Some Properties of Silicon Difluoride

Timms, Peter L.; Kent, R. A.; Ehlert, Thomas C.; Margrave, John L.

doi:10.1038/207187b0

Cited by 24 publications

(12 citation statements)

References 5 publications

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“…All reactions were carried out in a greaseless vacuum system and difluorosilylene was generated as a mixture of approximate 1:1 SiFz/SiF4 by passing SiF4 through a column of silicon lumps heated at 1150 "C. 16 All reagents were commercial products used without further purification. Liquid reagents were degassed before used.…”

Section: (D) Insertion Of Sif 2 Into P-cl Bondmentioning

confidence: 99%

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Reactions of Difluorosilylene with Amines, Phosphines and Halomethanes The First Evidence of the Insertion of Difluorosilylene into Tetrafluorosilane

Chang

Liu

Lee

1999

J Chinese Chemical Soc

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The reactions of SiFjSiF 4 with amines, phosphines and various halomethanes were studied. The resultsshow that in the presence of strong Lewis base (Et 3N, HNEt 2 , PR 3, PR 2Cl), SiF 2 inserts initially into SiF 4 W form Si 2F 6, which was followed by subsequent reactions leading to products containing SiF 3 groups. This is the first report of the insertion of SiF 2 into Sif 4 , When the reactants were a weaker base (such as RPCI2, CX 3Br, X::=:F, CI), insertion of SiF 2 into P-Cl and C-Br bonds became predominant.

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Section: (D) Insertion Of Sif 2 Into P-cl Bondmentioning

confidence: 99%

“…The liquid collected at -30 "C containing compounds 13,14,15,16,17,18,20,21,22 and various chlorofluorosilanes (SiCJ., SiChF, SiChF2, SiClF,) was obtained. A solid product (EtP)s 12 was also obtained.…”

Section: Reaction Between Sifysif4 and Ethyldichlorophosphinementioning

confidence: 99%

Reactions of Difluorosilylene with Amines, Phosphines and Halomethanes The First Evidence of the Insertion of Difluorosilylene into Tetrafluorosilane

Chang

Liu

Lee

1999

J Chinese Chemical Soc

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“…The above direct detection characterizations could not confirm the stable existence of the (SiF 2 ) x polymer, so researchers needed to prove its existence by indirect methods. First, a SiF n ( n = 1–4)-mixed air flow was prepared under high temperature, and then, unsaturated hydrocarbons (propylene, butadiene, benzene, ethylene fluoride, etc. − ), BF 3 , H 2 O, , H 2 S, GeH 4 , and PF 3 were introduced. Finally, the mixed system was rapidly frozen at low temperature, and the system was heated for the detection and characterization to confirm the presence of the polymer.…”

Section: Introductionmentioning

confidence: 99%

Study on Pyrolytic Mechanisms of n-Perfluorosilanes Si_nF_2n+2 (2 ≤ n < 6) and Perfluorocyclosilanes Si_nF_2n (3 ≤ n ≤ 6)

et al. 2021

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In this paper, the pyrolytic mechanisms of n-perfluorosilanes Si n F 2n+2 (2 ≤ n < 6) and perfluorocyclosilanes Si n F 2n (3 ≤ n ≤ 6) are studied in terms of kinetics and thermodynamics by theoretical calculation, and the pyrolytic reaction paths of Si n F 2n+2 (2 ≤ n < 6) and Si n F 2n (3 ≤ n ≤ 6) are obtained, which can be used to guide the experimental preparation research studies and separation operations of Si n F 2n+2 (2 ≤ n < 6), Si n F 2n (3 ≤ n ≤ 6), and their intermediate substances. The results of the kinetic analysis show that the pyrolytic mechanisms of Si n F 2n+2 (2 ≤ n < 6) are as follows: first, the silicon−silicon bond breaking induces the generation of free radicals; then, in the chain transfer, the related free radicals participate in F-abstraction transfer with the molecules; and finally, the free radicals form the molecules, and the chain terminates. The F-abstraction transfer is the easiest process to initiate in the low-order silicon−fluorine substance during the chain transfer while releasing SiF 2 at the same time, whereas the generation of double free radicals is the most difficult process. The pyrolytic mechanisms of Si n F 2n (3 ≤ n ≤ 6) are as follows: first, the α−Si−Si bond breaking induces the generation of double free radicals; then, the α−Si−Si or β−Si−Si bond breaks continually in the chain transfer; and finally, the double free radicals form the molecules, and the chain terminates. SiF 2 is most easily formed by breaking during the chain transfer. In the pyrolytic processes of Si n F 2n+2 (2 ≤ n < 6) and Si n F 2n (3 ≤ n ≤ 6), the chain initiation of silicon−silicon bond breaking requires the highest bond breaking energy, which is the control step of the pyrolytic reaction. The results of the thermodynamic analysis show that the pyrolytic reactions of Si n F 2n+2 (2 ≤ n < 6) and Si n F 2n (3 ≤ n ≤ 6) are endothermic. When Si n F 2n+2 (2 ≤ n < 6) undergoes a pyrolytic reaction and the temperature is higher, the main pyrolytic products are SiF 4 and SiF 2 . When 600 K < T < 1200 K, the main pyrolytic products of Si 4 F 10 are Si 3 F 8 and SiF 2 , and when 900 K < T < 1400 K, Si 5 F 12 can also convert to Si 3 F 8 and SiF 2 . The main pyrolytic products of Si n F 2n (3 ≤ n ≤ 6) are SiF 2 . When the temperature is higher, the pyrolytic order of Si n F 2n (3 ≤ n ≤ 6) is as follows: Si 3 F 6 (ring) < Si 4 F 8 (ring) < Si 5 F 10 (ring) < Si 6 F 12 (ring). However, if the temperature is in the range of 1000 K < T < 1200 K, the pyrolytic order is the opposite.

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“…In fact, both neutral and charged species are involved in various processes such as chemical vapour deposition and glow discharge deposition [2]. Among the silicon compounds, silicon dihalides, SiX 2 (X ¼ F, Cl, Br, I), are particularly important in synthetic chemistry and they have been the subject of various studies [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Silicon difluoride is one of the major product in plasma etching of silicon containing films in the manufacture of microelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

“…Silicon difluoride is one of the major product in plasma etching of silicon containing films in the manufacture of microelectronic devices. Silicon difluoride is the dihalide that has been most extensively studied experimentally [3][4][5][6][7]10,14,18] and theoretically [1,2,8,9,[11][12][13]17]. Silicon dichloride is an active intermediate in lowpressure discharges of chlorosilanes and this is mainly responsible for the increasing interest in the study of the compound [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Molecular structure, atomization energy, ionization energy, electron affinity and vibrational spectrum of SiX₂(X = F, Cl, Br, I) by theoretical methods

Kinoo

Ramasami

2008

Main Group Chemistry

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The molecular structure, atomization energy, ionization energy, electron affinity and vibrational spectra of silicon dihalides, SiX 2 (X ¼ F, Cl, Br, I), have been obtained using theoretical methods in the gas phase. The neutral dihalides, their cations and anions have been studied in C 2v symmetry. The neutral species have been considered in both the 1 A 1 singlet and 3 B 1 triplet states whereas the cations (SiX 2 þ ) and anions (SiX 2 7) have been considered in the 2 A 1 and 2 B 1 states, respectively. The methods used are Møller-Plesset perturbation theory (MP2), density functional theory (DFT), Gaussian-2 (G2) and complete basis set methods (CBS-4 and CBS-Q). The functional used for the DFT method is B3LYP. The basis sets used are 6-311þþG(d,p) for all atoms except that 6-311G(d,p) has been used for iodine atom only. The silicon dihalides, their cations and anions have been fully optimized using MP2 and DFT methods. Single point energy computations (G2, CBS-4M and CBS-Q) have been performed except for silicon diiodide. The results obtained are in good agreement with literature although they are method dependent.

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Some Properties of Silicon Difluoride

Cited by 24 publications

References 5 publications

Reactions of Difluorosilylene with Amines, Phosphines and Halomethanes The First Evidence of the Insertion of Difluorosilylene into Tetrafluorosilane

Reactions of Difluorosilylene with Amines, Phosphines and Halomethanes The First Evidence of the Insertion of Difluorosilylene into Tetrafluorosilane

Study on Pyrolytic Mechanisms of n-Perfluorosilanes Si_nF_2n+2 (2 ≤ n < 6) and Perfluorocyclosilanes Si_nF_2n (3 ≤ n ≤ 6)

Molecular structure, atomization energy, ionization energy, electron affinity and vibrational spectrum of SiX₂(X = F, Cl, Br, I) by theoretical methods

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Some Properties of Silicon Difluoride

Cited by 24 publications

References 5 publications

Reactions of Difluorosilylene with Amines, Phosphines and Halomethanes The First Evidence of the Insertion of Difluorosilylene into Tetrafluorosilane

Reactions of Difluorosilylene with Amines, Phosphines and Halomethanes The First Evidence of the Insertion of Difluorosilylene into Tetrafluorosilane

Study on Pyrolytic Mechanisms of n-Perfluorosilanes SinF2n+2 (2 ≤ n < 6) and Perfluorocyclosilanes SinF2n (3 ≤ n ≤ 6)

Molecular structure, atomization energy, ionization energy, electron affinity and vibrational spectrum of SiX2(X = F, Cl, Br, I) by theoretical methods

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Product

Resources

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Study on Pyrolytic Mechanisms of n-Perfluorosilanes Si_nF_2n+2 (2 ≤ n < 6) and Perfluorocyclosilanes Si_nF_2n (3 ≤ n ≤ 6)

Molecular structure, atomization energy, ionization energy, electron affinity and vibrational spectrum of SiX₂(X = F, Cl, Br, I) by theoretical methods