Silicon fluoride (SiF4)
Silicon Tetrafluoride
CAS: 7783-61-1
Molecular Formula: F4Si
Silicon fluoride (SiF4) - Names and Identifiers
Silicon fluoride (SiF4) - Physico-chemical Properties
| Molecular Formula | F4Si |
| Molar Mass | 104.08 |
| Density | 1.66 |
| Melting Point | -90°C |
| Boling Point | -86 °C |
| Water Solubility | hydrolyzed by H2O [AIR87] |
| Vapor Presure | 3517.191kPa at 25℃ |
| Appearance | colorless gas |
| Specific Gravity | 1.66 |
| Merck | 13,8575 |
| Sensitive | 8: reacts rapidly with moisture, water, protic solvents |
| Refractive Index | 1.207 |
| Physical and Chemical Properties | Silicon tetrafluoride is also known as "tetrafluorosilane". Discovered in 1771 by the famous Swedish chemist Scheele. Chemical formula sif4. Molecular weight 104.08. Colorless gas, asphyxiating odor, toxic! Melting Point -90.2 °c, boiling point -86 °c, -95.2 °c sublimation. Critical temperature -14.15 °c. Critical pressure 3.715MPA. The relative density was 4.69. Soluble in anhydrous ethanol, hydrofluoric acid and nitric acid, insoluble in ether. In the humid air hydrolysis, hydrogen fluoride and silicic acid and the formation of smoke, water hydrolysis, the formation of raw silicate H4SiO4 and hydrofluoric acid, hydrofluoric acid generated by hydrolysis with non-hydrolyzed Silicon tetrafluoride complexed fluorosilicic acid. Pure fluorosilicic acid is not present, because of its easy decomposition, only 60% of its aqueous solution can be prepared. Fluosilicic acid is stronger than sulfuric acid, is a kind of strong acid. With carbon, phosphorus, iodine and other non-metallic and zinc, Mercury, hydrogen sulfide, molten potassium chloride, anhydrous alkali metal carbonate and borate almost no reaction. Can stop the oxidation of magnesium in the air. Reaction with potassium and sodium under hot conditions produces a mixture of silicon, potassium, sodium fluoride and fluorosilicate. The reaction with aluminum chloride produces silicon tetrachloride at a high temperature. preparation method: it can be obtained by reacting concentrated sulfuric acid with silica and calcium fluoride, or by decomposing fluorine-containing phosphate ore with concentrated sulfuric acid. To obtain extremely pure silicon tetrafluoride, fluorosilicate can be thermally decomposed: BaSiF6 = BaF2 + sif4. purposes: for the preparation of organic silicides, fluorosilicic acid and aluminum fluoride, but also for chemical analysis, oil drilling, catalysts, such as fumigant. FIG. 1 shows the molecular structure of silicon tetrafluoride. |
Silicon fluoride (SiF4) - Risk and Safety
| Risk Codes | R26 - Very Toxic by inhalation R35 - Causes severe burns R34 - Causes burns R31 - Contact with acids liberates toxic gas R26/27/28 - Very toxic by inhalation, in contact with skin and if swallowed. R14 - Reacts violently with water |
| Safety Description | S7/9 - S24/25 - Avoid contact with skin and eyes. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S23 - Do not breathe vapour. |
| UN IDs | 1859 |
| WGK Germany | 3 |
| RTECS | VW2327000 |
| TSCA | Yes |
| Hazard Note | Toxic/Corrosive |
| Hazard Class | 2.3 |
Silicon fluoride (SiF4) - Reference Information
| EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
| hazard characteristics | non-flammable. It can be easily hydrolyzed into fluorosilicic acid, which forms hydrogen fluoride in humid air. It is asphyxiating, irritating and corrosive. Serious damage to the eyes, skin, mucous membranes and respiratory system. Local corrosion strong, can cause decalcification poisoning, after a long period of pain and disability. Inhalation experience caused by Dyspnea, pulmonary edema and chemical Pneumonia. At the same time visible tooth erosion caused by decalcification, due to fluoride chronic poisoning lead to bone sclerosis. Rats inhaled LC50300ppm. After heating, the pressure in the bottle increases, and there is a risk of explosion. This information was edited by chemical book Xiaonan (2015-08-17). |
| instructions for storage and transportation | in special steel bottles, stored in a cool and ventilated warehouse. Stay away from heat and fire sources. Prevent moisture and rain. "Toxic gases and corrosion products" shall be marked. Air and rail transport is strictly prohibited. Water can be used to cool the container in case of fire, close the valve and cut off the fire source. With carbon dioxide, dry powder, dry sand fire. Water use is prohibited. |
| first aid measures | when eye contact occurs, rinse with plenty of water and see a doctor for treatment. Skin contact with the first water rinse, and then apply magnesium oxide glycerin ointment, such as Burns should immediately see a doctor. When inhaling air, immediately move the patient to fresh air, rest and keep warm. The patient was sent to the hospital for treatment. |
| category | hazardous gas |
| toxicity grade | high toxicity |
| Acute toxicity | inhalation-rat LC50: 2272 PPM |
| explosive hazard characteristics | the steel cylinder can be exploded by heat and sunlight; The leakage releases highly toxic smoke |
| flammability hazard characteristics | toxic fluoride smoke from combustion |
| storage and transportation characteristics | warehouse ventilation and low temperature drying; Light loading and light unloading |
| fire extinguishing agent | water and sand mist |
| Occupational Standard | TWA 2.5 mg (fluorine)/m3 |
| toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
Last Update：2024-04-29 13:40:26
