Template:Infobox helium

[[Category:Template:Pagetype with short description]]

Helium, ₂He

File:Helium discharge tube.jpg
Helium
Pronunciation	/ˈhiːliəm/ ​(Template:Respell)
Appearance	colorless gas, exhibiting a gray, cloudy glow (or reddish-orange if an especially high voltage is used) when placed in an electric field
Standard atomic weight Ar, std(He)	Template:Val
Helium in the periodic table
Template:Periodic table (32 columns, micro) – ↑ He ↓ Ne hydrogen ← helium → lithium
Atomic number (Z)	2
Group	group 18 (noble gases)
Period	period 1
Block	s-block
Electron configuration	1s2
Electrons per shell	2
Physical properties
Phase at STP	gas
Melting point	0.95 K ​(−272.20 °C, ​−457.96 °F) (at 2.5 MPa)
Boiling point	4.222 K ​(−268.928 °C, ​−452.070 °F)
Density (at STP)	0.1786 g/L
when liquid (at m.p.)	0.145 g/cm3
when liquid (at b.p.)	0.125 g/cm3
Triple point	2.177 K, ​5.043 kPa
Critical point	5.1953 K, 0.22746 MPa
Heat of fusion	0.0138 kJ/mol
Heat of vaporization	0.0829 kJ/mol
Molar heat capacity	20.78 J/(mol·K)
Vapor pressure (defined by ITS-90) P (Pa) 1 10 100 1 k 10 k 100 k at T (K)     1.23 1.67 2.48 4.21
Atomic properties
Oxidation states	0
Electronegativity	Pauling scale: no data
Ionization energies	1st: 2372.3 kJ/mol 2nd: 5250.5 kJ/mol
Covalent radius	28 pm
Van der Waals radius	140 pm
Color lines in a spectral range Spectral lines of helium
Other properties
Natural occurrence	primordial
Crystal structure	​hexagonal close-packed (hcp) Hexagonal close-packed crystal structure for helium
Speed of sound	972 m/s
Thermal conductivity	0.1513 W/(m·K)
Magnetic ordering	diamagnetic
Magnetic susceptibility	−1.88·10−6 cm3/mol (298 K)
CAS Number	7440-59-7
History
Naming	after Helios, Greek god of the Sun
Discovery	Pierre Janssen, Norman Lockyer (1868)
First isolation	William Ramsay, Per Teodor Cleve, Abraham Langlet (1895)
Main isotopes of helium
[[Isotope|IsoTemplate:Shytope]] [[Natural abundance|AbunTemplate:Shydance]] Half-life (t1/2) Decay mode [[Decay product|ProTemplate:Shyduct]] 3He 0.0002% stable 4He 99.9998% stable

[[Category:Infobox templates|Template:Remove first word]]

He Template:Wikidata data m.p. cat
	in	calc from C	diff	report	ref
C	−272.20	—	—
K	0.95	0.950	0
F	−457.96	−457.960	0		Template:Subpage other
max precision	2
WD	Template:Wikidata				Template:Wikidata
input	C: −272.20, K: 0.95, F: −457.96
comment	(at 2.5 MPa)

He Template:Wikidata data b.p. cat
	in	calc from C	diff	report	ref
C	−268.928	—	—
K	4.222	4.222	0
F	−452.070	−452.070	0		Template:Subpage other
max precision	3
WD	Template:Wikidata				Template:Wikidata
input	C: −268.928, K: 4.222, F: −452.070
comment

PTHelium

H ← i'box H	iso 2He () infobox () isobox	→ Li i'box Li
Commons  Wikidata:Q560  Wiktionary Indexes in PT: § below · Page

Data sets read by {{Infobox element}}
Name and identifiers
Top image (caption, alt)
Pronunciation
Category (enwiki)
Standard atomic weight
most stable isotope
Natural occurrence
Phase at STP
Oxidation states
Spectral lines image
Electron configuration (cmt, ref)
Term symbol * (cmt, ref)
Wikidata *
* Not used in {{Infobox element}} (2019-02-03) See also {{Infobox element/symbol-to--navbox}}

References

These references will appear in the article, but this list appears only on this page.

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• <ref name = "CIAAW2013" /> for the source Atomic weights of the elements 2013 (from subtemplates used by {{Infobox element}})

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