National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
XOlder CCCBDB versions
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers

NIST policy on privacy, security, and accessibility.

Please rate our products
© 2013 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

The National Institute of Standards and Technology (NIST) is an agency of the U.S. Department of Commerce.

Please send questions, comments, corrections, additions and suggestions to

return to home page

II.A.1. (XV.A.)

Listing of experimental data for As4 (Arsenic tetramer)

InChI=1S/As4/c1-2-3(1)4(1)2/t1-,2+,3-,4+ UYVQXFOBKTWZCW-GNSDDBTRSA-N [As]12[As]3[As]1[As]23
State Conformation
1A1 Td
Enthalpy of formation (Hfg), Entropy, Integrated heat capacity (0 K to 298.15 K) (HH), Heat Capacity (Cp)
Property Value Uncertainty units Reference Comment
Information can also be found for this species in the NIST Chemistry Webbook
Vibrational levels (cm-1) vibrations
Mode Number Symmetry Frequency (cm-1) Frequency Reference Intensity (km mol-1) Int. unc. Intensity Reference Comment

Calculated vibrational frequencies for As4 (Arsenic tetramer).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment

Calculated rotational constants for As4 (Arsenic tetramer).

Product of moments of inertia moments of inertia
amu3Å6   0gm3 cm6
Geometric Data
picture of Arsenic tetramer

Point Group Td

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 2.435   1 2 1976Hellwege(II/7) ED


Atom x (Å) y (Å) z (Å)
As1 0.8609 0.8609 0.8609
As2 0.8609 -0.8609 -0.8609
As3 -0.8609 0.8609 -0.8609
As4 -0.8609 -0.8609 0.8609

Atom - Atom Distances bond lengths
Distances in Å

  As1 As2 As3 As4
As1   2.43502.43502.4350
As2 2.4350   2.43502.4350
As3 2.43502.4350   2.4350
As4 2.43502.43502.4350  

Calculated geometries for As4 (Arsenic tetramer).

Experimental Bond Angles (degrees) from cartesians bond angles

atom1 atom2 atom3 angle         atom1 atom2 atom3 angle
As1 As2 As3 60.000 As1 As2 As4 60.000
As1 As3 As2 60.000 As1 As3 As4 60.000
As1 As4 As2 60.000 As1 As4 As3 60.000
As2 As1 As3 60.000 As2 As1 As4 60.000
As2 As3 As4 60.000 As2 As4 As3 60.000
As3 As1 As4 60.000 As3 As2 As4 60.000

Bond descriptions

Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond
Bond Type Count
As-As 6


Atom 1 Atom 2
As1 As2
As1 As3
As1 As4
As2 As3
As2 As4
As3 As4
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. reference
9.300 0.300     webbook
Dipole, Quadrupole and Polarizability
Electric dipole moment dipole
For a molecule with Td symmetry there is no dipole.
Electric quadrupole moment quadrupole
For a molecule with Td symmetry there is no quadrupole.

By selecting the following links, you may be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to
squib reference DOI
1976Hellwege(II/7) Hellwege, KH and AM Hellwege (ed.). Landolt-Bornstein: Group II: Atomic and Molecular Physics Volume 7: Structure Data of Free Polyatomic Molecules. Springer-Verlag. Berlin. 1976.  
webbook NIST Chemistry Webbook (  

Got a better number? Please email us at