Neptunium

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Neptunium Quick Reference

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Notes

Symbol

Np

Atomic Number

93

Oxidation States

7

less common

6

less common

5

more common

4

less common

3

less common

2

less common

Pauling Electronegativity

1.36

Electron Configuration

Orbital Occupancy

[Rn] 5f4 6d1 7s2

[Rn] represents the closed-shell electron configuration of radon

Orbital Filling Order

[Rn] 7s2 5f4 6d1

[Rn] represents the closed-shell electron configuration of radon

Term Symbol

6L11/2

see expanded configuration ...

Ionization Energies

I (1)

6.2657 eV

Density

solid, 25 °C

20.200 g/cm3

Molar Volume

solid, 298 K, 1 atm

11.59 cm3/mol

Melting Point

913 ± 3 K

Boiling Point

3902 C

Thermal Conductivity

solid, 300 K, polycrystalline

6.3 W/(m K)

estimated

Pyykkö Covalent Radius

single bond

171 pm

double bond

136 pm

triple bond

116 pm

Atomic Radius

140 pm

Enthalpy of Fusion

1 atm

9.46 kJ/mol

Enthalpy of Vaporization

1 atm

336.6 kJ/mol

Quantity

Neptunium Atomic Structure

Notes

Ionization Energies

I (1)

6.2657 eV

Electron Binding Energies

K    (1s)

118669 ± 5 eV

LI   (2s)

 22427 ± 2 eV

LII  (2p1/2)

 21600 ± 1 eV

LIII (2p3/2)

 17610 ± 1 eV

see all 24 energies ...

Electron Configuration

Orbital Occupancy

[Rn] 5f4 6d1 7s2

[Rn] represents the closed-shell electron configuration of radon

Orbital Filling Order

[Rn] 7s2 5f4 6d1

[Rn] represents the closed-shell electron configuration of radon

Term Symbol

6L11/2

see expanded configuration ...

Fluorescence Yields

ωK

0.971

ωL1

0.2  

ωL2

0.519

ωL3

0.454

Coster-Kronig Yields

F12

0.03 

F13

0.67 

F23

0.136

Quantity

Neptunium Physical Properties

Notes

Density

solid, 25 °C

20.200 g/cm3

Molar Volume

solid, 298 K, 1 atm

11.59 cm3/mol

Physical Form

silvery metal

Young's Modulus

68.0 GPa

Electrical Resistivity

solid, 295 K

118×10-8 Ohm m

Isothermal Bulk Modulus

300 K

68 GPa

estimated

Isothermal Compressibility

300 K

0.015 GPa-1

estimated

Quantity

Neptunium Atomic Interaction

Notes

Oxidation States

7

less common

6

less common

5

more common

4

less common

3

less common

2

less common

Pauling Electronegativity

1.36

Allred-Rochow Electronegativity

1.22

Allred Electronegativity

oxidation state: 2

1.36

Nagle Electronegativity

1.09

Cohesive Energy

per mole

456 kJ/mol    

per atom

  4.73 eV/atom

Quantity

Neptunium Thermodynamics

Notes

Melting Point

913 ± 3 K

Boiling Point

3902 C

Thermal Conductivity

solid, 300 K, polycrystalline

6.3 W/(m K)

estimated

Critical Point

12000 K

Enthalpy of Fusion

1 atm

9.46 kJ/mol

Enthalpy of Vaporization

1 atm

336.6 kJ/mol

Electronic Heat Capacity Coefficient

13.7 mJ/(mol K2)

Debye Temperature

Low Temperature Limit ( 0 K )

259 K

Room Temperature ( 298 K )

163 K

Quantity

Neptunium Identification

Notes

CAS Number

7439-99-8

Quantity

Neptunium Atomic Size

Notes

Atomic Radius

140 pm

Orbital Radius

174.1 pm

Pyykkö Covalent Radius

single bond

171 pm

double bond

136 pm

triple bond

116 pm

Cordero Covalent Radius

190 pm

Shannon-Prewitt Crystal Radius

ion charge: +2, coordination number: 6

124 pm

ion charge: +3, coordination number: 6

115 pm

ion charge: +4

coordination number: 6

101 pm

coordination number: 8

112 pm

ion charge: +5, coordination number: 6

 89 pm

ion charge: +6, coordination number: 6

 86 pm

ion charge: +7, coordination number: 6

 85 pm

Shannon-Prewitt Effective Ionic Radius

ion charge: +2, coordination number: 6

110 pm

ion charge: +3, coordination number: 6

101 pm

ion charge: +4

coordination number: 6

 87 pm

coordination number: 8

 98 pm

ion charge: +5, coordination number: 6

 75 pm

ion charge: +6, coordination number: 6

 72 pm

ion charge: +7, coordination number: 6

 71 pm

Pauling Empirical Crystal Radius

ion charge: +4

 95 pm

ion charge: +3

109 pm

Slater Atomic-Ionic Radius

175 pm

Quantity

Neptunium Crystal Structure

Notes

Allotropes

allotrope

α-neptunium

symbol

αNp

allotrope

β-neptunium

symbol

βNp

allotrope

γ-neptunium

symbol

γNp

Nearest Neighbor Distance

300 K, 1 atm

262 pm

Atomic Concentration

300 K, 1 atm

5.20×1022 cm-3

Quantity

Neptunium History

Notes

Discovery

date of discovery

1940

discoverer

Edwin Mattison McMillan

birth

September 18, 1907

death

September 7, 1991

discoverer

Philip Hauge Abelson

birth

1913

death

August 1, 2004

location of discovery

Berkeley, California

Origin of Element Name

origin

Neptune

origin description

celestial body—Planet

Origin of Element Symbol

symbol: Np

origin

neptunium

origin description

element name

Quantity

Neptunium Nomenclature

Notes

Element Names in Other Languages

French

neptunium

German

Neptunium

Italian

nettunio

Spanish

neptunio

Portuguese

neptúnio

Anions or Anionic Substituent Groups

neptunide

Cations or Cationic Substituent Groups

neptunium

Ligands

neptunido

Heteroatomic Anion

neptunate

'a' Term—Substitutive Nomenclature

neptuna

'y' Term—Chains and Rings Nomenclature

neptuny

References    (Click the button next to a value above to see complete citation information for that entry)

Allred, A. L. "Electronegativity Values from Thermochemical Data." Journal of Inorganic and Nuclear Chemistry, volume 17, number 3-4, 1961, pp. 215–221. doi:10.1016/0022-1902(61)80142-5

Campbell, J. L. "Fluorescence Yields and Coster–Kronig Probabilities for the Atomic L Subshells. Part II: The L1 Subshell Revisited." Atomic Data and Nuclear Data Tables, volume 95, number 1, 2009, pp. 115–124. doi:10.1016/j.adt.2008.08.002

Campbell, J. L. "Fluorescence Yields and Coster–Kronig Probabilities for the Atomic L Subshells." Atomic Data and Nuclear Data Tables, volume 85, number 2, 2003, pp. 291–315. doi:10.1016/S0092-640X(03)00059-7

Cardarelli, François. Materials Handbook: A Concise Desktop Reference, 2nd edition. London: Springer–Verlag, 2008.

Connelly, Neil G., Ture Damhus, Richard M. Hartshorn, and Alan T. Hutton. Nomenclature of Inorganic Chemistry: IUPAC Recommendations 2005. Cambridge: RSC Publishing, 2005.

Cordero, Beatriz, Verónica Gómez, Ana E. Platero-Prats, Marc Revés, Jorge Echeverría, Eduard Cremades, Flavia Barragán, and Santiago Alvarez. "Covalent Radii Revisited." Dalton Transactions, number 21, 2008, pp 2832–2838. doi:10.1039/b801115j

Cox, P. A. The Elements: Their Origin, Abundance and Distribution. Oxford: Oxford University Press, 1989.

de Podesta, Michael. Understanding the Properties of Matter, 2nd edition. London: Taylor & Francis, 2002.

Donohue, Jerry. The Structures Of The Elements, 2nd edition. Malabar, Florida: Robert E. Krieger Publishing Company, 1974.

Dronskowski, Richard. Computational Chemistry of Solid State Materials. Weinheim, Germany: WILEY-VCH Verlag GmbH & Co. KGaA, 2005.

Emsley, John. Nature's Building Blocks: An A-Z Guide to the Elements. Oxford: Oxford University Press, 2003.

Emsley, John. The Elements, 3rd edition. Oxford: Oxford University Press, 1998.

Firestone, Richard B. Table of Isotopes, 8th edition, volume 2. Edited by Virginia S. Shirley, with assistant editors Coral M. Baglin, S. Y. Frank Chu, and Jean Zipkin. New York: John Wiley & Sons, Inc., 1996.

Greenwood, N. N., and A. Earnshaw. Chemistry of the Elements, 2nd edition. Burlington, MA: Butterworth-Heinemann, 1997.

Greenwood, N. N., and A. Earnshaw. Chemistry of the Elements, 2nd edition. Oxford: Butterworth-Heinemann, 1997.

Ho, C. Y., R. W. Powell, and P. E. Liley. "Thermal Conductivity of the Elements: A Comprehensive Review." Journal of Physical and Chemical Reference Data, volume 3, supplement 1, 1974, pp. I–1 to I–796.

Horvath, A. L. "Critical Temperature of Elements and the Periodic System." Journal of Chemical Education, volume 50, number 5, 1973, pp. 335–336. doi:10.1021/ed050p335

Huheey, James E., Ellen A. Keiter, and Richard L Keiter. Inorganic Chemistry: Principles of Structure and Reactivity, 4th edition. New York: HarperCollins College Publishers, 1993.

Ihde, Aaron J. The Development of Modern Chemistry. New York: Dover Publications, Inc., 1984.

Indelicato, P., J. P. Santos, S. Boucard, and J.-P. Desclaux. "QED and Relativistic Corrections in Superheavy Elements." The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics, volume 45, number 1, 2007, pp. 155–170. doi:10.1140/epjd/e2007-00229-y

Jr., Elbert J. Little,, and Mark M. Jones. "A Complete Table of Electronegativities." Journal of Chemical Education, volume 37, number 5, 1960, pp. 231–233. doi:10.1021/ed037p231

Kaltsoyannis, Nikolas, and Peter Scott. The f Elements. Oxford: Oxford University Press, 1999.

Kennedy, Donald. "In Memoriam: Philip Hauge Abelson, 1913-2004." Science, volume 305, number 5685, 2004, p. 765. doi:10.1126/science.305.5685.765

King, H. W. "Temperature-Dependent Allotropic Structures of the Elements." Bulletin of Alloy Phase Diagrams, volume 3, number 2, 1982, pp. 275–276. doi:10.1007/BF02892394

Kittel, Charles. Introduction to Solid State Physics, 8th edition. Hoboken, NJ: John Wiley & Sons, Inc, 2005.

Konings, Rudy J. M., and Ondrej Beneš. "The Thermodynamic Properties of the f-Elements and Their Compounds. I. The Lanthanide and Actinide Metals." Journal of Physical and Chemical Reference Data, volume 39, number 4, 2010, pp. 043102–1 to 043102–47. doi:10.1063/1.3474238

Lide, David R., editor. CRC Handbook of Chemistry and Physics, 88th edition. Boca Raton, Florida: Taylor & Francis Group, 2008.

Marshall, James L. Discovery of the Elements: A Search for the Fundamental Principles of the Universe, 2nd edition. Boston, MA: Pearson Custom Publishing, 2002.

Martin, W. C. "Electronic Structure of the Elements." The European Physical Journal C — Particles and Fields, volume 15, number 1–4, 2000, pp. 78–79. doi:10.1007/BF02683401

Miessler, Gary L., and Donald A. Tarr. Inorganic Chemistry, 3rd edition. Upper Saddle River, NJ: Pearson Prentice Hall, 2004.

Nagle, Jeffrey K. "Atomic Polarizability and Electronegativity." Journal of the American Chemical Society, volume 112, number 12, 1990, pp. 4741–4747. doi:10.1021/ja00168a019

Nobel Foundation. Edwin M. McMillan: The Nobel Prize in Chemistry 1951. http://nobelprize.org/nobel_prizes/chemistry/laureates/1951/mcmillan-bio.html. Accessed on July 1, 2009.

Oxtoby, David W., H. P. Gillis, and Alan Campion. Principles of Modern Chemistry, 6th edition. Belmont, CA: Thomson Brooks/Cole, 2008.

Pauling, Linus. The Nature of the Chemical Bond, 3rd edition. Ithaca, NY: Cornell University Press, 1960.

Pekka Pyykkö. Self-Consistent, Year-2009 Covalent Radii. http://www.chem.helsinki.fi/~pyykko/Radii09.pdf. Accessed on November 20, 2010.

Porter, F.T., and M. S. Freedman. "Recommended Atomic Electron Binding Energies, 1s to 6p3/2, for the Heavy Elements, Z = 84 to 103." Journal of Physical and Chemical Reference Data, volume 7, number 4, 1978, pp. 1267–1284.

Pyykkö, Pekka, and Michiko Atsumi. "Molecular Double-Bond Covalent Radii for Elements Li-E112." Chemistry - A European Journal, volume 15, number 46, 2009, pp. 12770–12779. doi:10.1002/chem.200901472

Pyykkö, Pekka, and Michiko Atsumi. "Molecular Single-Bond Covalent Radii for Elements 1-118." Chemistry - A European Journal, volume 15, number 1, 2009, pp. 186–197. doi:10.1002/chem.200800987

Pyykkö, Pekka, Sebastian Riedel, and Michael Patzschke. "Triple-Bond Covalent Radii." Chemistry - A European Journal, volume 11, number 12, 2005, pp. 3511–3520. doi:10.1002/chem.200401299

Ringnes, Vivi. "Origin of the Names of Chemical Elements." Journal of Chemical Education, volume 66, number 9, 1989, pp. 731–738. doi:10.1021/ed066p731

Rohrer, Gregory S. Structure and Bonding in Crystalline Materials. Cambridge: Cambridge University Press, 2001.

Sansonetti, J. E., and W. C. Martin. "Handbook of Basic Atomic Spectroscopic Data." Journal Of Physical And Chemical Reference Data, volume 34, number 4, 2005, pp. 1559–2259. doi:10.1063/1.1800011

Scientific Group Thermodata Europe (SGTE). Pure Substances: Part 1—Elements and Compounds from AgBr to Ba3N2. Edited by I. Hurtado and D. Neuschütz. Berlin: Springer-Verlag, 1999. doi:10.1007/10652891_3

Seaborg, Glenn T., and Walter D. Loveland. The Elements Beyond Uranium. New York: John Wiley & Sons, Inc., 1990.

Shannon, R. D. "Revised Effective Ionic Radii and Systematic Studies of Interatomic Distances in Halides and Chalcogenides." Acta Crystallographica Section A, volume 32, number 5, 1976, pp. 751–767. doi:10.1107/S0567739476001551

Silbey, Robert J., Robert A. Alberty, and Moungi G. Bawendi. Physical Chemistry, 4th edition. Hoboken, NJ: John Wiley & Sons, Inc., 2005.

Singman, Charles N. "Atomic Volume and Allotropy of the Elements." Journal of Chemical Education, volume 61, number 2, 1984, pp. 137–142. doi:10.1021/ed061p137

Slater, J. C. "Atomic Radii in Crystals." The Journal of Chemical Physics, volume 41, number 10, 1964, pp. 3199–3204. doi:10.1063/1.1725697

Smith, Derek W. Inorganic Substances: A Prelude to the Study of Descriptive Inorganic Chemistry. Cambridge: Cambridge University Press, 1990.

Stewart, G. R. "Measurement of low-temperature specific heat." Review of Scientific Instruments, volume 54, number 1, 1983, pp. 1–11. doi:10.1063/1.1137207

Stewart, G. R. "Measurement of Low-Temperature Specific Heat." Review of Scientific Instruments, volume 54, number 1, 1983, pp. 1–11. doi:10.1063/1.1137207

Tari, A. The Specific Heat of Matter at Low Temperatures. London: Imperial College Press, 2003.

Vainshtein, Boris K., Vladimir M. Fridkin, and Vladimir L. Indenbom. Structure of Crystals, 2nd edition. Modern Crystallography 2. Edited by Boris K. Vainshtein, A. A. Chernov, and L. A. Shuvalov. Berlin: Springer-Verlag, 1995.

Waber, J. T., and Don T. Cromer. "Orbital Radii of Atoms and Ions." Journal of Chemical Physics, volume 42, number 12, 1965, pp. 4116–4123. doi:10.1063/1.1695904

Weeks, Mary Elvira, and Henry M. Leicester. Discovery of the Elements, 7th edition. Easton, PA: Journal of Chemical Education, 1968.

Yaws, Carl L. The Yaws Handbook of Physical Properties for Hydrocarbons and Chemicals. Houston, TX: Gulf Publishing Company, 2005.