ثانى أكسيد الكبريت
| الأسماء | |
|---|---|
|
اسم أيوپاك
Sulfur dioxide
| |
| أسماء أخرى
Sulfurous anhydride
Sulfur(IV) oxide | |
| تمييز | |
| رقم CAS | [] |
| PubChem | |
| رقم EC | |
| KEGG | |
| عناوين مواضيع طبية MeSH | |
| ChEBI | |
| رقم RTECS | WS4550000 |
| SMILES |
|
| InChI | InChI=1/O2S/c1-3-2 |
| مرجع بايلستاين | 3535237 |
| مرجع Gmelin | 1443 |
| الخصائص | |
| الصيغة الجزيئية | SO 2 |
| كتلة مولية | 64.066 g mol−1 |
| المظهر | Colorless gas |
| الرائحة | Pungent; similar to a just-struck match |
| الكثافة | 2.6288 kg m−3 |
| نقطة الانصهار |
-72 °C, 201 K, -98 °F |
| نقطة الغليان | |
| قابلية الذوبان في الماء | 94 g/L forms sulfurous acid |
| ضغط البخار | 237.2 kPa |
| الحموضة (pKa) | 1.81 |
| القاعدية (pKb) | 12.19 |
| القابلية المغناطيسية | −18.2·10−6 cm3/mol |
| اللزوجة | 0.403 cP (at 0 °C) |
| البنية | |
| إحداثية | Digonal |
| الشكل الجزيئي | Dihedral |
| Dipole moment | 1.62 D |
| الكيمياء الحرارية | |
|
للتشكل ΔfH |
−296.81 kJ mol−1 |
|
entropy S |
248.223 J K−1 mol−1 |
| المخاطر | |
|
تبويب الاتحاد الاوروپي (DSD)
|
T |
| توصيف المخاطر | R23, R34, R50 |
| تحذيرات وقائية | (S1/2), S9, S26, S36/37/39, S45 |
| (معيـَّن النار) |
|
| الجرعة أوالهجريز القاتل (LD, LC): | |
|
LC50 (الهجريز الأوسط)
|
3000 ppm (mouse, 30 min) 2520 ppm (rat, 1 hr) |
|
LCLo (المنشورة الأقل)
|
993 ppm (rat, 20 min) 611 ppm (rat,خمسة hr) 764 ppm (mouse, 20 min) 1000 ppm (human,عشرة min) 3000 ppm (human,خمسة min) |
| حدود التعرض الصحية بالولايات المتحدة (NIOSH): | |
|
PEL (المسموح)
|
TWAخمسة ppm (13 mg/m3) |
|
REL (الموصى به)
|
TWA 2 ppm (5 mg/m3) STخمسة ppm (13 mg/m3) |
|
IDLH (خطر عاجل)
|
100 ppm |
| مركبات ذا علاقة | |
|
sulfur oxides ذات العلاقة
|
Sulfur monoxide Sulfur trioxide |
|
مركـّبات ذات علاقة
|
Ozone Selenium dioxide |
|
ما لم يُذكر غير ذلك، البيانات المعطاة للمواد في حالاتهم العيارية (عند 25 °س [77 °ف]، 100 kPa). | |
verify (what is  ?)
| |
| مراجع الجدول | |
ثاني أوكسيد الكبريت مركّب كيمياوي بالصيغة SO2. هذا الغاز المهم يعتبر الناتج الرئيسي من إحتراق الكبريت.
SO2 ينتج بواسطة البراكين وفي العمليات الصناعية المتنوعة. ولأن الفحم والنفط يحتويان على كمّيات مختلفة من مركّبات الكبريت، فبالتالى يولّد إحتراقهم ثاني أوكسيد كبريت.
Structure and bonding
SO2 is a bent molecule with C2vsymmetry point group. A valence bond theory approach considering just s and p orbitals would describe the bonding in terms of resonance between two resonance structures.
The sulfur–oxygen bond has a bond order of 1.5. There is support for this simple approach that does not invoke d orbital participation. In terms of electron-counting formalism, the sulfur atom has an oxidation state of +4 and a formal charge of +1.
التواجد
As an air pollutant
Sulfur dioxide is a noticeable component in the atmosphere, especially following volcanic eruptions. According to the United States Environmental Protection Agency, the amount of sulfur dioxide released in the U.S. per year was:
| Year | SO2 |
|---|---|
| 1970 | 31,161,000 طن صغيرs (28.3 مج.طن) |
| 1980 | 25,905,000 طن صغيرs (23.5 مج.طن) |
| 1990 | 23,678,000 طن صغيرs (21.5 مج.طن) |
| 1996 | 18,859,000 طن صغيرs (17.1 مج.طن) |
| 1997 | 19,363,000 طن صغيرs (17.6 مج.طن) |
| 1998 | 19,491,000 طن صغيرs (17.7 مج.طن) |
| 1999 | 18,867,000 طن صغيرs (17.1 مج.طن) |
Sulfur dioxide is a major air pollutant and has significant impacts upon human health. In addition, the concentration of sulfur dioxide in the atmosphere can influence the habitat suitability for plant communities, as well as animal life. Sulfur dioxide emissions are a precursor to acid rain and atmospheric particulates. Due largely to the US EPA’s Acid Rain Program, the U.S. has had a 33% decrease in emissions between 1983 and 2002. This improvement resulted in part from flue-gas desulfurization, a technology that enables SO2 to be chemically bound in power plants burning sulfur-containing coal or oil. In particular, calcium oxide (lime) reacts with sulfur dioxide to form calcium sulfite:
- CaO + SO2 → CaSO3
Aerobic oxidation of the CaSO3 gives CaSO4, anhydrite. Most gypsum sold in Europe comes from flue-gas desulfurization.
Sulfur can be removed from coal during burning by using limestone as a bed material in fluidized bed combustion.
Sulfur can also be removed from fuels before burning, preventing formation of SO2 when the fuel is burnt. The Claus process is used in refineries to produce sulfur as a byproduct. The Stretford process has also been used to remove sulfur from fuel. Redox processes using iron oxides can also be used, for example, Lo-Cat or Sulferox.
Fuel additives such as calcium additives and magnesium carboxylate may be used in marine engines to lower the emission of sulfur dioxide gases into the atmosphere.
As of 2006, China was the world's largest sulfur dioxide polluter, with 2005 emissions estimated to be 25,490,000 طن صغيرs (23.1 مج.طن). This amount represents a 27% increase since 2000, and is roughly comparable with U.S. emissions in 1980.
Ingestion
In the United States, the Center for Science in the Public Interest lists the two food preservatives, sulfur dioxide and sodium bisulfite, as being safe for human consumption except for certain asthmatic individuals who may be sensitive to them, especially in large amounts. Symptoms of sensitivity to sulfiting agents, including sulfur dioxide, manifest as potentially life-threatening trouble breathing within minutes of ingestion.
See also
- Sulfur trioxide
- Sulfur–iodine cycle
- National Ambient Air Quality Standards
== المراجع ==
- ^ Sulfur dioxide, U.S. National Library of Medicine
- ^ نطقب:RubberBible87th
- ^ NIOSH Pocket Guide to Chemical Hazards 0575
- ^ نطقب:IDLH
- ^ Cunningham, Terence P.; Cooper, David L.; Gerratt, Joseph; Karadakov, Peter B. & Raimondi, Mario (1997). "Chemical bonding in oxofluorides of hypercoordinatesulfur". Journal of the Chemical Society, Faraday Transactions. 93 (13): 2247–2254. doi:10.1039/A700708F.
- ^ Volcanic Gases and Their Effects. Volcanoes.usgs.gov. Retrieved on 2011-10-31.
- ^ National Trends in Sulfur Dioxide Levels, United States Environmental Protection Agency.
- ^ Sulfur Dioxide. United States Environmental Protection Agency
- ^ Hogan, C. Michael (2010). "Abiotic factor" in Encyclopedia of Earth. Emily Monosson and C. Cleveland (eds.). National Council for Science and the Environment. Washington DC
- ^ Lindeburg, Michael R. (2006). Mechanical Engineering Reference Manual for the PE Exam. Belmont, C.A.: Professional Publications, Inc. pp. 27–3. ISBN .
- ^ FAQ’s About Sulfur Removal and Recovery using the LO-CAT® Hydrogen Sulfide Removal System. gtp-merichem.com
- ^ Process screening analysis of alternative gas treating and sulfur removal for gasification. (December 2002) Report by SFA Pacific, Inc. prepared for U.S. Department of Energy (PDF) . Retrieved on 2011-10-31.
- ^ May, Walter R. Marine Emissions Abatement. SFA International, Inc., p. 6.
- ^ China has its worst spell of acid rain, United Press International (2006-09-22).
- ^ "Center for Science in the Public Interest – Chemical Cuisine". Retrieved March 17, 2010.
- ^ "California Department of Public Health: Food and Drug Branch: Sulfites" (PDF). Archived from the original (PDF) on July 23, 2012. Retrieved September 27, 2013.
وصلات خارجية
 |
مشاع الفهم فيه ميديا متعلقة بموضوع sulfur dioxide. |
- Global map of sulfur dioxide distribution
- United States Environmental Protection Agency Sulfur Dioxide page
- International Chemical Safety Card 0074
- IARC Monographs. "Sulfur Dioxide and some Sulfites, Bisulfites and Metabisulfites" v54. 1992. p131.
- NIOSH Pocket Guide to Chemical Hazards
- CDC – Sulfure Dioxide – NIOSH Workplace Safety and Health Topic
- Sulfur Dioxide, Molecule of the Month
