Insulation Strength and Decomposition Characteristics of a C₆F₁₂O and N₂ Gas Mixture

Abstract

This paper explores the decomposition characteristics of a new type of environmentally friendly insulating gas C₆F₁₂O and N₂ mixed gas under AC voltage. The breakdown behavior of 3% C₆F₁₂O and N₂ mixed gas in quasi-uniform field was investigated through a breakdown experiment. The self-recovery of the mixed gas was analyzed by 100 breakdown experiments. The decomposition products of C₆F₁₂O and N₂ under breakdown voltage were determined by gas chromatography–mass spectrometer (GC-MS). Finally, the decomposition process of the products was calculated by density functional theory, and the ionization energy, affinity, and molecular orbital gap of the decomposition products were also calculated. The properties of the decomposition products were analyzed from the aspects of insulation and environmental protection. The experimental results show that the 3% C₆F₁₂O and N₂ mixed gas did not show a downward trend over 100 breakdown tests under a 0.10 MPa breakdown voltage. The decomposition products after breakdown were CF₄, C₂F₆, C₃F₆, C₃F₈, C₄F₁₀, and C₅F₁₂. The ionization energies of several decomposition products are more than 10 eV. The Global Warming Potential (GWP) values of the main products are lower than SF₆. C₂F₆, C₃F₈, and C₄F₁₀ have better insulation properties.

1. Introduction

Conventional gases (N₂, CO₂, and air) are relatively stable in terms of physical and chemical properties with a low preparation cost. They are widely used as insulating gases in medium- and low-pressure gas insulation equipment such as gas-insulated switchgear (c-GIS) [1]. However, applying reasonable measures to increase the insulation performance of conventional gases, such as increasing the pressure of the gas chamber, increasing the size of the equipment, and using a combination of gas solids, is necessary given their low insulation properties.

Toshiba researchers studied the thermal breaking performance of CO₂ gas by measuring the characteristics of arc current and arc time constant, and they reported the prototype of CO₂ tank circuit breaker with 72 kV rating and breaking capacity of 31.5 kA. However, its volume and weight is approximately 1.5 to 2 times that of the SF₆ circuit breaker at a pressure of 0.7 MPa [2]. Compressed air and N₂ have also been used for 24 kV, 72 kV, and other medium voltage switchgear insulations. To obtain the equivalent of SF₆ gas dielectric strength, the pressure of N₂ must be increased to 3–4 times of SF₆ given that the insulation strength of pure N₂ is low [3]. Korea Hyundai Heavy Industries [4], Toshiba, and other researchers have used air-solid composite insulation technology to enhance the role of its insulation [5]. The results show that the appropriate insulation materials on the high electric field electrode surface coating can effectively improve its electrical strength. Therefore, the current use of conventional gas in the switch equipment must optimize the structure of the device and increase the pressure and the size of the equipment to increase the production cost of the equipment.

The use of SF₆ gas mixtures are considered given that SF₆ gas in the dielectric strength relative to other insulating medium has evident advantages. The addition of SF₆ can enhance the insulation performance and maintain the pressure to keep the equipment structure compact [6]. However, the ”Kyoto Protocol,” which was formulated in 1997, emphasized SF₆ as one of the six greenhouse gases with GWP of 23,900 times that of CO₂; moreover, the use of SF₆ should be gradually reduced and an environmentally friendly insulation gas to replace the SF₆ should be selected. Therefore, the recent research and exploration of a new type of environmentally friendly gas has been considered [7]. SF₆ is mainly composed of strong negative gases and mixed gases (CF₃I, c-C₄F₈, C₃F₈, and C₂F₆) [8,9,10]. Among them, the GWP values of c-C₄F₈, C₃F₈, and C₂F₆ are less than that of SF₆, but greater than that of CO₂; thus, the greenhouse effect cannot be ignored. CF₃I has acceptable insulation performance and a GWP value of 0. However, the gas in the discharge has a solid iodine precipitation, affecting insulation performance.

C₆F₁₂O is non-combustible and non-toxic and currently limited for use in fire extinguishing agent [11], magnesium treatment, and two-phase immersion cooling system covered gas [12]. C₆F₁₂O molecule is an ozone depletion potential (ODP) gas with a GWP value close to 1 and dielectric strength of approximately 1.7 times that of pure SF₆ gas [13]. The structure of C₆F₁₂O is mainly the combination of the characteristic double and single bonds of ketone carbonyl and its prominent dielectric strength can be attributed to the strong electron absorption capacity of high fluorine content in molecular structure. The mixing ratio in the mixed gas is relatively low (less than 10%) because gas liquefaction temperature is extremely high (liquefaction temperature of 49 °C at 0.1 MPa). The discharge of insulating gas under the insulation defect leads to decomposition, and the insulating properties of the decomposition products are important indexes to evaluate insulating gas. The current decomposition of C₆F₁₂O is limited to the interaction of C₆F₁₂O with oxygen or air in the extinguishing state [14], and the decomposition properties of C₆F₁₂O gas under discharge have not been reported. Therefore, detecting the decomposition products of the insulating gas to ensure its safety, analyzing the physical and chemical properties, and insulating properties of the decomposition products, and evaluating its influence on the gas insulation performance and the environment are necessary.

The present study initially explores the C₆F₁₂O mixed N₂ decomposition characteristics under frequency AC voltage breakdown. Firstly, the decomposition products of C₆F₁₂O and N₂ mixed gas after 0.10 MPa were investigated. Secondly, the change in the surface elements of the electrode was detected using photoelectron spectroscopy. Thirdly, gas decomposition products of the mixed gas are detected by GC-MS. Fourth, binding test results were used to calculate the decomposition process of the products based on density functional theory (DFT), and the ionization energy, affinity, and molecular orbital gap of the decomposition products were calculated. Finally, the properties of the decomposition products and the influence on the insulation properties of the mixed gas were analyzed.

2. Experiment

The experimental wiring diagram of the power frequency voltage experiment platform is shown in Figure 1. The sphere electrodes are placed in the insulating gas chamber, and the electrode material is copper with a diameter of 50 mm and an electrode spacing of 5 mm.

T₁:

Induction voltage regulator with an input voltage of 380 V and an output voltage of 0–400 V;

T₂:

Non-corona test transformer can provide the power frequency test voltage of 100 kV;

R:

Protection resistance of R = 10 kΩ, which can protect the transformer from being damaged in breakdown;

C_V:

Capacitive divider, in which the test voltage with high amplitude can be converted into the lower value which can be measured directly by the voltmeter;

V:

Voltmeter measures the voltage through the capacitive divider.

C₆F₁₂O gas is liquid at room temperature because its liquefaction temperature is 49 °C. The saturated vapor pressure of the gas satisfies the Antoine equation, and the saturated vapor pressure of C₆F₁₂O is 40 kPa at 25 °C [13]. The Antoine equation is used to obtain the relation between saturated vapor pressure and the liquefaction temperature of C₆F₁₂O:

lgp = −3719.7385/T + 18.180

(1)

where T is the liquefaction temperature of gas, and p is the saturated vapor pressure of C₆F₁₂O.

According to Dalton’s law, ideally, the partial pressure of a gas in the gas mixture is equal to the pressure produced at the same temperature when it occupies the entire container alone, and the total pressure of gas mixture is equal to the sum of the gas partial pressure.

P_T = ∑P_i

(2)

where P_T is the total pressure of gas, and P_i is the partial pressure of each component. The two-component mixed gas is computed as follows:

P_T = P_C6 + P_N2 = k P_T + (1 − k) P_T

(3)

where k is the mixing ratio of C₆F₁₂O in the mixed gas. The liquefaction temperature of N₂ is −196 °C [15]. The liquefaction temperature of mixed gas only depends on C₆F₁₂O because the liquefaction temperature of C₆F₁₂O is 49 °C, which is much higher than that of N₂. The minimum operating temperature is −15 °C in the cold condition based on the operating temperature of the medium- and low-voltage equipment of −5 °C to 40 °C, and the main unit of the medium voltage equipment such as GIS must be at −25 °C [16]. To ensure that the mixture gas at less than −15 °C at 0.10 MPa is not liquefied, the mixing ratio of C₆F₁₂O should be less than 5%. We selected 3% C₆F₁₂O mixed N₂ to carry out the breakdown experiment, and the liquefaction temperature of mixed gas is −26 °C.

The breakdown voltage is measured under quasi uniform electric field at 0.10 MPa. The measured breakdown voltage is given as the root mean square (RMS) value. The experimental results show that the breakdown voltage of the 3% C₆F₁₂O mixed N₂ is approximately 1.9 times that of pure N₂ (the breakdown voltage of pure N₂ is approximately 7.6 kV). Thus, a small amount of C₆F₁₂O greatly improves the breakdown performance of N₂. The breakdown voltage has a certain discreteness given the 100 times breakdowns of 3% C₆F₁₂O/N₂ gas mixture. However, with the increase in the number of discharge, the breakdown voltage does not decrease, as shown in Figure 2.

At the end of the experiment, the surface elements of the sphere electrode are tested using Thermo Fisher’s ESCALAB 250Xi photoelectron spectroscopy. The gas chromatographic mass spectrometer (GC-MS) equipped with a special capillary column (CP-Sil5CB) is used to separately and qualitatively analyze the decomposition of the characteristic components. A total of 99.999% of the high purity He is used as the GC-MS carrier. The working conditions are as follows: the inlet temperature is 220 °C, the injection volume is 1 mL, the split ratio is 10, the ion source temperature is 200 °C, and the chromatographic mass interface temperature is 220 °C. The mode of ionization is the electron impact ionization (EI).

The sphere electrode surface of the three kinds of elements (C, O, and F) before and after breakdown is scanned using photoelectron spectroscopy. The results are shown in Figure 3. The abscissa is the energy value of the binding energy, whereas the ordinate is the number of photoelectrons per second. After the breakdown, the distribution of the three kinds of elements on the surface of the electrode evidently changed. The C atom increases, and the increase in the F atom is not evident. Before the experiment, the percentage of C, O, and F atoms on the electrode surface is 70.12%, 28.64%, and 1.24%, respectively, and the percentage of atoms on the surface of the electrode after the breakdown is 78.09%, 20.33%, and 1.58%, respectively. The content of C atoms increased by nearly 8%; thus, a small amount of C atoms from the gas are deposited on the surface of the electrode.

The gas in the gas chamber is tested by GC-MS. The detected results of the decomposition products are shown in Figure 4. The purity of C₆F₁₂O gas is 99.5%. The two kinds of chemical impurities are C₂HF₆P and C₆F₁₂, which are detected using a GC-MS spectrum library. The results, before and after the breakdown, are shown in Figure 4. According to standard gas and the corresponding GC-MS spectra similarity detection report (see Figure 5), the main decomposition products of compounds can be produced by the fluorocarbon compounds such as CF₄, C₂F₆, C₃F₈, C₃F₆, C₄F₁₀, and C₅F₁₂. The characteristic peaks of C₃F₆ and C₄F₁₀ overlap. The acquisition time of GC-MS is set to 4 min, and the retention time of N₂ is approximately 3 min; thus, N₂ does not form part of the results in Figure 4. The breakdown voltage of the C₆F₁₂O gas decomposition product is mainly fluorocarbon. Although the gas contains N₂, compounds containing N atoms are undetected. The molecular structure of C₆F₁₂O indicates that the formation of the products is mainly due to the formation of free radicals by the breaking of C–C bonds, and the free radicals are bonded to form the corresponding compounds.

3. Decomposition Process Calculation

The experimental detection of the C₆F₁₂O reaction with N₂ shows that the main products are CF₄, C₂F₆, C₃F₈, C₃F₆, C₄F₁₀, and C₅F₁₂, and these products also have certain insulation performance. The decomposition process is calculated using density functional theory (DFT), and the insulating property of several kinds of decomposition products is analyzed by calculating the ionization energy of the molecules, affinity energies, and molecular orbital gaps. The calculation is carried out by Dmol3 in the material studio (MS) computing software. The calculation method of the generalized gradient approximation (GGA) is selected and is based on the optimization of the local density approximation (LDA) functional; thus, GGA has higher accuracy than LDA. The GGA method and the Perdew, Burke, and Enzerhof (PBE) function are used to deal with the electron exchange interaction [17]. The function fitting d and p orbital polarization are used in the atomic orbital calculations through the p polarization dual numerical basis set (Double Numerical Set Plus Polarization Functions, DNP). The energy convergence precision, atomic migration, and energy gradient are set to 1.0 × 10⁻⁵ , 0.005, and 0.002 Ha, respectively, and the convergence precision of charge density is 1.0 × 10⁻⁶ Ha [18]. The Direct Inversion of Iterative Subspace (DIIS), which is used to improve the convergence rate of self-consistent field charge density, can be used to improve efficiency.

3.1. Formation of Decomposition Products

First, the molecular structure of C₆F₁₂O and several decomposition products are optimized to obtain the lowest stable state of molecular energy. To conveniently express the bond lengths and angles of each molecule, the structure of each molecule and the labeling of C atoms are presented in Figure 5. The optimized bond lengths and angles are shown in

Table 1. Bond lengths and angles.

Gas	Bond Length			Bond Angle
Species	Type	Value(Å)	Reference	Type	Value (°)	Reference
C6F12O	F–C1	1.402	-	F–C1–F	108.511	-
	C1–C2	1.566	-	F–C2–F	108.021	-
	F–C2	1.409	-	C1–C2–C3	115.584	-
	C2–C3	1.566	-	C2–C3=O	117.907	-
	C3=O	1.277	-	C2–C3–C4	124.115	-
	C3–C4	1.594	-	C3–C4–C5	113.574	-
	C4–F	1.439	-	F–C4–C6	104.340	-
	C4–C5, C4–C6	1.565	-	F–C5–F	108.519	-
	C5–F, C6–F	1.401	-			-
C5F12	F–C1	1.348	-	F–C1–F	108.719	-
	C1–C2	1.571	-	F–C1–C2	110.792	-
	C2–C3	1.579	-	F–C2–F	109.044	-
	F–C2	1.361	-	F–C2–C3	107.132	-
	F–C3	1.376	-	F–C3–C4	106.775	-
	C3–C4, C3–C5	1.583	-	C1–C2–C3	118.835	-
	C4–F, C5–F	1.348	-	C2–C3–C4	114.570	-
			-	C4–C3–C5	110.239	-
			-	F–C4–F	107.675	-
C4F10	F–C1, F–C4 F–C2, F–C3 C1–C2, C3–C4 C2–C3	1.349 1.360 1.568 1.564	-	F–C1–F F–C2–F, C1–C2–C3 C2–C3–C4 C1–C2–F	108.692 109.103 115.210 115.185 107.392	-
C3F8	C1–C2, C2–C3	1.563	1.54 [19]	F–C1–C2	108.783	109.1 [19]
	F–C1, F–C3	1.348	1.33 [19]	F–C2–F	108.892	108.6 [19]
	F–C2	1.359	1.34 [19]	F–C2–C3	109.292	109.5 [19]
				F–C3–C4	107.964	108.0 [19]
				C1–C2–C3	115.580	115.2 [19]
C3F6	C1–C2	1.497	1.498 [20]	C2–C3–C4	108.200	108.40 [20]
	C2=C3	1.341	1.329 [20]	C4–C3–C5	110.645	-
	F–C1	1.362	1.341 [20]	F–C4–F	113.505	-
	F–C2	1.350	1.337 [20]	F–C2=C3	118.849	-
	F–C3	1.324	1.329 [20]	F–C3–F	112.210	112.04 [20]
C2F6	C–C	1.591	1.56 ± 0.03 [21]	F–C–F	108.648	-
	C–F	1.347	1.32 ± 0.01 [21]	F–C–C	110.282	109.5 ± 1.5 [21]
CF4	C–F	1.341	1.3166 [22] 1.330 ± 0.005 [23]	F–C–F	109.471	-

. The results of the references are listed in the table. By contrast, the results of C₃F₈, C₃F₆, C₂F₆, and CF₄ are compared with the references, and the validity and accuracy of the model are verified.

The structure of the C₆F O is shown in Figure 6, and (1)–(4) indicates the position of bond breaking of C–C bond in the molecule.

Calculated by DFT, the four broken bond process and energy changes are as follows:

(1)

C₆F₁₂O → CF₃• + C₅F₉O• ΔH = 86.7857 kcal/mol

(2)

C₆F₁₂O → C₂F₅• + C₄F₇O• ΔH = 85.6439 kcal/mol

(3)

C₆F₁₂O → C₃F₅O• + C₃F₇• ΔH = 83.4267 kcal/mol

(4)

C₆F₁₂O → C₅F₉O• + CF₃• ΔH = 81.0649 kcal/mol

By calculating the energy of four C–C bonds, the absorbed energy in the four processes is found to be similar, that is, when the external energy is sufficiently large, the probability of the existence of several free radicals is similar. The free radicals, such as CF₃•, C₂F₅• and C₃F₇•, can produce F atoms by bond breaking reaction and form relatively stable fluorocarbon compounds, such as CF₄, C₂F₆, C₃F₈, C₃F₆, C₄F₁₀, and C₅F₁₂, between the radical combination process, as shown in Figure 7. CF₃• can be derived from the C₁–C₂ breaking and the C₄–C₅ or the C₄–C₆ breaking (shown in Figure 5).

CF₃ can continue to form CF₂ by breaking C–F, and the calculation in this paper is consistent with the literature [19] (the result in the literature is 84.92 kcal/mol). CF₂ can continue to eliminate F and eventually form a C atom; thus, a significant increase in C elements on the surface of the electrode is observed. The process must absorb the energy of 234.768 kcal/mol.

The numbers ①–⑩ in Figure 7 indicate the reactions and the related reactions is shown in

Table 2. Energy and barrier of decomposition product.

No.	Reaction	Energy of Reactants (Ha)	Energy of Products (Ha)	Temperature Correction Value (298 K) (kcal/mol)	Energy (kcal/mol)	Barrier (kcal/mol)
①	CF3• → F• + CF2:	−337.4509077	−337.3130314	−3.109	83.409	-
②	CF2: → 2F• + C	−237.5749908	−237.2185790	11.116	234.768	-
③	CF3• + CF3• → C2F6	−674.777429	−674.9387560	−0.238	−101.472	-
④	CF3• + F• → CF4	−437.0751517	−437.2801428	6.345	−122.289	-
⑤	C2F5• + F• → C2F6	−674.7368246	−674.9387560	6.444	−120.270	-
⑥	C2F5• + C2F5• → C4F10	−1150.1183793	−1150.2726764	3.302	−93.521	-
⑦	C2F5• + CF3• → C3F8	−912.4463898	−912.6071230	8.819	−92.043	-
⑧	C3F7• + F• → C3F8	−912.4310489	−912.6071230	6.755	−103.733	-
⑨	C3F7• → C3F6 + F•	−812.7456917	−812.6434617	−3.015	61.135	54.296
⑩	C2F5• + C3F7• → C5F12	−1387.8040065	−1387.9376407	3.565	−80.292	-

. C₂F₆ can be formed in two means, and the bond of the two free radicals, CF₃ or C₂F₅ and F, can also be formed. The formation of C₂F₆ has two paths, as shown in the reaction ③ and ⑤. The formation of C₃F₈ also has two paths, as shown in the reaction ⑦ and ⑧ in Figure 7. The formation of C₃F₆ requires C₃F₇• to eliminate F, and requires the C–C single bond to form the C=C double bond. Table 2 presents the main forming process of fluorocarbon, and the barrier energy changes, and the generation process. The energy calculation includes the zero-point vibrational energy (ZPVE) correction value and enthalpy correction.

Table 2 shows the C–C and C–F bond breaking of C₆F₁₂O to form the free radicals CF₃, C₂F₅, and C₃F₇, and the F atoms, whereas the free combination reaction to form stable fluorocarbon. In addition to the production process of C₃F₆, the other decomposition products generated include an exothermic reaction. The change in energy is the difference between the energy of the reactants. The calculation is carried out in 0 K; thus, the temperature correction is introduced at a normal temperature (298 K). The formation process of C₃F₆ not only includes the breaking of chemical bonds, but also the formation of chemical bonds. With the transition state search (TS search) activation energy calculation of the process, the energy of 61.135 kcal/mol must be absorbed to generate C₃F₆, and the reaction requires endothermic 54.296 kcal/mol to break the C–F bonds in C₃F₇. The formation processes of CF₄, C₂F₆, C₃F₈, C₄F₁₀, and C₅F₁₂ include simple bonding processes, compared with C₃F₆.

3.2. Basic Properties of C₆F₁₂O and Decomposition Products

To analyze the basic properties of C₆F₁₂O and the decomposition products of the molecule, DFT is used to calculate the adiabatic ionization energy of molecules E_ion, the adiabatic affinity energy E_aff, and the electron orbit distribution. The ionization and affinity energies are calculated by the following:

E_ion = E_x+ − E_x

(4)

E_aff = E_x − E_x-

(5)

where X is a molecule, and X- is a negative ion. X+ is a positive ion. E_ion represents the energy required for the loss of electrons and the ability of the gas molecule to bind electrons. E_aff is the energy released by the molecules adsorbed on the molecule and the ability of the molecule to adsorb electrons.

The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are generally referred to as frontier orbitals. The most active electrons in the electron chemical reaction in the frontline are the core of the chemical reaction. The molecular orbital energy gap E_O is used to describe the molecular activity.

E_O = E_LUMO − E_HOMO

(6)

where E_HOMO is the energy of the highest occupied molecular orbital, and E_LUMO is the energy of the lowest unoccupied molecular orbital. E_O indicates that the electrons in the molecule must be involved in the chemical reaction, which is required to overcome the orbital energy, and in the ability to participate in the chemical reaction. More stable molecules can bind electrons to relatively low levels of energy, and electrons are not easily ionized away from the orbital.

Several decomposition products are calculated using this method, and the comparative results are shown in

Table 3. Parameter comparison of C₆F₁₂O decomposition products.

Gas	Eion (eV)	Eaff (eV)	EO (eV)	Insulation Strength Relative to SF6 [25,26,27]	Boiling Point (°C) [27,28]	GWP (100 Years) [27,29]	Lifetime (Years) [27,30,31]
SF6	15.153	0.438	8.999	1	−63	23900	3200
C6F12O	11.408	0.817	6.120	2.70	49	~1	5 days
CF4	15.965	−1.253	12.590	0.39	−186.8	6300	50,000
C2F6	14.796	−1.208	11.570	0.78–0.79	−78	9200	10,000
C3F8	14.208	−0.673	10.330	0.96–0.97	−37	7000	2600
C3F6	11.759	1.755	5.129	-	−28	-	<10
C4F10	11.674	−1.841	7.973	1.25, 1.31	−2	7000	2600
C5F12	14.657	−0.906	7.680	-	28	7280	>2000

. The vertical affinity energy of SF₆ is 0.438 eV, which is consistent with the measured value (0.32 ± 0.15 eV) in the literature [24]. Table 3 shows that the ionization energy of the formation is relatively high; thus, the gas molecules have a strong ability to bind and to not easily lose electrons. The process of adsorption electrons of CF₄, C₂F₆, C₃F₈, C₄F₁₀, and C₅F₁₂ need absorb energy, whereas the adsorption electrons of C₃F₆ need release energy, and these energy values are relatively small. From the view of a molecular orbital gap, the difference between various molecules is large. The comprehensive evaluation reveals that the decomposition products after the breakdown of C₆F₁₂O with larger ionization energy have a certain degree of electronic adsorption capacity.

Table 3 shows that the ionization energy of the products, which is more than 10 eV, is large. The insulation strength of CF₄ gas is approximately 39% of SF₆, and the insulation performance of C₂F₆ is approximately 80% of SF₆. The insulation performance of SF₆ is close to C₃F₈, whereas C₄F₁₀ has insulation properties that are even better than SF₆. The liquefaction temperature of the decomposition products is lower than that of C₆F₁₂O, and the concentration of the product is much lower than that of C₆F₁₂O. The main products are Perfluorinated compounds (PFCs), which impact the environment [29]. However, the GWP of the product is less than that of SF₆. Thus, the product does not damage the environment.

4. Conclusions

The present study explores the decomposition products of C₆F₁₂O/N₂ gas mixture at 0.10 MPa under AC breakdown voltage. The decomposition process of C₆F₁₂O is calculated by DFT. The main conclusions are as follows:

The breakdown voltage of 3% C₆F₁₂O and N₂ mixed gas at 0.10 MPa is 1.9 times that of pure N₂. The decomposition products after gas breakdown include CF₄, C₂F₆, C₃F₆, C₃F₈, C₄F₁₀, and C₅F₁₂, and include the surface detection in the sphere electrode of C, O, and F, in which the number of C atoms increases. The experimental results show that the 3% C₆F₁₂O and N₂ mixed gas did not show a downward trend over 100 times breakdown tests under a 0.10 MPa breakdown voltage.

The decomposition process of C₆F₁₂O is calculated, and the C–C and C–F bonds in the C₆F₁₂O molecule break down to form the free radicals CF₃, C₂F₅, and C₃F₇, as well as F atoms, in which the four kinds of C–C bonds have a minimal difference in the energy of breaking bonds.

The decomposition products of C₆F₁₂O have an ionization energy greater than 10 eV. The GWP values of decomposition products are all less than that of SF₆; hence, they have no significant impact on the environment. The products C₂F₆, C₃F₈, and C₄F₁₀ can still maintain high insulation performance; thus, the breakdown voltage does not decrease after 100 breakdowns.