility of the system. Carl Auer Freiherr von Welsbach ( 1 September 1858 - 4 August 1929) was an Austrian Scientist and Inventor who 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. Lanthanum carbonate, La 2( C[[Oxygen O]]33 is the Salt formed by Lanthanum (III Cations and Carbonate Shire plc ( ( ( TSX: SHPGY-Q is a British manufacturer of pharmaceuticals including Adderall XR, Carbatrol, Fosrenol A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. Some rare-earth chlorides, such as lanthanum chloride (LaCl3), are known to have anticoagulant properties. 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. Rare earth elements and rare earth metals are according to IUPAC, the collection of seventeen Chemical elements in the Periodic table, namely 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 historically only a few deposits were known.

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. In Geology, the Mineral monazite is a reddish-brown Phosphate -containing rare earth metals and an important source of Thorium The mineral bastnäsite is one of a family of three Carbonate - Fluoride minerals 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.

See also category:Lanthanide minerals

Isotopes

Main article: isotopes of lanthanum

Naturally occurring lanthanum is composed of one stable (139La) and one radioactive (138La) isotope, with the stable isotope, 139La, being the most abundant (99. Naturally occurring Lanthanum ( La) is composed of one stable (139La and one Radioactive (138La Isotope, with the stable Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides 91% natural abundance). In Chemistry, natural abundance (NA refers to the abundance Isotopes of a Chemical element as naturally found on a planet 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. A radionuclide is an Atom with an unstable nucleus, which is a nucleus characterized by excess energy which is available to be imparted either to a newly-created Half-Life (computer-game page here It's already listed in the disambiguation page Most 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. A nuclear isomer is a Metastable state of an Atomic nucleus caused by the excitation of one or more of its Nucleons A nuclear isomer occupies

The isotopes of lanthanum range in atomic weight from 117 u (117La) to 155 u (155La). The atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass The unified atomic mass unit ( u) or Dalton ( Da) or sometimes universal mass unit, is an unit of Mass used to express

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 or glycæmia is the concentration of Glucose in the Blood. The spleen is an organ found in all Vertebrate animals In humans the spleen is located in the abdomen of the body where it functions in the destruction of redundant Red The liver is a vital organ in the human body and is present in Vertebrates and some other animals

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.  

See also

Lanthanum compounds

External links

Dictionary

lanthanum

-noun

  1. A metallic chemical element (symbol La) with an atomic number of 57.
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