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GadoliniumAn overview

ContentsArticlesOverview 1

Gadolinium 1

Isotopes 9

Isotopes of gadolinium 9

Miscellany 13

ReferencesArticle Sources and Contributors 14Image Sources, Licenses and Contributors 15

Article LicensesLicense 16

1

Overview

Gadolinium

Gadolinium

Appearance

silvery white

General properties

Name, symbol, number gadolinium, Gd, 64

Pronunciation /ˌɡædɵˈlɪniəm/gad-o-lin-ee-əm

Element category lanthanide

Group, period, block n/a, 6, f

Standard atomic weight 157.25 g·mol−1

Electron configuration [Xe] 4f7 5d1 6s2

Electrons per shell 2, 8, 18, 25, 9, 2 (Image)

Physical properties

Phase solid

Density (near r.t.) 7.90 g·cm−3

Liquid density at m.p. 7.4 g·cm−3

Melting point 1585 K,1312 °C,2394 °F

Boiling point 3546 K,3273 °C,5923 °F

Heat of fusion 10.05 kJ·mol−1

Heat of vaporization 301.3 kJ·mol−1

Specific heat capacity (25 °C) 37.03 J·mol−1·K−1

Vapor pressure (calculated)

P/Pa 1 10 100 1 k 10 k 100 k

at T/K 1836 2028 2267 2573 2976 3535

Atomic properties

Oxidation states 1, 2, 3 (mildly basic oxide)

Gadolinium 2

Electronegativity 1.20 (Pauling scale)

Ionization energies 1st: 593.4 kJ·mol−1

2nd: 1170 kJ·mol−1

3rd: 1990 kJ·mol−1

Atomic radius 180 pm

Covalent radius 196±6 pm

Miscellanea

Crystal structure hexagonal

Magnetic ordering ferromagnetic/paramagnetictransition at 293.4 K

Electrical resistivity (r.t.) (α, poly) 1.310 µΩ·m

Thermal conductivity (300 K) 10.6 W·m−1·K−1

Thermal expansion (100 °C, α, poly) 9.4 µm/(m·K)

Speed of sound (thin rod) (20 °C) 2680 m/s

Young's modulus (α form) 54.8 GPa

Shear modulus (α form) 21.8 GPa

Bulk modulus (α form) 37.9 GPa

Poisson ratio (α form) 0.259

Vickers hardness 570 MPa

CAS registry number 7440-54-2

Most stable isotopes

iso NA half-life DM DE (MeV) DP

152Gd 0.20% 1.08×1014 y α 2.205 148Sm

154Gd 2.18% 154Gd is stable with 90 neutron

155Gd 14.80% 155Gd is stable with 91 neutron

156Gd 20.47% 156Gd is stable with 92 neutron

157Gd 15.65% 157Gd is stable with 93 neutron

158Gd 24.84% 158Gd is stable with 94 neutron

160Gd 21.86% >1.3×1021y β−β− 1.7 160Dy

Gadolinium (  /ˌɡædɵˈlɪniəm/ gad-o-lin-ee-əm) is a chemical element with the symbol Gd and atomic number64. It is a silvery-white, malleable and ductile rare-earth metal. It is found in nature only in combined (salt) form.Gadolinium was first detected spectroscopically in 1880 by de Marignac who separated its oxide and is credited withits discovery. It is named for gadolinite, one of the minerals in which it was found, in turn named for geologist JohanGadolin. The metal was isolated by Lecoq de Boisbaudran in 1886.Gadolinium metal possesses unusual metallurgic properties, with as little as 1% of gadolinium improving the workability and resistance of iron, chromium, and related alloys to high temperatures and oxidation. Gadolinium as a metal or salt has exceptionally high absorption of neutrons and therefore is used for shielding in neutron radiography

Gadolinium 3

and in nuclear reactors. Like most rare earths, gadolinium forms trivalent ions which have fluorescent properties. Gd(III) salts have therefore been used as green phosphors in various applications.The Gd(III) ion occurring in water-soluble salts is quite toxic to mammals. However, chelated Gd(III) compoundsare far less toxic because they carry Gd(III) through the kidneys and out of the body before the free ion can bereleased into tissue. Because of its paramagnetic properties, solutions of chelated organic gadolinium complexes areused as intravenously administered gadolinium-based MRI contrast agents in medical magnetic resonance imaging.However, in a small minority of patients with renal failure, at least four such agents have been associated withdevelopment of the rare nodular inflammatory disease nephrogenic systemic fibrosis. This is thought to be due togadolinium ion itself, since Gd(III) carrier molecules associated with the disease differ.

Characteristics

A sample of gadolinium

Physical properties

Gadolinium is a silvery-white malleable and ductile rare-earth metal. Itcrystallizes in hexagonal, close-packed α- form at room temperature,but, when heated to temperatures above 1235 °C, it transforms into itsβ- form, which has a body-centered cubic structure.[1]

Gadolinium-157 has the highest thermal neutron capture cross-sectionamong any stable nuclides: 259,000 barns. Only xenon-135 has ahigher cross section, 2 million barns, but that isotope is unstable.[2]

Gadolinium is ferromagnetic at temperatures below 20 °C (68 °F)[3]

and is strongly paramagnetic above this temperature. Gadoliniumdemonstrates a magnetocaloric effect whereby its temperatureincreases when it enters a magnetic field and decreases when it leaves

the magnetic field. The effect is considerably stronger for the gadolinium alloy Gd5(Si2Ge2).[4]

Individual gadolinium atoms have been isolated by encapsulating them into fullerene molecules and visualized withtransmission electron microscope.[5] Individual Gd atoms and small Gd clusters have also been incorporated intocarbon nanotubes.[6]

Chemical propertiesGadolinium combines with most elements to form Gd(III) derivatives. nitrogen, carbon, sulfur, phosphorus, boron,selenium, silicon and arsenic at elevated temperatures, forming binary compounds.[7]

Unlike other rare earth elements, metallic gadolinium is relatively stable in dry air. However, it tarnishes quickly inmoist air, forming a loosely adhering gadolinium(III) oxide (Gd2O3), which spalls off, exposing more surface tooxidation.

4 Gd + 3 O2 → 2 Gd2O3Gadolinium is a strong reducing agent, which reduces oxides of several metals into their elements. Gadolinium isquite electropositive and reacts slowly with cold water and quite quickly with hot water to form gadoliniumhydroxide:

2 Gd + 6 H2O → 2 Gd(OH)3 + 3 H2Gadolinium metal is attacked readily by dilute sulfuric acid to form solutions containing the colorless Gd(III) ions,which exist as a [Gd(OH2)9]3+ complexes:[8]

2 Gd + 3 H2SO4 + 18 H2O → 2 [Gd(H2O)9]3+ + 3 SO42- + 3 H2

Gadolinium 4

Gadolinium metal reacts with the halogens (X2) at temperature about 200 °C:2 Gd + 3 X2 → 2 GdX3

Chemical compounds

In the great majority of its compounds, Gd adopts the oxidation state +3. All four trihalides are known. All are whiteexcept for the iodide, which is yellow. Most commonly encountered of the halides is gadolinium(III) chloride(GdCl3). The oxide dissolves in acids to give the salts, such as gadolinium(III) nitrate.Gadolinium(III), like most lanthanide ions, forms complexes with high coordination numbers. This tendency isillustrated by the use of the chelating agent DOTA, an octadentate ligand. Salts of [Gd(DOTA)]- are useful inmagnetic resonance imaging. A variety of related chelate complexes have been developed, including gadodiamide.Reduced gadolinium compounds are known, especially in the solid state. Gadolinium(II) halides are obtained byheating Gd(III) halides in presence of metallic Gd in tantalum containers. Gadolinium also form sesquichlorideGd2Cl3, which can be further reduced to GdCl by annealing at 800 °C. This gadolinium(I) chloride forms plateletswith layered graphite-like structure.[9]

IsotopesNaturally occurring gadolinium is composed of 6 stable isotopes, 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and 160Gd, and1 radioisotope, 152Gd, with 158Gd being the most abundant (24.84% natural abundance). The predicted double betadecay of 160Gd has never been observed (the only lower limit on its half-life of more than 1.3×1021 years has beenset experimentally [10] ).Twenty-nine radioisotopes have been characterized, with the most stable being alpha-decaying 152Gd (naturallyoccurring) with a half-life of 1.08×1014 years, and 150Gd with a half-life of 1.79×106 years. All of the remainingradioactive isotopes have half-lives of less than 74.7 years. The majority of these have half-lives of less than 24.6seconds. Gadolinium isotopes have 4 metastable isomers, with the most stable being 143mGd (T½=110 seconds),145mGd (T½=85 seconds) and 141mGd (T½=24.5 seconds).Isotopes with atomic masses lower than the most abundant stable isotope, 158Gd, primarily decay via electroncapture to Eu (europium) isotopes. At higher atomic masses, the primary decay mode is beta decay, and the primaryproducts are Tb (terbium) isotopes.

HistoryGadolinium is named from the mineral gadolinite, in turn named for Finnish chemist and geologist Johan Gadolin.[1]

In 1880, Swiss chemist Jean Charles Galissard de Marignac observed spectroscopic lines due to gadolinium insamples of didymium and gadolinite, and separated from them "gadolinia," gadolinium oxide. Because he realizedthat gadolinia was the oxide of a new element, he is credited with discovery of gadolinium. French chemist PaulÉmile Lecoq de Boisbaudran carried out the separation of gadolinium metal from the oxide in 1886.

Gadolinium 5

Occurrence

Gadolinite

Gadolinium is a constituent in many minerals such as monazite andbastnäsite, which are oxides. The metal is too reactive to existnaturally. Ironically, the mineral gadolinite contains only traces of Gd.The abundance in the earth crust is about 6.2 mg/kg.[1] The mainmining areas are China, USA, Brazil, Sri Lanka, India and Australiawith reserves expected to exceed one million tonnes. World productionof pure gadolinium is about 400 tonnes per year.

Production

Gadolinium is produced both from monazite and bastnäsite.

1. Crushed minerals are extracted with hydrochloric or sulfuric acids, which converts the insoluble oxides intosoluble chlorides or sulfates.

2. The acidic filtrates are partially neutralized with caustic soda to pH 3–4. Thorium precipitates as its hydroxideand is removed.

3. The remaining solution is treated with ammonium oxalate to convert rare earths in to their insoluble oxalates. Theoxalates are converted to oxides by heating.

4. The oxides are dissolved in nitric acid that excludes one of the main components, cerium, whose oxide isinsoluble in HNO3.

5. The solution is treated with magnesium nitrate to produce a crystallized mixture of double salts of gadolinium,samarium and europium.

6. The salts are separated by ion exchange chromatography.7. The rare earth ions are then selectively washed out by suitable complexing agent.[1]

Gadolinium metal is obtained from its oxide or salts by heating with calcium at 1450 °C under argon atmosphere.Sponge gadolinium can be produced by reducing molten GdCl3 with an appropriate metal at temperatures below1312 °C (melting point of Gd) in a reduced pressure.[1]

ApplicationsGadolinium has no large-scale applications but has a variety of specialized uses.Gadolinium has the highest neutron cross-section among any stable nuclides: 61,000 barns for 155Gd and 259,000barns for 157Gd. 157Gd has been used to target tumors in neutron therapy. This element is very effective for use withneutron radiography and in shielding of nuclear reactors. It is used as a secondary, emergency shut-down measure insome nuclear reactors, particularly of the CANDU type.[1] Gadolinium is also used in nuclear marine propulsionsystems as a burnable poison.Gadolinium also possesses unusual metallurgic properties, with as little as 1% of gadolinium improving theworkability and resistance of iron, chromium, and related alloys to high temperatures and oxidation.Gadolinium is paramagnetic at room temperature, with a ferromagnetic Curie point of 20 °C.[3] Paramagnetic ions, such as gadolinium, move differently within a magnetic field. This trait makes gadolinium useful for magnetic resonance imaging (MRI). Solutions of organic gadolinium complexes and gadolinium compounds are used as intravenous MRI contrast agent to enhance images in medical magnetic resonance imaging and magnetic resonance angiography (MRA) procedures. Magnevist is the most widespread example.[11] [12] Nanotubes packed with gadolinium, dubbed "gadonanotubes," are 40 times more effective than this traditional gadolinium contrast agent.[13]

Once injected, gadolinium-based contrast agents accumulate in abnormal tissues of the brain and body. This accumulation provides a greater contrast between normal and abnormal tissues, allowing doctors to better locate

Gadolinium 6

uncommon cell growths and tumors.

Gadolinium-153 helps calibrate positron emission tomography (PET) systemsthat are used in nuclear medicine for functional imaging. This PET image of

the human brain shows the difference between a normal brain and theclinically depressed patient. The blue color indicates less glucose metabolismin a normal brain. The green, yellow, and red colors indicate areas of higher

glucose metabolism characteristic of a depressed patient.[14]

Gadolinium as a phosphor is also used in otherimaging. In X-ray systems, gadolinium iscontained in the phosphor layer, suspended in apolymer matrix at the detector. Terbium-dopedgadolinium oxysulfide (Gd2O2S: Tb) at thephosphor layer converts the X-rays releasedfrom the source into light. This material emitsgreen light at 540 nm due to the presence ofTb3+, which is very useful for enhancing theimaging quality. The energy conversion of Gd isup to 20%, which means that one-fifth of theX-rays striking the phosphor layer can beconverted into light photons. Gadoliniumoxyorthosilicate (Gd2SiO5, GSO; usually doped by 0.1–1% of Ce) is a single crystal that is used as a scintillator inmedical imaging such as positron emission tomography or for detecting neutrons.[15]

Gadolinium compounds are also used for making green phosphors for colour TV tubes and compact discs.Gadolinium-153 is produced in a nuclear reactor from elemental europium or enriched gadolinium targets. It has ahalf-life of 240±10 days and emits gamma radiation with strong peaks at 41 keV and 102 keV. It is used in manyquality assurance applications, such as line sources and calibration phantoms, to ensure that nuclear medicineimaging systems operate correctly and produce useful images of radioisotope distribution inside the patient.[14] It isalso used as a gamma ray source in X-ray absorption measurements or in bone density gauges for osteoporosisscreening, as well as in the Lixiscope portable X-ray imaging system.[16]

Gadolinium is used for making gadolinium yttrium garnet (Gd:Y3Al5O12); it has microwave applications and is usedin fabrication of various optical components and as substrate material for magneto–optical films.Gadolinium Gallium Garnet (GGG, Gd3Ga5O12) was used for imitation diamonds and for computer bubblememory.[17]

Biological roleGadolinium has no known native biological role, but its compounds are used as research tools in biomedicine. Gd3+

compounds are components of MRI contrast agents. It is used in various ion channel electrophysiology experimentsto block sodium leak channels, as well as to stretch activated ion channels.[18]

SafetyAs a free ion, gadolinium is highly toxic, but MRI contrast agents are chelated compounds and are considered safeenough to be used in most persons. The toxicity depends on the strength of the chelating agent. About a dozendifferent Gd-chelated agents have been approved as MRI contrast agents around the world. [19] [20] [21]

Gadolinium MRI contrast agents have proved safer than the iodinated contrast agents used in X-ray radiography orcomputed tomography. Anaphylactoid reactions are rare, occurring in approx. 0.03–0.1%.[22]

Although gadolinium agents have proved useful for patients with renal impairment, in patients with severe renal failure requiring dialysis, there is a risk of a rare but serious illnesses, called nephrogenic systemic fibrosis[23] or nephrogenic fibrosing dermopathy,[24] that has been linked to the use of four gadolinium-containing MRI contrast agents. The disease resembles scleromyxedema and to some extent scleroderma. It may occur months after contrast has been injected. Its association with gadolinium and not the carrier molecule is confirmed by its occurrence in from

Gadolinium 7

contrast materials in which gadolinium is carried by very different carrier molecules.Current guidelines in the United States are that dialysis patients should only receive gadolinium agents whereessential, and that dialysis should be performed as soon as possible after the scan is complete, in order to remove theagent from the body promptly.[25]

References[1] Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0080379419.[2] "Gadolinium" (http:/ / www. ncnr. nist. gov/ resources/ n-lengths/ elements/ gd. html). Neutron News (NIST) 3 (3): 29. 1992. . Retrieved

2009-06-06.[3] Lide, D. R., ed (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. p. 4.122. ISBN 0-8493-0486-5.[4] Karl Gschneidner, Jr. and Kerry Gibson (2001-12-07). "Magnetic refrigerator successfully tested" (http:/ / www. external. ameslab. gov/

news/ release/ 01magneticrefrig. htm). Ames Laboratory. . Retrieved 2006-12-17.[5] Suenaga, Kazu; Taniguchi, Risa; Shimada, Takashi; Okazaki, Toshiya; Shinohara, Hisanori; Iijima, Sumio (2003). "Evidence for the

Intramolecular Motion of Gd Atoms in a Gd2@C92 Nanopeapod". Nano Letters 3 (10): 1395. Bibcode 2003NanoL...3.1395S.doi:10.1021/nl034621c.

[6] Hashimoto, A.; Yorimitsu, H; Ajima, K; Suenaga, K; Isobe, H; Miyawaki, J; Yudasaka, M; Iijima, S et al. (2004). "Selective deposition of agadolinium(III) cluster in a hole opening of single-wall carbon nanohorn". Proceedings of the National Academy of Sciences 101 (23):8527–30. Bibcode 2004PNAS..101.8527H. doi:10.1073/pnas.0400596101. PMC 423227. PMID 15163794.

[7] Holleman, A. F.; Wiberg, E. (2001), Inorganic Chemistry, San Diego: Academic Press, ISBN 0-12-352651-5[8] "Chemical reactions of Gadolinium" (https:/ / www. webelements. com/ gadolinium/ chemistry. html). Webelements. . Retrieved 2009-06-06.[9] Cotton (2007). Advanced inorganic chemistry, 6th ed (http:/ / books. google. com/ ?id=U3MWRONWAmMC& pg=PA1128). Wiley-India.

p. 1128. ISBN 8126513381. .[10] Danevich, F. A. et al. (2001). "Quest for double beta decay of 160Gd and Ce isotopes". Nucl. Phys. A 694: 375. arXiv:nucl-ex/0011020.

Bibcode 2001NuPhA.694..375D. doi:10.1016/S0375-9474(01)00983-6.[11] Gary Liney (2006). MRI in clinical practice (http:/ / books. google. com/ ?id=xpCffxNrCXYC& pg=PA13). Springer. pp. 13;30.

ISBN 184628161X. .[12] Kenneth N. Raymond; Valerie C. Pierre (2005). "Next Generation, High Relaxivity Gadolinium MRI Agents". Bioconjugate Chemistry 16

(1): 3–8. doi:10.1021/bc049817y. PMID 15656568.[13] Magnets Guide Stem Cells to Damaged Hearts (http:/ / www. texmedctr. tmc. edu/ root/ en/ TMCServices/ News/ 2009/ 12-01/ Magnets+

Guide+ Stem+ Cells+ to+ Damaged+ Hearts. htm) Dec, 2009[14] "Gadolinium-153" (http:/ / radioisotopes. pnl. gov/ gadolinium. stm). Pacific Northwest National Laboratory. . Retrieved 2009-06-06.[15] Ryzhikov, V. D.; Grinev, B. V.; Pirogov, E. N.; Onyshchenko, G. M.; Ivanov, A. I.; Bondar, V. G.; Katrunov, K. A.; Kostyukevich, S. A.

(2005). "Use of gadolinium oxyorthosilicate scintillators in x-ray radiometers". Optical Engineering 44: 016403.Bibcode 2005OptEn..44a6403R. doi:10.1117/1.1829713.

[16] "Lixi, Inc." (http:/ / www. ndt. net/ news/ lixi. htm). . Retrieved 2009-06-06.[17] Hammond, C. R. The Elements, in Lide, D. R., ed (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC

Press. ISBN 0-8493-0486-5.[18] Yeung, Ew; Allen, Dg (August 2004). "Stretch-activated channels in stretch-induced muscle damage: role in muscular dystrophy". Clinical

and experimental pharmacology & physiology 31 (8): 551–6. doi:10.1111/j.1440-1681.2004.04027.x. ISSN 0305-1870. PMID 15298550.[19] "Questions and Answers on Magnetic resonance imaging" (http:/ / www. ismrm. org/ special/ EMEA2. pdf). . Retrieved 2009-06-06.[20] "Information on Gadolinium-Containing Contrast Agents" (http:/ / www. fda. gov/ cder/ drug/ infopage/ gcca/ default. htm). .[21] The Elements, Theodore Gray, Black Dog & Leventhal Publishers, 2009[22] Murphy KJ, Brunberg JA, Cohan RH (1 October 1996). "Adverse reactions to gadolinium contrast media: A review of 36 cases" (http:/ /

www. ajronline. org/ cgi/ pmidlookup?view=long& pmid=8819369). AJR Am J Roentgenol 167 (4): 847–9. PMID 8819369. .[23] H.S. Thomsen, S.K. Morcos and P. Dawson (November 2006). "Is there a causal relation between the administration of gadolinium-based

contrast media and the development of nephrogenic systemic fibrosis (NSF)?". Clinical Radiology 61 (11): 905–6.doi:10.1016/j.crad.2006.09.003. PMID 17018301.

[24] Grobner T. (2006-01-23). "Gadolinium — a specific trigger for the development of nephrogenic fibrosing dermopathy and nephrogenicsystemic fibrosis?". Nephrology Dialysis Transplantation 21 (4): 1104–8. doi:10.1093/ndt/gfk062. PMID 16431890.

[25] "FDA Public Health Advisory: Gadolinium-containing Contrast Agents for Magnetic Resonance Imaging" (http:/ / www. fda. gov/ cder/drug/ advisory/ gadolinium_agents. htm). . Retrieved 2009-06-06.

Gadolinium 8

External links• Nephrogenic Systemic Fibrosis – Complication of Gadolinium MR Contrast (http:/ / rad. usuhs. edu/ medpix/

master. php3?mode=slide_sorter& pt_id=10978& quiz=#top) (series of images at MedPix website)• It's Elemental – Gadolinium (http:/ / education. jlab. org/ itselemental/ ele064. html)• Refrigerator uses gadolinium metal that heats up when exposed to magnetic field (http:/ / www. external.

ameslab. gov/ news/ release/ 01magneticrefrig. htm)• FDA advisory on gadolinium-based contrast (http:/ / www. fda. gov/ cder/ drug/ infopage/ gcca/ qa_200705. htm)• Abdominal MR imaging: important considerations for evaluation of gadolinium enhancement (http:/ / www.

siaecm. org/ gadolinium/ index. asp) Rafael O.P. de Campos, Vasco Herédia, Ersan Altun, Richard C. Semelka,Department of Radiology University of North Carolina Hospitals Chapel Hill

9

Isotopes

Isotopes of gadoliniumNaturally occurring gadolinium (Gd) is composed of 6 stable isotopes, 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and160Gd, and 1 radioisotope, 152Gd, with 158Gd being the most abundant (24.84% natural abundance). The predicteddouble beta decay of 160Gd has never been observed; only lower limit on its half-life of more than 1.3×1021 yearshas been set experimentally.[1]

Thirty radioisotopes have been characterized, with the most stable being alpha-decaying 152Gd (naturally occurring)with a half-life of 1.08×1014 years, and 150Gd with a half-life of 1.79×106 years. All of the remaining radioactiveisotopes have half-lives less than 74.7 years. The majority of these have half-lives less than 24.6 seconds.Gadolinium isotopes have 10 metastable isomers, with the most stable being 143mGd (T½=110 seconds), 145mGd(T½=85 seconds) and 141mGd (T½=24.5 seconds).The primary decay mode at atomic weights lower than the most abundant stable isotope, 158Gd, is electron capture,and the primary mode at higher atomic weights is beta decay. The primary decay products for isotopes of weightslower than 158Gd are the element Eu (europium) isotopes and the primary products at higher weights are the elementTb (terbium) isotopes.Gadolinium-153 has a half-life of 240.4±10 days and emits gamma radiation with strong peaks at 41 keV and 102keV. It is used as a gamma ray source in X-ray absorptiometry or bone density gauges for osteoporosis screening,and in the Lixiscope portable x-ray imaging system.Standard atomic mass: 157.25(3) u

Table

nuclidesymbol

Z(p) N(n) isotopic mass(u)

half-life[2] decaymode(s)[3]

[4]

daughterisotope(s)[5]

nuclearspin

representativeisotopic

composition(mole

fraction)

range ofnatural

variation(mole

fraction) excitation energy

134Gd 64 70 133.95537(43)# 0.4# s 0+

135Gd 64 71 134.95257(54)# 1.1(2) s 3/2-

136Gd 64 72 135.94734(43)# 1# s [>200ns]

β+ 136Eu

137Gd 64 73 136.94502(43)# 2.2(2) s β+ 137Eu 7/2+#

β+, p (rare) 136Sm138Gd 64 74 137.94012(21)# 4.7(9) s β+ 138Eu 0+

138mGd 2232.7(11) keV 6(1) µs (8-)

139Gd 64 75 138.93824(21)# 5.7(3) s β+ 139Eu 9/2-#

β+, p (rare) 138Sm139mGd 250(150)# keV 4.8(9) s 1/2+#

Isotopes of gadolinium 10

140Gd 64 76 139.93367(3) 15.8(4) s β+ 140Eu 0+

141Gd 64 77 140.932126(21) 14(4) s β+ (99.97%) 141Eu (1/2+)

β+, p (.03%) 140Sm141mGd 377.8(2) keV 24.5(5) s β+ (89%) 141Eu (11/2-)

IT (11%) 141Gd142Gd 64 78 141.92812(3) 70.2(6) s β+ 142Eu 0+

143Gd 64 79 142.92675(22) 39(2) s β+ 143Eu (1/2)+

β+, α (rare) 139Pm

β+, p (rare) 142Sm143mGd 152.6(5) keV 110.0(14) s β+ 143Eu (11/2-)

β+, α (rare) 139Pm

β+, p (rare) 142Sm144Gd 64 80 143.92296(3) 4.47(6) min β+ 144Eu 0+

145Gd 64 81 144.921709(20) 23.0(4) min β+ 145Eu 1/2+

145mGd 749.1(2) keV 85(3) s IT (94.3%) 145Gd 11/2-

β+ (5.7%) 145Eu146Gd 64 82 145.918311(5) 48.27(10) d EC 146Eu 0+

147Gd 64 83 146.919094(3) 38.06(12) h β+ 147Eu 7/2-

147mGd 8587.8(4) keV 510(20) ns (49/2+)

148Gd 64 84 147.918115(3) 74.6(30) a α 144Sm 0+

β+β+ (rare) 148Sm

149Gd 64 85 148.919341(4) 9.28(10) d β+ 149Eu 7/2-

α(4.34×10−4%)

145Sm

150Gd 64 86 149.918659(7) 1.79(8)×106

a α 146Sm 0+

β+β+ (rare) 150Sm

151Gd 64 87 150.920348(4) 124(1) d EC 151Eu 7/2-

α (10−6%) 147Sm

152Gd[6] 64 88 151.9197910(27)

1.08(8)×1014

a

α 148Sm 0+ 0.0020(1)

153Gd 64 89 152.9217495(27)

240.4(10) d EC 153Eu 3/2-

Isotopes of gadolinium 11

153m1Gd 95.1737(12) keV 3.5(4) µs (9/2+)

153m2Gd 171.189(5) keV 76.0(14) µs (11/2-)

154Gd 64 90 153.9208656(27)

Observationally Stable[7] 0+ 0.0218(3)

155Gd[8] 64 91 154.9226220(27)

Observationally Stable[9] 3/2- 0.1480(12)

155mGd 121.05(19) keV 31.97(27)ms

IT 155Gd 11/2-

156Gd[8] 64 92 155.9221227(27)

Observationally Stable[10] 0+ 0.2047(9)

156mGd 2137.60(5) keV 1.3(1) µs 7-

157Gd[8] 64 93 156.9239601(27)

Observationally Stable[10] 3/2- 0.1565(2)

158Gd[8] 64 94 157.9241039(27)

Observationally Stable[10] 0+ 0.2484(7)

159Gd[8] 64 95 158.9263887(27)

18.479(4) h β- 159Tb 3/2-

160Gd[8] 64 96 159.9270541(27)

Observationally Stable[11] 0+ 0.2186(19)

161Gd 64 97 160.9296692(29)

3.646(3) min β- 161Tb 5/2-

162Gd 64 98 161.930985(5) 8.4(2) min β- 162Tb 0+

163Gd 64 99 162.93399(32)# 68(3) s β- 163Tb 7/2+#

164Gd 64 100 163.93586(43)# 45(3) s β- 164Tb 0+

165Gd 64 101 164.93938(54)# 10.3(16) s β- 165Tb 1/2-#

166Gd 64 102 165.94160(64)# 4.8(10) s β- 166Tb 0+

167Gd 64 103 166.94557(64)# 3# s β- 167Tb 5/2-#

168Gd 64 104 167.94836(75)# 300# ms β- 168Tb 0+

169Gd 64 105 168.95287(86)# 1# s β- 169Tb 7/2-#

[1] F. A. Danevich et al. (2001). "Quest for double beta decay of 160Gd and Ce isotopes". Nuclear Physics A 694: 375. arXiv:nucl-ex/0011020.Bibcode 2001NuPhA.694..375D. doi:10.1016/S0375-9474(01)00983-6.

[2] Bold for isotopes with half-lives longer than the age of the universe (nearly stable)

Isotopes of gadolinium 12

[3] http:/ / www. nucleonica. net/ unc. aspx[4] Abbreviations:

EC: Electron captureIT: Isomeric transition

[5] Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe)[6] primordial radionuclide[7] Believed to undergo α decay to 150Sm[8] Fission product[9] Believed to undergo α decay to 151Sm[10] Theoretically capable of spontaneous fission[11] Believed to undergo β-β- decay to 160Dy with a half-life over 1.3×1021 years

Notes• Geologically exceptional samples are known in which the isotopic composition lies outside the reported range.

The uncertainty in the atomic mass may exceed the stated value for such specimens.• Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins

with weak assignment arguments are enclosed in parentheses.• Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values

denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which useexpanded uncertainties.

References• Isotope masses from:

• G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclearand decay properties" (http:/ / www. nndc. bnl. gov/ amdc/ nubase/ Nubase2003. pdf). Nuclear Physics A 729:3–128. Bibcode 2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.

• Isotopic compositions and standard atomic masses from:• J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor

(2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)" (http:/ / www. iupac. org/publications/ pac/ 75/ 6/ 0683/ pdf/ ). Pure and Applied Chemistry 75 (6): 683–800.doi:10.1351/pac200375060683.

• M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)" (http:/ / iupac. org/publications/ pac/ 78/ 11/ 2051/ pdf/ ). Pure and Applied Chemistry 78 (11): 2051–2066.doi:10.1351/pac200678112051. Lay summary (http:/ / old. iupac. org/ news/ archives/ 2005/atomic-weights_revised05. html).

• Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.• G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear

and decay properties" (http:/ / www. nndc. bnl. gov/ amdc/ nubase/ Nubase2003. pdf). Nuclear Physics A 729:3–128. Bibcode 2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.

• National Nuclear Data Center. "NuDat 2.1 database" (http:/ / www. nndc. bnl. gov/ nudat2/ ). BrookhavenNational Laboratory. Retrieved September 2005.

• N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85thed.). CRC Press. Section 11. ISBN 978-0849304859.

13

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Article Sources and ContributorsGadolinium  Source: http://en.wikipedia.org/w/index.php?oldid=464297537  Contributors: (jarbarf), 2over0, A876, AXRL, Ageoflo, Ahoerstemeier, AlimanRuna, Anypodetos, Archimerged,Ariel., Arjen Dijksman, Arkuat, B00P, Baccyak4H, Benbest, Bento00, Blathnaid, BlueEarth, Borislav Dopudja, Brendan Moody, Brian Huffman, Bruinfan12, Bryan Derksen, CaptainVindaloo,Carnildo, Ceyockey, Chem-awb, Chemicalinterest, Closedmouth, Communisthamster, Conversion script, Cybercobra, DSachan, Danielle dk, Darrien, David Latapie, Db099221, Deflective,Diwas, Dmn, Drphilharmonic, Duffman, DynamoDegsy, Eddideigel, Edgar181, EinderiheN, Element16, Emperorbma, Evil saltine, Expatinsweden, Facts707, Femto, Fleela, Foobar, Gap9551,Gene Nygaard, GraemeL, Graham87, GregorB, Grendelkhan, Groyolo, Gypsypkd, Hallpriest9, Hankwang, Hardy42, Hdt83, Helge Skjeveland, Hermitian, Hippiejesus, Icairns, Ideyal, IvanLanin,J.N., Jaan513, Jahibadkaret, Jaraalbe, JazHambo, Jfdwolff, Jj137, Jmknox, Joanjoc, JoeBruno, John, Jose77, Julesd, Kaneko ed, Karl-Henner, Kbrose, Kevin Hughes, Khazar, Kostisl, Kurykh,Kwamikagami, LA2, Lanthanum-138, LeyteWolfer, Looxix, LuigiManiac, Mac addict, Marc Venot, Mashford, Materialscientist, Mav, Michael L. Hall, Mikael Häggström, Mikespedia,Minesweeper, Mriphysician, Mtodorov 69, Nedim Ardoğa, Neparis, Nergaal, Nij90, Nimur, Noobeditor, Nsaa, Patstuart, PeepP, Peterl, Phil Boswell, Physics138, Pika32141, Plasticup, Plexust,Polyamorph, Poolkris, Powernick50, Psyche825, RTC, Rapscallion, Remember, Rholton, Rich Farmbrough, Rjwilmsi, Robert Foley, Robert K S, Roberta F., Romanm, Rrumary, Santăr,Saperaud, SauliH, Sbharris, Sbyrnes321, Schneelocke, Selket, Sengkang, Seraphimblade, Seungfire, Sfuerst, Shaddack, Shinkolobwe, Shjacks45, Shoefly, Sionus, Sl, Sleigh, Smokefoot,Someone else, Spinningspark, Stan J Klimas, Stemonitis, Steve Hart, Stifynsemons, Stone, Strait, SunCreator, Swpb, TGCP, Tagishsimon, Tetracube, Tgeairn, Thumperward, Tkstark, V1adis1av,Vsmith, Vuo, Vyomparashar, Walkerma, Watch37264, Wavelength, Weihao.chiu, Wiki alf, Xeworlebi, Xiggelee, Yekrats, Yyy, Zereshk, 191 anonymous edits

Isotopes of gadolinium  Source: http://en.wikipedia.org/w/index.php?oldid=451796412  Contributors: Bryan Derksen, Donarreiskoffer, Femto, Headbomb, Hqb, John, Limulus, Rjwilmsi, Strait,V1adis1av, XinaNicole, 3 ,حسن علي البط anonymous edits

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