| Sulfur trioxide | |
|---|---|
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| Other names | Sulfuric anhydride Sulfan Sulphur trioxide Sulfur trioxide |
| Identifiers | |
| CAS number | 7446-11-9 |
| Properties | |
| Molar mass | 80. CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 06 g mol−1 |
| Density | 1. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 92 g cm−3 |
| Melting point |
16. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. 9 °C, 62. 4 °F |
| Boiling point |
45 °C, 113 °F |
| Solubility in other solvents | Hydrolysis |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
−397. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. The standard enthalpy of formation or "standard heat of formation" of a compound is the change of Enthalpy that accompanies the formation of 1 mole of a 77 kJ/mol |
| Standard molar entropy S |
256. In Chemistry, the standard molar entropy is the Entropy content of one mole of substance under standard conditions (not standard temperature and pressure 77 J. K−1. mol−1 |
| Hazards | |
| EU classification | Corrosive (C) |
| R-phrases | R14, R35, R37 |
| S-phrases | S1/2, S26, S30, S45 |
| Related compounds | |
| Related compounds | SO2 H2SO4 SO2Cl2 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Sulfur trioxide (also spelled sulphur trioxide) is the chemical compound with the formula SO3. Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 In the gaseous form, this species is a significant pollutant, being the primary agent in acid rain. Acid rain is Rain or any other form of precipitation that is unusually Acidic It has harmful effects on plants aquatic animals and infastructure It is prepared on massive scale as a precursor to sulfuric acid. Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid.
Contents |
Structure and bonding
Gaseous SO3 is a trigonal planar molecule of D3h symmetry, as predicted by VSEPR theory. In Chemistry, trigonal planar is a Molecular geometry with one atom at the center and three atoms at the corners of a triangle all in one plane Valence shell electron pair repulsion (VSEPR theory (1957 is a model in Chemistry, which is used for predicting the shapes of individual Molecules based
In terms of electron-counting formalisms, the sulfur atom has an oxidation state of +6, a formal charge of 0, and is surrounded by 6 electron pairs. From the perspective of molecular orbital theory, most of these electron pairs are non-bonding in character, as is typical for hypervalent molecules. In Chemistry, molecular orbital theory ( MO theory) is a method for determining molecular structure in which Electrons are not assigned to individual A hypervalent molecule is a Molecule that contains one or more typical elements ( group 1 2 13-18 formally bearing more than eight Electrons in their
Sulfur trioxide also exhibits resonance. Resonance in Chemistry is a theory used to represent and model certain types of non-classical Molecular structures Resonance is a key component
Chemical reactions
SO3 is the anhydride of H2SO4. In Chemistry, an anhydride is a compound that can be considered as derived from another compound by subtracting the molecules of water. Thus, the following reaction occurs:
The reaction occurs both rapidly and exothermically. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity The mole (symbol mol) is a unit of Amount of substance: it is an SI base unit, and almost the only unit to be used to measure this At or above ~340 °C, sulfuric acid, sulfur trioxide, and water coexist in significant equilibrium concentrations.
Sulfur trioxide also reacts with sulfur dichloride to yield the useful reagent, thionyl chloride. Sulfur dichloride is the Chemical compound with the formula SCl2 A reagent or reactant is a substance or compound consumed during a Chemical reaction. Thionyl chloride (or thionyl dichloride) is an Inorganic compound with the formula S[[Oxygen O]] Cl 2
- SO3 + SCl2 → SOCl2 + SO2
Sulfur Trioxide reacts with water to create sulfuric acid, though the reaction is too violent to be used in large-scale manufacturing. Water is a common Chemical substance that is essential for the survival of all known forms of Life. Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid.
SO3 is a strong Lewis acid readily forming crystalline complexes with pyridine , dioxane and trimethylamine which can be used as sulfonating agents[1]. Parameters work only in their own section When a parameter is not needed please leave it empty when a parameter is wrong just clear Trimethylamine is an Organic compound with the formula N(CH33
Preparation
Sulfur trioxide can be prepared in the laboratory by the two-stage pyrolysis of sodium bisulfate:
- 1) dehydration
- 2NaHSO4 → Na2S2O7 + H2O @ 315°C
- 2) cracking
- Na2S2O7 → Na2SO4 + SO3 @ 460°C
This method will work for other metal bisulfates, the controlling factor being the stability of the intermediate pyrosulfate salt. Pyrolysis is the Chemical decomposition of organic materials by heating in the absence of Oxygen or any other reagents except possibly Steam Sodium bisulfate, also sodium hydrogen sulfate, has the Chemical formula NaHSO4
Industrially SO3 is made by the contact process. The contact process is the current method of producing Sulfuric acid in the high concentrations needed for industrial processes Sulfur dioxide, generally made by the burning of sulfur or iron pyrite (a sulfide ore of iron), is first purified by electrostatic precipitation. Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 The purified SO2 is then oxidised by atmospheric oxygen at between 400 and 600 °C over a catalyst consisting of vanadium pentoxide V2O5 activated with potassium oxide K2O on kieselguhr or silica support. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Vanadium (vəˈneɪdiəm is a Chemical element that has the symbol V and Atomic number 23 An oxide is a Chemical compound containing at least one Oxygen atom as well as at least one other element Vanadium(V oxide ( vanadia) is the Chemical compound with the formula V2O5 Diatomaceous earth (ˌdaɪətəˈmeɪʃəs ˈɝθ also known as DE, TSS, diatomite, diahydro, kieselguhr, kieselgur and The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide Platinum also works very well but is too expensive and is poisoned (rendered ineffective) much more easily by impurities.
The majority of sulphur trioxide made in this way is converted into sulfuric acid not by the direct addition of water, with which it forms a fine mist, but by absorption in concentrated sulfuric acid and dilution with water of the produced oleum. Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid. Oleum ( Latin oleum = "oil" or fuming sulfuric acid refers to a solution various compositions of Sulfur trioxide in Sulfuric
Structure of solid SO3
The nature of solid SO3 is a surprisingly complex area because of structural changes caused by traces of water. Ball-and-stick models and Space-filling models (also known as Calotte models) are 3D or spatial Molecular models which serve to display the structure [2] Upon condensation of the gas, absolutely pure SO3 condenses into a trimer, which is often called γ-SO3. This molecular form is a colorless solid with a melting point of 16. 8 °C. It adopts a cyclic structure described as [S(=O)2(μ-O)]3[3].
If SO3 is condensed above 27 °C, then α-"SO3" forms, which has a melting point of 62. 3°C. α-SO3 is fibrous in appearance, like asbestos (with which it has no chemical relationship). Structurally, it is the polymer [S(=O)2(μ-O)]n. A polymer is a large Molecule ( Macromolecule) composed of repeating Structural units typically connected by Covalent Chemical bonds Each end of the polymer is terminated with OH groups (hence α-"SO3" is not really a form of SO3). β-SO3, like the alpha form, is fibrous but of different molecular weight, consisting of an hydroxyl-capped polymer, but melts at 32. 5 °C. Both the gamma and the beta forms are metastable, eventually converting to the stable alpha form if left standing for sufficient time. This conversion is caused by traces of water[4].
Relative vapor pressures of solid SO3 are alpha< beta< gamma at identical temperatures, indicative of their relative molecular weights. The molecular mass (abbreviated m of a substance, more commonly referred to as molecular weight and abbreviated as MW, is the Mass of one Liquid sulfur trioxide has vapor pressure consistent with the gamma form. Thus heating a crystal of α-SO3 to its melting point results in a sudden increase in vapor pressure, which can be forceful enough to shatter a glass vessel in which it is heated. This effect is known as the "alpha explosion. "[4]
SO3 is aggressively hygroscopic. Hygroscopy is the ability of a substance to attract Water Molecules from the surrounding environment through either absorption or Adsorption In fact, the heat of hydration is sufficient that mixtures of SO3 and wood or cotton can ignite. In such cases, SO3 dehydrates these carbohydrates. Carbohydrates (from ' Hydrates of Carbon ' or saccharides ( Greek σάκχαρον meaning " Sugar " are the most [4]
Sources
See also
References
- ^ Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A. A hypervalent molecule is a Molecule that contains one or more typical elements ( group 1 2 13-18 formally bearing more than eight Electrons in their Parameters work only in their own section When a parameter is not needed please leave it empty when a parameter is wrong just clear Frank Albert Cotton ( April 9 1930 – February 20 2007) was the W Sir Geoffrey Wilkinson ( 14 July 1921 &ndash 26 September, 1996) was an English Chemist. ; Bochmann, Manfred (1999). Advanced Inorganic Chemistry (6th Edn. ) New York:Wiley-Interscience. ISBN 0-471-19957-5.
- ^ Holleman, A. F. ; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- ^ Advanced Inorganic Chemistry by Cotton and Wilkinson, 2nd ed p543
- ^ a b c Merck Index of Chemicals and Drugs, 9th ed. monograph 8775
Dictionary
sulfur trioxide
-noun
- (inorganic chemistry) A corrosive liquid, SO3, which forms sulfuric acid on contact with water; made commercially by the oxidation of sulfur dioxide.
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