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Hydrogen Quick Reference

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Notes

Symbol

H

Atomic Number

1

Atomic Weight

Rounded

1.008

for regular calculations

Standard

1.00784 to 1.00811

for precise calculations

Oxidation States

 1

more common

 0

less common

-1

more common with disagreement

Pauling Electronegativity

2.20

Electron Configuration

Orbital Occupancy

1s1

Orbital Filling Order

1s1

Term Symbol

2S1/2

see expanded configuration ...

Ionization Energies

I (1)

13.598433 eV

Electron Affinity

 0.75420375 ± 0.00000003 eV

6083.064145 ± 0.000030 cm-1

Density

gas

400.0 K, 1 atm

0.06139 g/L

parahydrogen

300.0 K

1 atm

0.08184 g/L

parahydrogen

1 bar

0.08077 g/L

parahydrogen

25 °C, 1 atm

0.0824 g/L 

280.0 K, 1 atm

0.08769 g/L

parahydrogen

273.15 K, 1 atm

0.08995 g/L

270.0 K, 1 atm

0.09093 g/L

parahydrogen

200.0 K, 1 atm

0.1228 g/L 

parahydrogen

liquid, 13.95 K

0.0776 g/ml

solid, 4 K

0.088 g/cm3

see all 58 densities ...

Molar Volume

gas, 273.15 K, 1 atm

22.4135 L/mol 

solid, 0 K, 0 atm

para-H2

23.207 cm3/mol

ortho-D2

19.95 cm3/mol 

T2

18.18 cm3/mol 

HD

21.25 cm3/mol 

HT

19.94 cm3/mol 

DT

18.96 cm3/mol 

Melting Point

146 GPa

 880 ± 50 K

106 GPa

1050 ± 60 K

melting curve maximum

1 atm

14.01 K

1 bar

13.95 K

Boiling Point

1 atm

20.388 K

Normal hydrogen consists of 75% orthohydrogen and 25% parahydrogen. This temperature is an ITS-90 second-quality, secondary reference point.

Thermal Conductivity

gas (normal hydrogen)

400 K, 1 atm

0.2212 W/(m K)

300 K, 1 atm

0.1815 W/(m K)

290 K, 1 atm

0.1767 W/(m K)

280 K, 1 atm

0.1717 W/(m K)

270 K, 1 atm

0.1665 W/(m K)

200 K, 1 atm

0.1280 W/(m K)

see all 56 conductivities ...

Pyykkö Covalent Radius

single bond

32 pm

Atomic Radius

37 pm

Enthalpy of Fusion

1 atm

0.12 kJ/mol

Enthalpy of Vaporization

1 atm

0.46 kJ/mol

Quantity

Hydrogen Atomic Structure

Notes

Ionization Energies

I (1)

13.598433 eV

Electron Affinity

 0.75420375 ± 0.00000003 eV

6083.064145 ± 0.000030 cm-1

Electron Binding Energies

(1s)

13.6 eV

Electron Configuration

Orbital Occupancy

1s1

Orbital Filling Order

1s1

Term Symbol

2S1/2

see expanded configuration ...

Screening Percentage

0.0%

Fluorescence Yields

ωK

0.00002

Quantity

Hydrogen Physical Properties

Notes

Density

gas

400.0 K, 1 atm

0.06139 g/L

parahydrogen

300.0 K

1 atm

0.08184 g/L

parahydrogen

1 bar

0.08077 g/L

parahydrogen

25 °C, 1 atm

0.0824 g/L 

280.0 K, 1 atm

0.08769 g/L

parahydrogen

273.15 K, 1 atm

0.08995 g/L

270.0 K, 1 atm

0.09093 g/L

parahydrogen

200.0 K, 1 atm

0.1228 g/L 

parahydrogen

liquid, 13.95 K

0.0776 g/ml

solid, 4 K

0.088 g/cm3

see all 58 densities ...

Molar Mass

Rounded

1.008 g/mol

for regular calculations

Standard

1.00784 g/mol to 1.00811 g/mol

for precise calculations

Molar Volume

gas, 273.15 K, 1 atm

22.4135 L/mol 

solid, 0 K, 0 atm

para-H2

23.207 cm3/mol

ortho-D2

19.95 cm3/mol 

T2

18.18 cm3/mol 

HD

21.25 cm3/mol 

HT

19.94 cm3/mol 

DT

18.96 cm3/mol 

Physical Form

colorless gas

Speed of Sound

gas

400.0 K, 1 atm

1518.0 m/s

parahydrogen

300.0 K, 1 atm

1310.0 m/s

parahydrogen

27 °C, 1 atm

1310 m/s  

280.0 K, 1 atm

1263.0 m/s

parahydrogen

270.0 K, 1 atm

1239.0 m/s

parahydrogen

200.0 K, 1 atm

1054.0 m/s

parahydrogen

see all 57 speeds of sound ...

Dielectric Constant

440 °F

1.23   

20 °C, 1 atm

1.00025

13.52 K

1.28   

deuterium, 68 °F

1.3    

Isothermal Bulk Modulus

4 K

0.2 GPa

Isothermal Compressibility

4 K

5 GPa-1

Gram Atomic Volume

13 cm3

Quantity

Hydrogen Atomic Interaction

Notes

Oxidation States

 1

more common

 0

less common

-1

more common with disagreement

Pauling Electronegativity

2.20

Mulliken-Jaffe Electronegativity

orbitals

2.25

Sanderson Electronegativity

2.592

Allred-Rochow Electronegativity

2.20

Configuration Energy

electron volt units

13.61 eV

Pauling units

 2.300  

Allen Electronegativity

2.300

Allred Electronegativity

oxidation state: 1

2.20

Ghosh-Gupta Electronegativity

7.1862 eV

Nagle Electronegativity

2.27

Pearson Absolute Electronegativity

7.18 eV

Smith Electronegativity

oxidation state: 1

2.1

oxidation state: -1

2.0

Chemical Hardness

6.43 eV

Quantity

Hydrogen Thermodynamics

Notes

Melting Point

146 GPa

 880 ± 50 K

106 GPa

1050 ± 60 K

melting curve maximum

1 atm

14.01 K

1 bar

13.95 K

Boiling Point

1 atm

20.388 K

Normal hydrogen consists of 75% orthohydrogen and 25% parahydrogen. This temperature is an ITS-90 second-quality, secondary reference point.

Thermal Conductivity

gas (normal hydrogen)

400 K, 1 atm

0.2212 W/(m K)

300 K, 1 atm

0.1815 W/(m K)

290 K, 1 atm

0.1767 W/(m K)

280 K, 1 atm

0.1717 W/(m K)

270 K, 1 atm

0.1665 W/(m K)

200 K, 1 atm

0.1280 W/(m K)

see all 56 conductivities ...

Triple Point

equilibrium

temperature

13.8033 K

Equilibrium hydrogen near this temperature consists of 0.21% orthohydrogen and 99.79% parahydrogen. This temperature is an ITS-90 fixed point.

pressure

7.030 kPa

normal

temperature

13.952 K

Normal hydrogen consists of 75% orthohydrogen and 25% parahydrogen. This temperature is an ITS-90 second-quality, secondary reference point.

pressure

7.200 kPa

deuterium

equilibrium

temperature

18.689 K

Equilibrium deuterium at the triple point consists of 98.5% orthohydrogen and 1.5% parahydrogen. This temperature is an ITS-90 first-quality, secondary reference point.

pressure

17.130 kPa

normal

temperature

18.724 K

Normal deuterium at the triple point consists of 66.7% orthohydrogen and 33.3% parahydrogen. This temperature is an ITS-90 first-quality, secondary reference point.

pressure

17.150 kPa

tritium

temperature

20.62 K

pressure

21.6 kPa

Critical Point

equilibrium

temperature

32.976 K

pressure

1.293 MPa

normal

temperature

33.19 K

pressure

1.315 MPa

deuterium

equilibrium

temperature

38.262 K

pressure

1.650 MPa

normal

temperature

38.34 K

pressure

1.665 MPa

tritium

temperature

40.44 K

estimate

pressure

1.850 MPa

Vapor Pressure

-252.8 °C

100 kPa

-258.6 °C

10 kPa

14 K

7.90 kPa

see all 22 pressures ...

Enthalpy of Fusion

1 atm

0.12 kJ/mol

Enthalpy of Vaporization

1 atm

0.46 kJ/mol

Isobaric Molar Heat Capacity

gas

400.0 K, 1 atm

29.33 J/(mol K) 

parahydrogen

300.0 K

1 atm

29.93 J/(mol K) 

parahydrogen

1 bar

29.93 J/(mol K) 

parahydrogen

298.15 K, 1 bar

28.836 J/(mol K)

280.0 K, 1 atm

30.23 J/(mol K) 

parahydrogen

270.0 K, 1 atm

30.43 J/(mol K) 

parahydrogen

see all 54 capacities ...

Isobaric Specific Heat Capacity

298.15 K, 1 bar

14.304 J/(g K)

Isochoric Molar Heat Capacity

gas

400.0 K, 1 bar

21.02 J/(mol K)

parahydrogen

300 K, 1 bar

21.61 J/(mol K)

parahydrogen

280.0 K, 1 bar

21.92 J/(mol K)

parahydrogen

270 K, 1 bar

22.11 J/(mol K)

parahydrogen

200 K, 1 bar

24.08 J/(mol K)

parahydrogen

see all 57 capacities ...

Debye Temperature

Low Temperature Limit ( 0 K )

122 K

Quantity

Hydrogen Identification

Notes

CAS Number

1333-74-0

DOT Number

1049

absorbed in metal hydride

9279

compressed

1049

in a metal hydride storage system

3468

in a metal hydride storage system contained in equipment

3468

in a metal hydride storage system packed with equipment

3468

refrigerated liquid (cryogenic liquid)

1966

ICSC Number

0001

RTECS Number

MW8900000

UN Number

1049

Quantity

Hydrogen Atomic Size

Notes

Atomic Radius

37 pm

Orbital Radius

52.9 pm

Pyykkö Covalent Radius

single bond

32 pm

Cordero Covalent Radius

31 pm

Shannon-Prewitt Crystal Radius

ion charge: +1

coordination number: 1

-24 pm

coordination number: 2

 -4 pm

Shannon-Prewitt Effective Ionic Radius

ion charge: +1

coordination number: 1

-38 pm

coordination number: 2

-18 pm

Pauling Empirical Crystal Radius

ion charge: -1

208 pm

Pauling Univalent Radius

ion charge: -1

208 pm

Bondi Van Der Waals Radius

120 pm

Pauling Van Der Waals Radius

1.2×102 pm

Slater Atomic-Ionic Radius

25 pm

Quantity

Hydrogen Crystal Structure

Notes

Allotropes

allotrope

α-hydrogen

symbol

αH

allotrope

β-hydrogen

symbol

βH

Quantity

Hydrogen History

Notes

Discovery

date of discovery

1766

discoverer

Henry Cavendish

birth

October 10, 1731

death

February 24, 1810

location of discovery

London, England

Origin of Element Name

origin

hydros gen

origin description

property—Greek for water producing

Origin of Element Symbol

symbol: H

origin

hydrogen

origin description

element name

Quantity

Hydrogen Abundances

Notes

Earth's Crust

1.40×103 ppm

Earth's Mantle

0.012%

primitive mantle

Earth's Core

600 ppm

Bulk Earth

260 ppm

Earth's Atmosphere

0.55 ppm

H2

Ocean Water

1.078×105 ppm

River Water

1.119×105 ppm

U.S. Coal

5.2%

Human Body

7 kg

based on a 70 kg "reference man"

Human Bone

52×103 ppm

Human Hair

29×103 ppm

Human Kidney

93×103 ppm

Human Liver

93×103 ppm

Human Muscle

93×103 ppm

Human Nail

29×103 ppm

Bacteria

74×103 ppm

Ferns

55×103 ppm

Fungi

55×103 ppm

Universe

1.00000

relative to hydrogen = 1.00000

Solar System

2.79×1010

number of atoms for every 106 atoms of silicon

Sun

12.00

base 10 log of the number of atoms for every 1012 atoms of hydrogen

Halley's Comet

2025 ± 385 atoms

number of atoms for every 100 atoms of magnesium

Quantity

Hydrogen Nomenclature

Notes

Element Names in Other Languages

French

hydrogène

German

Wasserstoff

Italian

idrogeno

Spanish

hidrógeno

Portuguese

hidrogênio

Anions or Anionic Substituent Groups

hydride (general)

H-, hydride (natural or unspecified isotopic composition)

1H-, protide

2H- = D-, deuteride

3H- = T-, tritide

Cations or Cationic Substituent Groups

hydrogen (general)

H+, hydrogen(1+), hydron (natural or unspecified isotopic composition)

1H+, protium(1+), proton

2H+ = D+, deuterium(1+), deuteron

3H+ = T+, tritium(1+), triton

Ligands

hydrido

protido

deuterido

tritido

Heteroatomic Anion

hydrogenate

'y' Term—Chains and Rings Nomenclature

hydrony

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

Albright, Thomas A., and Jeremy K. Burdett. Problems in Molecular Orbital Theory. New York: Oxford University Press, 1992.

Allen, Leland C. "Electronegativity Is the Average One-Electron Energy of the Valence-Shell Electrons in Ground-State Free Atoms." Journal of the American Chemical Society, volume 111, number 25, 1989, pp. 9003–9014. doi:10.1021/ja00207a003

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

Anders, Edward, and Nicolas Grevesse. "Abundances of the Elements: Meteoritic and Solar." Geochimica et Cosmochimica Acta, volume 53, number 1, 1989, pp. 197–214. doi:10.1016/0016-7037(89)90286-X

Andersen, T., H. K. Haugen, and H. Hotop. "Binding Energies in Atomic Negative Ions: III." Journal of Physical and Chemical Reference Data, volume 28, number 6, 1999, pp. 1511–1533.

Batsanov, S. S. "Van der Waals Radii of Elements." Inorganic Materials, volume 37, number 9, 2001, pp. 871–885. See abstract

Bearden, J. A., and A. F. Burr. "Reevaluation of X-Ray Atomic Energy Levels." Reviews of Modern Physics, volume 39, number 1, 1967, pp. 125–142. doi:10.1103/RevModPhys.39.125

Bedford, R. E., G. Bonnier, H. Maas, and F. Pavese. "Recommended Values of Temperature on the International Temperature Scale of 1990 for a Selected Set of Secondary Reference Points." Metrologia, volume 33, number 2, 1996, pp. 133–154. doi:10.1088/0026-1394/33/2/3

Bondi, A. "Van der Waals Volumes and Radii." The Journal of Physical Chemistry, volume 68, number 3, 1964, pp. 441–451. doi:10.1021/j100785a001

Bowen, H. J. M. Environmental Chemistry of the Elements. London: Academic Press, Inc., 1979.

Bratsch, Steven G. "Revised Mulliken Electronegativities: I. Calculation and Conversion to Pauling Units." Journal of Chemical Education, volume 65, number 1, 1988, pp. 34–41. doi:10.1021/ed065p34

Cohen, E. Richard, David R. Lide, and George L. Trigg, editors. AlP Physics Desk Reference, 3rd edition. New York: Springer-Verlag New York, Inc., 2003.

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.

Croswell, Ken. The Alchemy of the Heavens. New York: Anchor Books, 1995.

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

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.

Eremets, M. I., and I. A. Trojan. "Evidence of Maximum in the Melting Curve of Hydrogen at Megabar Pressures." JETP Letters, volume 89, number 4, 2009, pp. 174–179. doi:10.1134/S0021364009040031

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.

Galasso, Francis S. Structure and Properties of Inorganic Solids. Oxford: Pergamon Press, 1970.

Ghosh, Dulal C., and Kartick Gupta. "A New Scale Of Electronegativity Of 54 Elements Of Periodic Table Based On Polarizability Of Atoms." Journal of Theoretical and Computational Chemistry, volume 5, number 4, 2006, pp. 895–911. doi:10.1142/S0219633606002726

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

Griffiths, David J. Introduction to Electrodynamics, 2nd edition. Upper Saddle River, NJ: Prentice-Hall Inc., 1989.

Gwyn Williams. Electron Binding Energies. http://www.jlab.org/~gwyn/ebindene.html. Accessed on April 30, 2010.

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.

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.

International Labour Organization (ILO). International Chemical Safety Card for Hydrogen. http://www.ilo.org/legacy/english/protection/safework/cis/products/icsc/dtasht/_icsc00/icsc0001.htm. Accessed on May 5, 2010.

International Labour Organization (ILO). International Chemical Safety Card for Hydrogen. http://www.ilo.org/legacy/english/protection/safework/cis/products/icsc/dtasht/_icsc00/icsc0001.htm. Accessed on May 4, 2010.

Jessberger, Elmar K., Alexander Christoforidis, and Jochen Kissel. "Aspects of the Major Element Composition of Halley's Dust." Nature, volume 332, number 21, 1988, pp. 691–695. doi:10.1038/332691a0

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

Liboff, Richard L. Introductory Quantum Mechanics, 3rd edition. Reading, MA: Addison Wesley Longman, Inc., 1998.

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

Lykke, K. R., K. K. Murray, and W. C. Lineberger. "Threshold Photodetachment of H-." Physical Review A, volume 43, number 11, 1991, pp. 6104–6107. doi:10.1103/PhysRevA.43.6104

Magomedov, M. N. "The Surface Energy of Cryocrystals." Technical Physics Letters, volume 31, number 12, 2005, pp. 1039–1042. doi:10.1134/1.2150892

Mann, Joseph B., Terry L. Meek, and Leland C. Allen. "Configuration Energies of the Main Group Elements." Journal of the American Chemical Society, volume 122, number 12, 2000, pp. 2780–2783. doi:10.1021/ja992866e

Manuel, O., editor. Origin of Elements in the Solar System: Implications of Post-1957 Observations. New York: Kluwer Academic Publishers, 2000.

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

McDonough, W. F. "Compositional Model for the Earth's Core." pp. 547–568 in The Mantle and Core. Edited by Richard W. Carlson. Oxford: Elsevier Ltd., 2005.

Mechtly, Eugene A. "Properties of Materials." pp. 4–1 to 4–33 in Reference Data For Engineers: Radio, Electronics, Computer, and Communications. By Mac E. Van Valkenburg, edited by Wendy M. Middleton. Woburn, MA: Butterworth-Heinemann, 2002. doi:10.1016/B978-075067291-7/50006-6

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

National Aeronautics and Space Administration (NASA). Earth Fact Sheet. http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html. Accessed on September 18, 2011.

National Institute for Occupational Safety and Health (NIOSH). International Chemical Safety Card for Hydrogen. http://www.cdc.gov/niosh/ipcsneng/neng0001.html. Accessed on May 4, 2010.

National Institute for Occupational Safety and Health (NIOSH). International Chemical Safety Card for Hydrogen. http://www.cdc.gov/niosh/ipcsneng/neng0001.html. Accessed on May 5, 2010.

National Institute for Occupational Safety and Health (NIOSH). The Registry of Toxic Effects of Chemical Substances for Hydrogen. http://www.cdc.gov/niosh-rtecs/mw87cda0.html. Accessed on May 5, 2010.

Nicholas, J. V., and D. R. White. "Temperature." pp. 8–41 in Measurement of the Thermodynamic Properties of Single Phases. Edited by A. R. H. Goodwin, W. A. Wakeham, and K. N. Marsh. Amsterdam: Elsevier Science, 2003.

Orem, W. H., and R. B. Finkelman. "Coal Formation and Geochemistry." pp. 191–222 in Sediments, Diagenesis, and Sedimentary Rocks. Edited by Fred T. Mackenzie. Oxford: Elsevier Ltd., 2005.

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

Palme, H., and H. Beer. "Meteorites and the Composition of the Solar Photosphere." pp. 204–206 in Landolt–Börnstein—Group VI: Astronomy and Astrophysics. Edited by H. H. Voigt. New York: Springer–Verlag, 1993. doi:10.1007/10057790_59

Palme, H., and Hugh St. C. O'Neill. "Cosmochemical Estimates of Mantle Composition." pp. 1–38 in The Mantle and Core. Edited by Richard W. Carlson. Oxford: Elsevier Ltd., 2005.

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

Pearson, Ralph G. "Absolute Electronegativity and Hardness: Application to Inorganic Chemistry." Inorganic Chemistry, volume 27, number 4, 1988, pp 734–740. doi:10.1021/ic00277a030

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

Preston-Thomas, H. "The International Temperature Scale of 1990 (ITS-90)." Metrologia, volume 27, number 1, 1990, pp. 3–10. doi:10.1088/0026-1394/27/1/002

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

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.

Sanderson, R. T. Simple Inorganic Substances. Malabar, FL: Robert E. Krieger Publishing Co., Inc., 1989.

Sanderson, R. T. "Principles of Electronegativity: Part I. General Nature." Journal of Chemical Education, volume 65, number 2, 1988, pp. 112–118. doi:10.1021/ed065p112

Sanderson, R. T. Polar Covalence. New York: Academic Press, Inc., 1983.

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

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.

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. "Electronegativity in Two Dimensions: Reassessment and Resolution of the Pearson-Pauling Paradox." Journal of Chemical Education, volume 67, number 11, 1990, pp. 911–914. doi:10.1021/ed067p911

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

Souers, P. Clark. Hydrogen Properties for Fusion Energy. Berkeley, CA: University of California Press, 1986.

Speight, James G. Perry's Standard Tables and Formulas for Chemical Engineers. New York: The McGraw-Hill Companies, Inc., 2003.

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.

Tonkov, E. Yu, and E. G. Ponyatovsky. Phase Transformations of Elements Under High Pressure. Advances in Metallic Alloys 4. Edited by J. N. Fridlyander and D. G. Eskin. Boca Raton, Florida: CRC Press LLC, 2005.

U. S. Department of Transportation (DOT), Transport Canada (TC), Secretariat of Transport and Communications of Mexico (SCT), and Centro de Información Química para Emergencias (CIQUIME). 2008 Emergency Response Guidebook.

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.

Waldron, Kimberley A., Erin M. Fehringer, Amy E. Streeb, Jennifer E. Trosky, and Joshua J. Pearson. "Screening Percentages Based on Slater Effective Nuclear Charge as a Versatile Tool for Teaching Periodic Trends." Journal of Chemical Education, volume 78, number 5, 2001, pp. 635–639. doi:10.1021/ed078p635

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

Wieser, Michael E., and Tyler B. Coplen. "Atomic weights of the elements 2009 (IUPAC Technical Report)." Pure and Applied Chemistry, volume 83, number 2, 2011, pp. 359–396. doi:10.1351/PAC-REP-10-09-14

Yaws, Carl L. "Liquid Density of the Elements." Chemical Engineering, volume 114, number 12, 2007, pp. 44–46.

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

Younglove, B. A. "Thermophysical Properties of Fluids. I. Argon, Ethylene, Parahydrogen, Nitrogen, Nitrogen Trifluoride, and Oxygen." Journal of Physical and Chemical Reference Data, volume 11, supplement 1, 1982, pp. 1–1 to 1–353.

Zefirov, Yu. V. "Comparative Analysis of Systems of van der Waals Radii." Crystallography Reports, volume 42, number 1, 1997, pp. 111–116.