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)	-100.42	8.40	kJ mol-1	JANAF
Hfg(0K)	-101.58	8.40	kJ mol-1	JANAF
Entropy (298.15K)	211.58		J K-1 mol-1	JANAF
Integrated Heat Capacity (0 to 298.15K)	8.72		kJ mol-1	JANAF
Heat Capacity (298.15K)	29.90		J K-1 mol-1	webbook

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	1242	NISTDiatomic

Detailed diatomic data

ωe	ωexe	ωeye	Be	αe	ZPE	reference
1241.544	5.97437	6.090213E-03	0.726752	5.03784E-03	619.3922	2007Iri:389

vibrational zero-point energy: 620.8 cm^-1
Calculated vibrational frequencies for SiO^- (silicon monoxide anion).

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

A	B	C	reference	comment
	0.72675	0.72675	NISTdiatomic

Calculated rotational constants for SiO^- (silicon monoxide anion).

Product of moments of inertia
23.19585	amu Å2		3.851821E-39	gm cm2

Geometric Data

Point Group C_∞v

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
rSiO	1.510	0.000	1	2			NISTdiatomic

Cartesians

Atom	x (Å)	y (Å)	z (Å)
Si1	0.0000	0.0000	0.0000
O2	0.0000	0.0000	1.5097

Atom - Atom Distances
Distances in Å

	Si1	O2
Si1		1.5097
O2	1.5097

Calculated geometries for SiO^- (silicon monoxide anion).

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

Bond Type	Count
O-Si	1

Connectivity

Atom 1	Atom 2
Si1	O2

Electronic energy levels (cm^-1)

Energy (cm-1)	Degeneracy	reference	description
0	1	1979HUB/HER	1Σ

Ionization Energies (eV)

Ionization Energy	I.E. unc.	vertical I.E.	v.I.E. unc.	Electron Affinity	E.A. unc.	reference
11.490	0.200					webbook

Dipole, Quadrupole and Polarizability
Electric dipole moment

Dipole (Debye)	Reference	comment
3.098	NISTdiatomic

Calculated electric dipole moments for SiO^- (silicon monoxide anion).
Electric quadrupole moment
Calculated electric quadrupole moments for SiO^- (silicon monoxide anion).

References
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squib	reference	DOI
1979HUB/HER	Huber, K.P.; Herzberg, G., Molecular Spectra and Molecular Structure. IV. Constants of Diatomic Molecules,, Van Nostrand Reinhold Co., 1979
2007Iri:389	KK Irikura "Experimental Vibrational Zero-Point Energies: Diatomic Molecules" J. Phys. Chem. Ref. Data 36(2), 389, 2007	10.1063/1.2436891
JANAF	Chase, M.W., Jr.; Davies, C.A.; Downey, J.R., Jr.; Frurip, D.J.; McDonald, R.A.; Syverud, A.N., JANAF Thermochemical Tables (Third Edition), J. Phys. Chem. Ref. Data,Suppl. 1, 1985, 14, 1.
NISTdiatomic	NIST Diatomic Spectral Database (www.physics.nist.gov/PhysRefData/MolSpec/Diatomic/index.html)
webbook	NIST Chemistry Webbook (http://webbook.nist.gov/chemistry)

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