59 cerium ← praseodymium → neodymium - ↑ Pr ↓ Pa Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	praseodymium, Pr, 59
Chemical series	lanthanides
Group, Period, Block	n/a, 6, f
Appearance	grayish white
Standard atomic weight	140.90765(2) g·mol−1
Electron configuration	[Xe] 4f3 6s2
Electrons per shell	2, 8, 18, 21, 8, 2
Physical properties
Phase	solid
Density (near r.t.)	6.77 g·cm−3
Liquid density at m.p.	6.50 g·cm−3
Melting point	1208 K (935 °C, 1715 °F)
Boiling point	3793 K (3520 °C, 6368 °F)
Heat of fusion	6.89 kJ·mol−1
Heat of vaporization	331 kJ·mol−1
Heat capacity	(25 °C) 27.20 J·mol−1·K−1
Vapor pressure P(Pa) 1 10 100 1 k 10 k 100 k at T(K) 1771 1973 (2227) (2571) (3054) (3779)
Atomic properties
Crystal structure	hexagonal
Oxidation states	3 (mildly basic oxide)
Electronegativity	1.13 (Pauling scale)
Ionization energies (more)	1st: 527 kJ·mol−1
	2nd: 1020 kJ·mol−1
	3rd: 2086 kJ·mol−1
Atomic radius	185 pm
Atomic radius (calc.)	247 pm
Miscellaneous
Magnetic ordering	no data
Electrical resistivity	(r.t.) (α, poly) 0.700 µΩ·m
Thermal conductivity	(300 K) 12.5 W·m−1·K−1
Thermal expansion	(r.t.) (α, poly) 6.7 µm/(m·K)
Speed of sound (thin rod)	(20 °C) 2280 m/s
Young's modulus	(α form) 37.3 GPa
Shear modulus	(α form) 14.8 GPa
Bulk modulus	(α form) 28.8 GPa
Poisson ratio	(α form) 0.281
Vickers hardness	400 MPa
Brinell hardness	481 MPa
CAS registry number	7440-10-0
Selected isotopes
Main article: Isotopes of praseodymium iso NA half-life DM DE (MeV) DP 141Pr 100% Pr is stable with 82 neutrons 142Pr syn 19.12 h β- 2.162 142Nd ε 0.745 142Ce 143Pr syn 13.57 d β- 0.934 143Nd
References

Praseodymium (IPA: /ˌpreɪzioʊˈdɪmiəm/ or /ˌpreɪsioʊˈdɪmiəm/) is a chemical element in the periodic table that has the symbol Pr and atomic number 59. 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 neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Atomic mass 144. ... General Name, Symbol, Number protactinium, Pa, 91 Chemical series actinides Group, Period, Block ?, 7, f Appearance bright, silvery metallic luster Atomic mass 231. ... Image File history File links Praseodymium table image created by schnee, June 22, 2003 for Wikipedia. ... 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. ... A table of chemical elements ordered by atomic number and color coded according to type of element. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... The lanthanide series comprises the 15 elements from lanthanum to lutetium on the periodic table, with atomic numbers 57 through 71. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... 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. ... 6 *Lanthanides 7 **Actinides IUPAC has not recommended a specific format for the periodic table, so different conventions are permitted and are often used for the group number of lanthanides and actinides. ... 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. ... Praseodymium sample. ... The atomic mass (ma) 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. ... For other uses, see Solid (disambiguation). ... In physics, density is defined as mass m per unit volume V. For the common case of a homogeneous substance, 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... 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. For the common case of a homogeneous substance, 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... 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. ... Heat of fusion is the amount of heat energy which must be absorbed or lost for 1 gram of a substance to change states from a solid to a liquid or vice versa. ... The joule per mole (symbol: J·mol-1) is an SI derived unit of energy per amount of material. ... 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. ... The joule per mole (symbol: J·mol-1) is an SI derived unit of energy per amount of material. ... 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. ... The oxidation number of an element in a molecule or complex is the charge that it would have if all the ligands were removed along with the electron pairs that were shared with the central atom[1]. It is used in the inorganic nomenclature of inorganic compounds. ... Acids and bases: Acid-base reaction theories pH Self-ionization of water Buffer solutions Systematic naming Electrochemistry Acid-base extraction Acids: Strong acids Weak acids Mineral acids Organic acids Bases: Strong bases Weak bases Organic bases edit In chemistry, a base is most commonly thought of as a substance that... 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 ... One picometre is defined as 1x10-12 metres, in standard units. ... 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 does not adequately cite its references or sources. ... 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 substance essentially measures the substances resistance to uniform compression. ... Figure 1: Rectangular specimen subject to compression, with Poissons ratio circa 0. ... 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. ... Praseodymium (Pr) Standard atomic mass: 140. ... Isotopes are any of the several different forms of an element each having different atomic mass (mass number). ... 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. ... OK : Radioactive and Radioactivity redirect here. ... The decay energy is the energy released by a nuclear decay. ... The electronvolt (symbol eV, or, rarely and incorrectly, ev) is a unit of energy. ... 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. ... This article needs to be cleaned up to conform to a higher standard of quality. ... This article or section does not adequately cite its references or sources. ... 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. ... 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 neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Atomic mass 144. ... 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 cerium, Ce, 58 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 140. ... 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. ... Water, Rabbit, and Deer: three of the 20 day symbols in the Aztec calendar, from the Aztec Sun Stone. ... 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 neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Atomic mass 144. ... Recommended values for many properties of the elements, together with various references, are collected on these data pages. ... Not to be confused with the NATO phonetic alphabet, which has also informally been called the “International Phonetic Alphabet”. For information on how to read IPA transcriptions of English words, see IPA chart for English. ... The periodic table of the chemical elements A chemical element, or element for short, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... 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. ...

Notable characteristics

Praseodymium is a soft silvery metallic element, and belongs to the lanthanide group. It is somewhat more resistant to corrosion in air than europium, lanthanum, cerium, or neodymium, but it does develop a green oxide coating that spalls off when exposed to air, exposing more metal to oxidation. For this reason, praseodymium should be stored under a light mineral oil or sealed in glass. Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily loses electrons to form positive ions (cations) and has metallic bonds between metal atoms. ... The lanthanide series comprises the 15 elements from lanthanum to lutetium on the periodic table, with atomic numbers 57 through 71. ... Corrosion is deterioration of essential properties in a material due to reactions with its surroundings. ... General Name, Symbol, Number europium, Eu, 63 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 151. ... General Name, Symbol, Number lanthanum, La, 57 Chemical series lanthanides Group, Period, Block 3, 6, f Appearance silvery white Atomic mass 138. ... 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 neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Atomic mass 144. ... An oxide is a chemical compound containing an oxygen atom and other elements. ... Very high speed photography of a small projectile impacting a thin aluminium plate at 7000 m/s. ... The most fundamental reactions in chemistry are the redox processes. ... Mineral oil or liquid petrolatum is a by-product in the distillation of petroleum to produce gasoline. ...

Applications

Uses of praseodymium:

• As an alloying agent with magnesium to create high-strength metals that are used in aircraft engines.
• Praseodymium forms the core of carbon arc lights which are used in the motion picture industry for studio lighting and projector lights.
• Praseodymium compounds are used to give glasses and enamels a yellow color.
• Praseodymium is used to color cubic zirconia yellow-green, to simulate peridot.
• Praseodymium is a component of didymium glass, which is used to make certain types of welder's and glass blower's goggles.
• Dr. Matthew Sellars of the Laser Physics Centre at the Australian National University in Canberra, Australia slowed down a light pulse to a few hundred meters per second using praseodymium mixed with silicate crystal.
• Praseodymium alloyed with nickel (PrNi₅) has such a strong magnetocaloric effect that it has allowed scientists to approach within one thousandth of a degree of absolute zero^[1].

An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ... General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white Atomic mass 24. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... The 300,000-watt Plasma Arc Lamp in the Infrared Processing Center (IPC) at Oak Ridge National Laboratory An arc lamp is a device that produces light by the sparking (or arcing, from voltaic arc) of a high current between two carbon rod electrodes. ... A movie studio is a controlled environment for the making of a film. ... For a one-room apartment, see Apartment. ... Projectors are used for displaying an image on a projection screen or similar surface for the view of an audience. ... A chemical compound is a chemical substance consisting of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. ... 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. ... In a discussion of art technology, enamel (or vitreous enamel, or porcelain enamel in American English) is the colorful result of fusion of powdered glass to a substrate through the process of firing, usually between 750 and 850 degrees Celsius. ... Peridot (pronounced pear-uh-dot or pear-uh-doe, IPA: /pɛɹɪdɑːt/ or Fr. ... Didymium is a mixture of the elements praseodymium and neodymium. ... Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. ... A glass pipe made by lampworking Hand-blown glass beads and pendants Glassblowing is the process of forming glass into useful shapes while the glass is in a molten, semi-liquid state. ... The Australian National University, or ANU, is a public university located in Canberra, the national capital of Australia. ... Slow light is the propagation of an optical pulse or other modulation of an optical carrier at a very low group velocity. ... General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic and silvery with a gold tinge Atomic mass 58. ... Magnetic refrigeration is a cooling technology based on the magnetocaloric effect. ... Absolute zero is the lowest possible temperature where nothing could be colder, and no heat energy remains in a substance. ...

History

The name praseodymium comes from the Greek prasios, meaning green, and didymos, or twin. Praseodymium is frequently misspelled as praseodynium. Note: This page contains IPA phonetic symbols in Unicode. ...

In 1841, Mosander extracted the rare earth didymium from lanthana. In 1874, Per Teodor Cleve concluded that didymium was in fact two elements, and in 1879, Lecoq de Boisbaudran isolated a new earth, samarium, from didymium obtained from the mineral samarskite. In 1885, the Austrian chemist baron Carl Auer von Welsbach separated didymium into two elements, praseodymium and neodymium, which gave salts of different colors. Leo Moser investigated the use of praseodymium in glass coloration in the late 1920's. The result was a yellow-green glass given the name "Prasemit". However, a similar color could be achieved with colorants costing only a minute fraction of what praseodymium cost in the late 1920's, such that the color was not popular, few pieces were made, and examples are now extremely rare. Moser also blended praseodymium with neodymium to produce "Heliolite" glass ("Heliolit" in German), which was more widely accepted. The first enduring commercial use of praseodymium, which continues today, is in the form of a yellow-orange stain for ceramics, "Praseodymium Yellow", which is a solid-solution of praseodymium in the zirconium silicate (zircon) lattice. This stain has no hint of green in it. By contrast, at sufficiently high loadings, praseodymium glass is distinctly green, rather than pure yellow. Praseodymium has historically been a rare earth whose supply has exceeded demand. Unwanted as such, much praseodymium has been marketed as a mixture with lanthanum and cerium, or "LCP" for the first letters of each of the constituents, for use in replacing the traditional lanthanide mixtures that were inexpensively made from monazite or bastnaesite. LCP is what remains of such mixtures, after the desirable neodymium, and all the heavier, rarer and more valuable lanthanides have been removed, by solvent extraction. However, as technology progresses, praseodymium has been found possible to incorporate into neodymium-iron-boron magnets, thereby extending the supply of the much in demand neodymium. So LC is starting to replace LCP as a result. 1841 is a common year starting on Friday (link will take you to calendar). ... Didymium is a mixture of the elements praseodymium and neodymium. ... Lanthanum(III) oxide is La2O3, a chemical compound containing the rare earth lanthanum and oxygen. ... Year 1874 (MDCCCLXXIV) was a common year starting on Thursday (link with display the full calendar) of the Gregorian calendar (or a common year starting on Saturday of the 12-day slower Julian calendar). ... Per Teodor Cleve (Stockholm February 10, 1840 – Uppsala June 18, 1905) was a Swedish chemist and geologist. ... 1879 (MDCCCLXXIX) was a common year starting on Wednesday (see link for calendar). ... Paul Émile (François) Lecoq de Boisbaudran (April 18, 1838 - May 28, 1912) was a French chemist born in Cognac. ... General Name, Symbol, Number samarium, Sm, 62 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 150. ... Samarskite is a radioactive mineral with the empirical formula of Categories: Mineral stubs | Minerals ... 1885 (MDCCCLXXXV) is a common year starting on Thursday of the Gregorian calendar (or a common year starting on Saturday of the 12-day slower Julian calendar). ... A chemist pours from a round-bottom flask. ... Carl Auer von Welsbach ( 9 September 1858 - 8 April 1929) was an Austrian scientist and inventor who had a talent for not only discovering advances, but turning them into commercially successful products. ... General Name, Symbol, Number neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Atomic mass 144. ... A magnified crystal of a salt (halite/sodium chloride) Salt covering the floor of Bad Water in Death Valley, CA, the lowest point in the US. A salt, in chemistry, is any ionic compound composed of cations (positively charged ions) and anions (negative ions) so that the product is neutral... Color is an important part of the visual arts. ...

Occurrence

Praseodymium is available in small quantities in Earth’s crust (9.5 ppm). It is found in the rare earth minerals monazite and bastnasite, typically comprising about 5% of the lanthanides contained therein, and can be recovered from bastnasite or monazite by an ion exchange process, or by counter-current solvent extraction. Parts per million (ppm) is a measure of concentration that is used where low levels of concentration are significant. ... 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. ... Ion exchange is a process in which ions are exchanged between a solution and an ion exchanger, an insoluble solid or gel. ...

Praseodymium also makes up about 5% of misch metal. Mischmetal (from German: Mischmetall - mixed metals) is a pyrophoric alloy of rare earth elements in various naturally occurring proportions. ...

Compounds

Praseodymium compounds include:

• Fluorides
  • PrF₂
  • PrF₃
  • PrF₄
• Chlorides
  • PrCl₃
• Bromides
  • PrBr₃
  • Pr₂Br₅
• Iodides
  • PrI₂
  • PrI₃
  • Pr₂I₅
• Oxides
  • PrO₂
  • Pr₂O₃
• Sulfides
  • PrS
  • Pr₂S₃
• Selenides
  • PrSe
• Tellurides
  • PrTe
  • Pr₂Te₃
• Nitrides
  • PrN

See also praseodymium compounds. Fluoride is the ionic form of fluorine. ... The chloride ion is formed when the element chlorine picks up one electron to form an anion (negatively-charged ion) Cl−. The salts of hydrochloric acid HCl contain chloride ions and are also called chlorides. ... Overview Praseodymium(III) chloride (PrCl3), also known as praseodymium trichloride, is a compound of praseodymium and chlorine. ... A bromide is a phrase, or person who uses phrases, which have been used and repeated so many times as to become either insincere in their meaning, or seem like an attempt at trying to explain the obvious. ... An iodide ion is an iodine atom with a −1 (negative one) charge. ... An oxide is a chemical compound containing an oxygen atom and other elements. ... Formally, sulfide is the dianion, S2−, which exists in strongly alkaline aqueous solutions formed from H2S or alkali metal salts such as Li2S, Na2S, and K2S. Sulfide is exceptionally basic and, with a pKa > 14, it does not exist in appreciable concentrations even in highly alkaline water. ... The selenide ion is Se2-. A selenide is a chemical compound in which selenium serves as a anion with oxidation number of -2, much as sulfur does in a sulfide. ... Telluride is either: A compound of a metal with the element Tellurium. ... Definition The nitride ion is very very gay and retarded A nitride (compound) is a compound that has nitrogen with more electropositive elements. ...

Isotopes

Naturally occurring praseodymium is composed of one stable isotope, ¹⁴¹Pr. Thirty-eight radioisotopes have been characterized with the most stable being ¹⁴³Pr with a half-life of 13.57 days and ¹⁴²Pr with a half-life of 19.12 hours. All of the remaining radioactive isotopes have half-lives that are less than 5.985 hours and the majority of these have half-lives that are less than 33 seconds. This element also has six meta states with the most stable being ^138mPr (t_½ 2.12 hours), ^142mPr (t_½ 14.6 minutes) and ^134mPr (t_½ 11 minutes). Isotopes are any of the several different forms of an element each having different atomic mass (mass number). ... 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. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... 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 praseodymium range in atomic weight from 120.955 u (¹²¹Pr) to 158.955 u (¹⁵⁹Pr). The primary decay mode before the stable isotope, ¹⁴¹Pr, is electron capture and the primary mode after is beta minus decay. The primary decay products before ¹⁴¹Pr are element 58 (cerium) isotopes and the primary products after are element 60 (neodymium) isotopes. ... The unified atomic mass unit (u), or Dalton (Da), is a small unit of mass used to express atomic and molecular masses. ... In physics, the decay mode describes a particular way a particle decays. ... 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... 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. ... 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. ... 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 neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Atomic mass 144. ...

Precautions

Like all rare earths, praseodymium is of low to moderate toxicity. Praseodymium has no known biological role.

References

1. ^ Emsley, John (2001). NATURE'S BUILDING BLOCKS. Oxford University Press, pp. 342. ISBN 0-1985-0341-5. 

• Los Alamos National Laboratory – Praseodymium

Oxford University Press (OUP) is a highly-respected publishing house and a department of the University of Oxford in England. ...

External links

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• It's Elemental – The Element Praseodymium

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