Enthalpy of formation (Hfg), Entropy, Integrated heat capacity (0 K to 298.15 K) (HH), Heat Capacity (Cp)

Property	Value	Uncertainty	units	Reference	Comment
Hfg(298.15K)	221.00	15.00	kJ mol-1	1973Kor/Gin:135
Hfg(0K)		15.00	kJ mol-1	1973Kor/Gin:135

Information can also be found for this species in the NIST Chemistry Webbook

Vibrational levels (cm^-1)

Mode Number	Symmetry	Frequency (cm-1)	Frequency Reference	Intensity (km mol-1)	Int. unc.	Intensity Reference	Comment
1	Σ	430	webbook

vibrational zero-point energy: 214.8 cm^-1
Calculated vibrational frequencies for As₂ (Arsenic diatomic).

Rotational Constants (cm^-1)
See section I.F.4 to change rotational constant units

A	B	C	reference	comment
	0.10179		webbook

Calculated rotational constants for As₂ (Arsenic diatomic).

Product of moments of inertia
165.6118	amu Å2		2.750092E-38	gm cm2

Geometric Data

Point Group D_∞h

Internal coordinates
distances (r) in Å, angles (a) in degrees, dihedrals (d) in degrees

Description	Value	unc.	Connectivity				Reference	Comment
			Atom 1	Atom 2	Atom 3	Atom 4
rAsAs	2.103		1	2			webbook

Cartesians

Atom	x (Å)	y (Å)	z (Å)
As1	0.0000	0.0000	0.0000
As2	0.0000	0.0000	2.1026

Atom - Atom Distances
Distances in Å

	As1	As2
As1		2.1026
As2	2.1026

Calculated geometries for As₂ (Arsenic diatomic).

Bond descriptions
Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond

Bond Type	Count
As-As	1

Connectivity

Atom 1	Atom 2
As1	As2

Electronic energy levels (cm^-1)

Energy (cm-1)	Degeneracy	reference	description

Ionization Energies (eV)

Ionization Energy	I.E. unc.	vertical I.E.	v.I.E. unc.	Electron Affinity	E.A. unc.	reference
10.000	0.200			0.739	0.008	webbook

Dipole, Quadrupole and Polarizability
Electric dipole moment
For a molecule with D_∞h symmetry there is no dipole.
Electric quadrupole moment
Calculated electric quadrupole moments for As₂ (Arsenic diatomic).

References
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squib	reference	DOI
1973Kor/Gin:135	J Kordis, KA Gingerich "Atomization Energy and Standard Heat of Formation of Gaseous Diatomic Arsenic" J. Chemical and Engineering Data 18(2), 135, 1973	10.1021/je60057a023
webbook	NIST Chemistry Webbook (http://webbook.nist.gov/chemistry)

Got a better number? Please email us at cccbdb@nist.gov