Difluorosilylene

Formula: F₂Si
Molecular weight: 66.0823
IUPAC Standard InChI: InChI=1S/F2Si/c1-3-2
IUPAC Standard InChIKey: MGNHOGAVECORPT-UHFFFAOYSA-N
CAS Registry Number: 13966-66-0
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript.
Permanent link for this species. Use this link for bookmarking this species for future reference.
Information on this page:
Data at other public NIST sites:
Options:
- Switch to calorie-based units

Gas phase thermochemistry data

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, References, Notes

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-587.85	kJ/mol	Review	Chase, 1998	Data last reviewed in December, 1977
Quantity	Value	Units	Method	Reference	Comment
S°_{gas,1 bar}	256.58	J/mol*K	Review	Chase, 1998	Data last reviewed in December, 1977

Gas Phase Heat Capacity (Shomate Equation)

C_p° = A + B*t + C*t² + D*t³ + E/t²
H° − H°_298.15= A*t + B*t²/2 + C*t³/3 + D*t⁴/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t²/2 + D*t³/3 − E/(2*t²) + G
C_p = heat capacity (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.

View plot Requires a JavaScript / HTML 5 canvas capable browser.

View table.

Temperature (K)	298. to 1000.	1000. to 6000.
A	31.80677	57.64632
B	67.03354	0.580982
C	-65.39215	-0.239494
D	22.79765	0.034826
E	-0.185259	-1.985761
F	-600.4040	-610.8473
G	276.7444	317.3074
H	-587.8520	-587.8520
Reference	Chase, 1998	Chase, 1998
Comment	Data last reviewed in December, 1977	Data last reviewed in December, 1977

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Vibrational and/or electronic energy levels, References, Notes

Data compiled as indicated in comments:
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
B - John E. Bartmess

View reactions leading to F₂Si⁺ (ion structure unspecified)

Electron affinity determinations

EA (eV)	Method	Reference	Comment
0.10 ± 0.10	LPES	Kawamata, Neigishi, et al., 1996	Vertical Detachment Energy: 0.68±0.02 eV; B

Ionization energy determinations

IE (eV)	Method	Reference	Comment
10.78 ± 0.05	PE	Westwood, 1974	LLK
11.3 ± 0.1	EI	McDonald, Williams, et al., 1968	RDSH
11.08	PE	Fehlner and Turner, 1974	Vertical value; LLK

Vibrational and/or electronic energy levels

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, References, Notes

Data compiled by: Marilyn E. Jacox

State: B

Energy (cm^-1)	Med.	Transition	λ_min (nm)	λ_max (nm)	References


T_o = 62280	gas	B-X	158	165	Gole, Hauge, et al., 1972
					Dagata, Squire, et al., 1987
					Horwitz, Dulcey, et al., 1988
					Johnson, Hudgens, et al., 1996

Vib. sym.	No.	Approximate type of mode	cm^-1		Med.	Method	References


a₁	1	Sym. stretch	790	T	gas	AB MPI	Gole, Hauge, et al., 1972 Johnson, Hudgens, et al., 1996
	2	Bend	320	T	gas	AB	Gole, Hauge, et al., 1972

State: A

Energy (cm^-1)		Med.	Transition	λ_min (nm)	λ_max (nm)	References


T_o = 44113.9		gas	A-X	213	276	Johns, Chantry, et al., 1958
						Rao and Venkateswarlu, 1961
						Khanna, Besenbruch, et al., 1967
						Dixon and Halle, 1970
						Matsumi, Toyoda, et al., 1986
						Vanhaelemeersch, Van Hoeymissen, et al., 1991
						Biehl, Boyle, et al., 1997
T_o = 43964	T	Ne	A-X	216	225	Milligan and Jacox, 1968

Vib. sym.	No.	Approximate type of mode	cm^-1		Med.	Method	References


a₁	2	Bend	250.1 ± 0.3		gas	AB LF	Khanna, Besenbruch, et al., 1967 Dixon and Halle, 1970 Vanhaelemeersch, Van Hoeymissen, et al., 1991 Karolczak, Judge, et al., 1995
	2	Bend	253	T	Ne	AB	Milligan and Jacox, 1968

State: a

Energy (cm^-1)	Med.	Transition	λ_min (nm)	λ_max (nm)	References


T_o = 26319.478 ± 0.006	gas	a-X	364	420	Rao, 1970
					Horwitz, Dulcey, et al., 1988
					Karolczak, Judge, et al., 1995
					Johnson, Hudgens, et al., 1996
					Biehl, Boyle, et al., 1997
					Harper, Clouthier, et al., 1998

Vib. sym.	No.	Approximate type of mode	cm^-1	Med.	Method	References


a₁	2	Bend	278.2	gas	EM LF	Rao, 1970 Horwitz, Dulcey, et al., 1988 Karolczak, Judge, et al., 1995

State: X

Vib. sym.	No.	Approximate type of mode	cm^-1		Med.	Method	References


a₁	1	Sym. stretch	855.01		gas	IR LF	Khanna, Hauge, et al., 1967 Caldow, Deeley, et al., 1981 Vanhaelemeersch, Van Hoeymissen, et al., 1991
	1	Sym. stretch	851	s	Ne	IR	Hastie, Hauge, et al., 1969
	1	Sym. stretch	843	s	Ar	IR	Milligan and Jacox, 1968 Hastie, Hauge, et al., 1969
	2	Bend	345		gas	MW UV	Rao and Curl, 1966 Khanna, Besenbruch, et al., 1967
	2	Bend	345		gas	LF MPI	Vanhaelemeersch, Van Hoeymissen, et al., 1991 Johnson, Hudgens, et al., 1996
	2	Bend	343		Ar	IR	Milligan and Jacox, 1968
b₂	3	Asym. stretch	870.40		gas	IR	Khanna, Hauge, et al., 1967 Caldow, Deeley, et al., 1981
	3	Asym. stretch	864.6	s	Ne	IR	Hastie, Hauge, et al., 1969
	3	Asym. stretch	855	vs	Ar	IR	Milligan and Jacox, 1968 Hastie, Hauge, et al., 1969

Additional references: Jacox, 1994, page 100; Jacox, 1998, page 197; Jacox, 2003, page 140; Rao, Curl, et al., 1965; Fehlner and Turner, 1974; Bizzocchi and Degli Esposti, 2006

Notes

Strong

Very strong

Tentative assignment or approximate value

Energy separation between the v = 0 levels of the excited and electronic ground states.

References

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Vibrational and/or electronic energy levels, Notes

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Kawamata, Neigishi, et al., 1996
Kawamata, H.; Neigishi, Y.; Kishi, R.; Iwata, S.; Nakajima, A.; Kaya, K., Photoelectron Spectroscopy of Silicon-Fluorine Binary Cluster Anions (SinFm-), J. Chem. Phys., 1996, 105, 13, 5369, https://doi.org/10.1063/1.472377 . [all data]

Westwood, 1974
Westwood, N.P.C., The photoelectron spectrum of silicon difluoride, Chem. Phys. Lett., 1974, 25, 558. [all data]

McDonald, Williams, et al., 1968
McDonald, J.D.; Williams, C.H.; Thompson, J.C.; Margrave, J.L., Appearance potentials, ionization potentials and heats of formation for perfluorosilanes and perfluoroborosilanes, Advan. Chem. Ser., 1968, 72, 261. [all data]

Fehlner and Turner, 1974
Fehlner, T.P.; Turner, D.W., The photoelectron spectrum of SiF₂, Inorg. Chem., 1974, 13, 754. [all data]

Gole, Hauge, et al., 1972
Gole, J.L.; Hauge, R.H.; Margrave, J.L.; Hastie, J.W., The vaccum ultraviolet spectra of SiF2 and GeF2, J. Mol. Spectrosc., 1972, 43, 3, 441, https://doi.org/10.1016/0022-2852(72)90055-0 . [all data]

Dagata, Squire, et al., 1987
Dagata, J.A.; Squire, D.W.; Dulcey, C.S.; Hsu, D.S.Y.; Lin, M.C., MPI/MS detection of SiF and SiF2 radicals produced from the reaction of F2 and NF3 with silicon, Chem. Phys. Lett., 1987, 134, 2, 151, https://doi.org/10.1016/0009-2614(87)87112-9 . [all data]

Horwitz, Dulcey, et al., 1988
Horwitz, J.S.; Dulcey, C.S.; Lin, M.C., REMPI/MS detection of SiF2 radicals by (3+1) and (1+3) photoionization, Chem. Phys. Lett., 1988, 150, 1-2, 165, https://doi.org/10.1016/0009-2614(88)80415-9 . [all data]

Johnson, Hudgens, et al., 1996
Johnson, R.D., III; Hudgens, J.W.; Ashfold, M.N.R., Excited electronic states of the SiF2 radical studied by resonance enhanced multiphoton ionisation spectroscopy and by ab initio methods, Chem. Phys. Lett., 1996, 261, 4-5, 474, https://doi.org/10.1016/0009-2614(96)00990-6 . [all data]

Johns, Chantry, et al., 1958
Johns, J.W.C.; Chantry, G.W.; Barrow, R.F., The ultra-violet spectrum of silicon difluoride, Trans. Faraday Soc., 1958, 54, 1589, https://doi.org/10.1039/tf9585401589 . [all data]

Rao and Venkateswarlu, 1961
Rao, D.R.; Venkateswarlu, P., Emission spectrum of SiF2, J. Mol. Spectrosc., 1961, 7, 1-6, 287, https://doi.org/10.1016/0022-2852(61)90362-9 . [all data]

Khanna, Besenbruch, et al., 1967
Khanna, V.M.; Besenbruch, G.; Margrave, J.L., Ultraviolet Absorption Spectrum of SiF2, J. Chem. Phys., 1967, 46, 6, 2310, https://doi.org/10.1063/1.1841037 . [all data]

Dixon and Halle, 1970
Dixon, R.N.; Halle, M., Rotational analysis of absorption bands in the 2266 Å system of SiF2, J. Mol. Spectrosc., 1970, 36, 2, 192, https://doi.org/10.1016/0022-2852(70)90104-9 . [all data]

Matsumi, Toyoda, et al., 1986
Matsumi, Y.; Toyoda, S.; Hayashi, T.; Miyamura, M.; Yoshikawa, H.; Komiya, S., Laser-induced fluorescence study of silicon etching process: Detection of SiF2 and CF2 radicals, J. Appl. Phys., 1986, 60, 12, 4102, https://doi.org/10.1063/1.337489 . [all data]

Vanhaelemeersch, Van Hoeymissen, et al., 1991
Vanhaelemeersch, S.; Van Hoeymissen, J.; Vermeylen, D.; Peeters, J., SiF2 as a primary desorption product of Si etching by F atoms: Interpretation of laser-induced fluorescence spectra; rate constant of the gas phase SiF2+F reaction, J. Appl. Phys., 1991, 70, 7, 3892, https://doi.org/10.1063/1.349197 . [all data]

Biehl, Boyle, et al., 1997
Biehl, H.; Boyle, K.J.; Seccombe, D.P.; Smith, D.M.; Tuckett, R.P.; Yoxall, K.R.; Baumgartel, H.; Jochims, H.W., Vacuum-UV fluorescence spectroscopy of SiF[sub 4] in the range 10--30 eV, J. Chem. Phys., 1997, 107, 3, 720, https://doi.org/10.1063/1.474437 . [all data]

Milligan and Jacox, 1968
Milligan, D.E.; Jacox, M.E., Matrix-Isolation Study of the Vacuum-Ultraviolet Photolysis of Difluorosilane. The Infrared and Ultraviolet Spectra of the Free Radical SiF2, J. Chem. Phys., 1968, 49, 10, 4269, https://doi.org/10.1063/1.1669870 . [all data]

Karolczak, Judge, et al., 1995
Karolczak, J.; Judge, R.H.; Clouthier, D.J., Experimental Determination of the Structure of SiF2 in Its Excited Triplet State, J. Am. Chem. Soc., 1995, 117, 37, 9523, https://doi.org/10.1021/ja00142a020 . [all data]

Rao, 1970
Rao, D.R., New electronic emission from SiF2, J. Mol. Spectrosc., 1970, 34, 2, 284, https://doi.org/10.1016/0022-2852(70)90093-7 . [all data]

Harper, Clouthier, et al., 1998
Harper, W.W.; Clouthier, D.J.; Judge, R.H., Rotational Analysis of the 210and 220Bands of the ã3B1←X1A1System of Jet-Cooled Silicon Difluoride, J. Mol. Spectrosc., 1998, 189, 1, 46, https://doi.org/10.1006/jmsp.1998.7527 . [all data]

Khanna, Hauge, et al., 1967
Khanna, V.M.; Hauge, R.; Curl, R.F., Jr.; Margrave, J.L., J. Chem. Phys., 1967, 47, 5031. [all data]

Caldow, Deeley, et al., 1981
Caldow, G.L.; Deeley, C.M.; Turner, P.H.; Mills, I.M., The infrared spectrum of silicon difluoride, Chem. Phys. Lett., 1981, 82, 3, 434, https://doi.org/10.1016/0009-2614(81)85414-0 . [all data]

Hastie, Hauge, et al., 1969
Hastie, J.W.; Hauge, R.H.; Margrave, J.L., Infrared spectra of silicon difluroide in neon and argon matrixes, J. Am. Chem. Soc., 1969, 91, 10, 2536, https://doi.org/10.1021/ja01038a024 . [all data]

Rao and Curl, 1966
Rao, V.M.; Curl, R.F., Jr., Microwave Spectrum and Force Constants of SiF2: Centrifugal Distortion, J. Chem. Phys., 1966, 45, 6, 2032, https://doi.org/10.1063/1.1727887 . [all data]

Jacox, 1994
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules, American Chemical Society, Washington, DC, 1994, 464. [all data]

Jacox, 1998
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules: supplement A, J. Phys. Chem. Ref. Data, 1998, 27, 2, 115-393, https://doi.org/10.1063/1.556017 . [all data]

Jacox, 2003
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules: supplement B, J. Phys. Chem. Ref. Data, 2003, 32, 1, 1-441, https://doi.org/10.1063/1.1497629 . [all data]

Rao, Curl, et al., 1965
Rao, V.M.; Curl, R.F., Jr.; Timms, P.L.; Margrave, J.L., Microwave Spectrum of SiF2, J. Chem. Phys., 1965, 43, 7, 2557, https://doi.org/10.1063/1.1697165 . [all data]

Bizzocchi and Degli Esposti, 2006
Bizzocchi, L.; Degli Esposti, C., Millimeter and submillimeter-wave spectroscopy of silicon difluoride, J. Mol. Spectrosc., 2006, 235, 1, 117, https://doi.org/10.1016/j.jms.2005.10.011 . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Vibrational and/or electronic energy levels, References

Symbols used in this document:

EA Electron affinity

S°_{gas,1 bar} Entropy of gas at standard conditions (1 bar)

Δ_fH°_gas Enthalpy of formation of gas at standard conditions
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
Customer support for NIST Standard Reference Data products.

EA	Electron affinity
S°_{gas,1 bar}	Entropy of gas at standard conditions (1 bar)
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions