Difference between revisions of "Chlorine"
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|appearance= Greenish gas | |appearance= Greenish gas | ||
<!-- Periodic table --> | <!-- Periodic table --> | ||
| − | |above= | + | |above=[[Fluorine|F]] |
| − | |below= | + | |below=[[Bromine|Br]] |
| − | |left= | + | |left=[[Sulfur]] |
| − | |right= | + | |right=[[Argon]] |
| − | |number= | + | |number=17 |
| − | |atomic mass= | + | |atomic mass=35.45 |
|atomic mass 2= | |atomic mass 2= | ||
|atomic mass ref= | |atomic mass ref= | ||
| Line 34: | Line 34: | ||
|series comment= | |series comment= | ||
|series color= | |series color= | ||
| − | |group= | + | |group= 17 |
|group ref= | |group ref= | ||
| − | |group comment= | + | |group comment=(halogens) |
| − | |period= | + | |period=17 |
|period ref= | |period ref= | ||
|period comment= | |period comment= | ||
| − | |block= | + | |block=p |
|block ref= | |block ref= | ||
|block comment= | |block comment= | ||
| − | |electron configuration= | + | |electron configuration=[Ne] 3s<sup>2</sup> 3p<sup>5</sup> |
|electron configuration ref= | |electron configuration ref= | ||
|electron configuration comment= | |electron configuration comment= | ||
| − | |electrons per shell= | + | |electrons per shell=2, 8, 7 |
|electrons per shell ref= | |electrons per shell ref= | ||
|electrons per shell comment= | |electrons per shell comment= | ||
<!-- Physical properties --> | <!-- Physical properties --> | ||
|physical properties comment= | |physical properties comment= | ||
| − | |color= | + | |color=Pale green |
| − | |phase= | + | |phase=Gas |
|phase ref= | |phase ref= | ||
|phase comment= | |phase comment= | ||
| − | |melting point K= | + | |melting point K=171.6 |
| − | |melting point C= | + | |melting point C=−101.5 |
| − | |melting point F= | + | |melting point F=−150.7 |
|melting point ref= | |melting point ref= | ||
|melting point comment= | |melting point comment= | ||
| − | |boiling point K= | + | |boiling point K=239.11 |
| − | |boiling point C= | + | |boiling point C=−34.04 |
| − | |boiling point F= | + | |boiling point F=−29.27 |
|boiling point ref= | |boiling point ref= | ||
|boiling point comment= | |boiling point comment= | ||
| Line 70: | Line 70: | ||
|sublimation point ref= | |sublimation point ref= | ||
|sublimation point comment= | |sublimation point comment= | ||
| − | |density gplstp= | + | |density gplstp=3.2 |
|density gplstp ref= | |density gplstp ref= | ||
|density gplstp comment= | |density gplstp comment= | ||
| Line 85: | Line 85: | ||
|density gpcm3mp ref= | |density gpcm3mp ref= | ||
|density gpcm3mp comment= | |density gpcm3mp comment= | ||
| − | |density gpcm3bp= | + | |density gpcm3bp=1.5625 |
|density gpcm3bp ref= | |density gpcm3bp ref= | ||
|density gpcm3bp comment= | |density gpcm3bp comment= | ||
| Line 100: | Line 100: | ||
|triple point 2 ref= | |triple point 2 ref= | ||
|triple point 2 comment= | |triple point 2 comment= | ||
| − | |critical point K= | + | |critical point K=416.9 |
| − | |critical point MPa= | + | |critical point MPa=7.991 |
|critical point ref= | |critical point ref= | ||
|critical point comment= | |critical point comment= | ||
| − | |heat fusion= | + | |heat fusion=6.406 |
|heat fusion ref= | |heat fusion ref= | ||
|heat fusion comment= | |heat fusion comment= | ||
| Line 110: | Line 110: | ||
|heat fusion 2 ref= | |heat fusion 2 ref= | ||
|heat fusion 2 comment= | |heat fusion 2 comment= | ||
| − | |heat vaporization= | + | |heat vaporization=20.41 |
|heat vaporization ref= | |heat vaporization ref= | ||
|heat vaporization comment= | |heat vaporization comment= | ||
| − | |heat capacity= | + | |heat capacity=33.949 |
|heat capacity ref= | |heat capacity ref= | ||
|heat capacity comment= | |heat capacity comment= | ||
| Line 119: | Line 119: | ||
|heat capacity 2 ref= | |heat capacity 2 ref= | ||
|heat capacity 2 comment= | |heat capacity 2 comment= | ||
| − | |vapor pressure 1= | + | |vapor pressure 1=128 |
| − | |vapor pressure 10= | + | |vapor pressure 10=139 |
| − | |vapor pressure 100= | + | |vapor pressure 100=153 |
| − | |vapor pressure 1 k= | + | |vapor pressure 1 k=170 |
| − | |vapor pressure 10 k= | + | |vapor pressure 10 k=197 |
| − | |vapor pressure 100 k= | + | |vapor pressure 100 k=239 |
|vapor pressure ref= | |vapor pressure ref= | ||
|vapor pressure comment= | |vapor pressure comment= | ||
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<!-- Atomic properties --> | <!-- Atomic properties --> | ||
|atomic properties comment= | |atomic properties comment= | ||
| − | |oxidation states= | + | |oxidation states='''7''', 6, '''5''', 4, 3, 2, '''1''', '''−1''' |
|oxidation states ref= | |oxidation states ref= | ||
| − | |oxidation states comment= | + | |oxidation states comment=(a strongly acidic oxide) |
| − | |electronegativity= | + | |electronegativity=3.16 |
|electronegativity ref= | |electronegativity ref= | ||
|electronegativity comment= | |electronegativity comment= | ||
| − | |ionization energy 1= | + | |ionization energy 1=1251.2 |
|ionization energy 1 ref= | |ionization energy 1 ref= | ||
|ionization energy 1 comment= | |ionization energy 1 comment= | ||
| − | |ionization energy 2= | + | |ionization energy 2=2298 |
|ionization energy 2 ref= | |ionization energy 2 ref= | ||
|ionization energy 2 comment= | |ionization energy 2 comment= | ||
| − | |ionization energy 3= | + | |ionization energy 3=3822 |
|ionization energy 3 ref= | |ionization energy 3 ref= | ||
|ionization energy 3 comment= | |ionization energy 3 comment= | ||
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|atomic radius calculated ref= | |atomic radius calculated ref= | ||
|atomic radius calculated comment= | |atomic radius calculated comment= | ||
| − | |covalent radius= | + | |covalent radius=102±4 |
|covalent radius ref= | |covalent radius ref= | ||
|covalent radius comment= | |covalent radius comment= | ||
| − | |Van der Waals radius= | + | |Van der Waals radius=175 |
|Van der Waals radius ref= | |Van der Waals radius ref= | ||
|Van der Waals radius comment= | |Van der Waals radius comment= | ||
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|crystal structure prefix= | |crystal structure prefix= | ||
|crystal structure ref= | |crystal structure ref= | ||
| − | |crystal structure comment= | + | |crystal structure comment=Orthorhombic |
|crystal structure 2= | |crystal structure 2= | ||
|crystal structure 2 prefix= | |crystal structure 2 prefix= | ||
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|thermal expansion at 25 ref= | |thermal expansion at 25 ref= | ||
|thermal expansion at 25 comment= | |thermal expansion at 25 comment= | ||
| − | |thermal conductivity= | + | |thermal conductivity=8.9×10<sup>−3</sup> |
|thermal conductivity ref= | |thermal conductivity ref= | ||
|thermal conductivity comment= | |thermal conductivity comment= | ||
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|electrical resistivity at 0 ref= | |electrical resistivity at 0 ref= | ||
|electrical resistivity at 0 comment= | |electrical resistivity at 0 comment= | ||
| − | |electrical resistivity at 20= | + | |electrical resistivity at 20=>10 |
|electrical resistivity at 20 ref= | |electrical resistivity at 20 ref= | ||
|electrical resistivity at 20 comment= | |electrical resistivity at 20 comment= | ||
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|Curie point ref= | |Curie point ref= | ||
|Curie point comment= | |Curie point comment= | ||
| − | |magnetic ordering= | + | |magnetic ordering=Diamagnetic |
|magnetic ordering ref= | |magnetic ordering ref= | ||
|magnetic ordering comment= | |magnetic ordering comment= | ||
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|Brinell hardness ref= | |Brinell hardness ref= | ||
|Brinell hardness comment= | |Brinell hardness comment= | ||
| − | |CAS number= | + | |CAS number=7782-50-5 |
|CAS number ref= | |CAS number ref= | ||
|CAS number comment= | |CAS number comment= | ||
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|first isolation date ref= | |first isolation date ref= | ||
|first isolation date= | |first isolation date= | ||
| − | |discovery and first isolation by= | + | |discovery and first isolation by=Carl Wilhelm Scheele (1774) |
|named by= | |named by= | ||
|named date ref= | |named date ref= | ||
Revision as of 20:49, 10 October 2017
 Chlorine gas in an ampoule. | |||||
| General properties | |||||
|---|---|---|---|---|---|
| Name, symbol | Chlorine, Cl | ||||
| Appearance | Greenish gas | ||||
| Chlorine in the periodic table | |||||
| |||||
| Atomic number | 17 | ||||
| Standard atomic weight (Ar) | 35.45 | ||||
| Group, block | (halogens); p-block | ||||
| Period | period 17 | ||||
| Electron configuration | [Ne] 3s2 3p5 | ||||
per shell | 2, 8, 7 | ||||
| Physical properties | |||||
| Pale green | |||||
| Phase | Gas | ||||
| Melting point | 171.6 K (−101.5 °C, −150.7 °F) | ||||
| Boiling point | 239.11 K (−34.04 °C, −29.27 °F) | ||||
| Density at (0 °C and 101.325 kPa) | 3.2 g/L | ||||
| when liquid, at | 1.5625 g/cm3 | ||||
| Critical point | 416.9 K, 7.991 MPa | ||||
| Heat of fusion | 6.406 kJ/mol | ||||
| Heat of | 20.41 kJ/mol | ||||
| Molar heat capacity | 33.949 J/(mol·K) | ||||
| pressure | |||||
| Atomic properties | |||||
| Oxidation states | 7, 6, 5, 4, 3, 2, 1, −1 (a strongly acidic oxide) | ||||
| Electronegativity | Pauling scale: 3.16 | ||||
| energies |
1st: 1251.2 kJ/mol 2nd: 2298 kJ/mol 3rd: 3822 kJ/mol | ||||
| Covalent radius | 102±4 pm | ||||
| Van der Waals radius | 175 pm | ||||
| Miscellanea | |||||
| Crystal structure | Orthorhombic | ||||
| Thermal conductivity | 8.9×10−3 W/(m·K) | ||||
| Electrical resistivity | >10 Ω·m (at 20 °C) | ||||
| Magnetic ordering | Diamagnetic | ||||
| CAS Registry Number | 7782-50-5 | ||||
| Discovery and first isolation | Carl Wilhelm Scheele (1774) | ||||
Chlorine is the second-lightest halogen, with the symbol Cl and atomic number 17. It has a sickly green colour and a distinctive smell, recognizable to many at low concentrations as 'the smell of pool centers' due to its compounds use as a water disinfecting agent.
Contents
Properties
Chemical
Chlorine is a strong oxidizer with 7 valence electrons. Its unstable electron configuration results in high reactivity. Because of this, chlorine usually exists on earth in the form of a halide salt, and free chlorine is rare. Like fluorine, elemental chlorine forms a highly reactive diatomic gas.[1] Chlorine, like other halogens, forms many oxoanions, negatively charged ions containing oxygen. Most notably, these are hypochlorite(ClO-), chlorite(ClO2-), chlorate(ClO3-), and perchlorate(ClO4-).
Unlike hydrochloric acid, elemental chlorine easily corrodes copper, especially in moist air.[2]
Physical
Chlorine is a yellow-greenish gas, with a powerful odor similar to that of boiling hypochlorite solutions. It is heavier than air, and slightly soluble in water, 3.26 g/L.
Availability
While liquid (as in liquefied, and not aqueous solution) chlorine is sold by gas companies, it is hard to get hold of as it's very toxic and corrosive.
Chlorine is better produced from OTC products.
Production
There are many methods to generating chlorine gas, due to it being such a commonly used ion.
Potassium permanganate will oxidize hydrochloric acid to chlorine gas, as will manganese dioxide. In both cases, manganese(II) chloride will be produced as well.
A hypochlorite and hydrochloric acid will produce chlorine; either a solution of sodium hypochlorite or calcium hypochlorite. A violent reaction with a lot of foam may take place in the case of the latter, and starting small scale is a must to get a sense for the reaction before any large scale chlorine production is attempted.
A popular way of making chlorine on Sciencemadness is using hydrochloric acid and trichloroisocyanuric acid (TCCA). TCCA can be found as slow release chlorine tablets for swimming pools. This reaction is favorable because it not too expensive, produces a large amount of chlorine over an extended period of time (while hypochlorites tend to violently produce all the chlorine right on mixing with the acid), leaves no awful byproducts (such as MnO2) and the reaction speed at standard concentrations and temperatures is not too fast nor too slow for most applications.
Projects/Experiments
Chlorine can be used to produce anhydrous metal chlorides, such as aluminum(III) chloride, iron(II) or iron(III) chloride, and many others, which cannot be made in solution, due to formation of hydrates which are irreversible, and decompose to the metal oxide and HCl gas upon heating.
- 2 Al + 3 Cl2 → 2 AlCl3
- 2 Fe + 3 Cl2 → 2 FeCl3
Other projects:
- Make hypochlorites
- Make sulfur dichloride
- Make disulfur dichloride
- Make interhalogen compounds
- Alkane halogenation
Handling
Safety
Elemental chlorine is extremely toxic and corrosive to many common metals. Because it is heavier than air, it tends to accumulate at the bottom of poorly ventilated spaces. Chlorine gas is a strong oxidizer, which may react with flammable materials. It is notorious for reacting with iron at high temperatures, in a strong exothermic reaction, known as chlorine-iron fire.
Storage
Liquefied chlorine must be stored in cold places, away from any source of heat. Chlorine can be liquefied at room temperature, at a pressure of 7.4 bar.
Chlorine releasing chemicals, such as bleach and TCCA should be stored in closed bottles, usually covered with a bag or in a box, that must be opened form time to time to release the pressure.
The storage area for both chemicals should not contain any metal parts susceptible to chlorine attack.
Disposal
As it is toxic and has an irritating smell, it is recommended to neutralize chlorine before disposing of it. In gaseous form, elemental chlorine can be neutralized with ammonia, reaction that produces nitrogen gas and ammonium chloride.
Aqueous chlorine however, should never be neutralized with ammonia, as it will generate toxic chloramines. Acids should also be avoided. Hydrogen peroxide will neutralize bleach and release oxygen. Ascorbic acid and its salts are also good at neutralizing chlorine. Other good neutralizing agents are certain sulfur compounds, such as bisulfites, metabisulfites, thiosulfites.
References
- ↑ "Handbook of Toxicology of Chemical Warfare Agents", Academic Press, 2009, p. 313.
- ↑ Handbook of Corrosion Data, by Bruce D. Craig, David S. Anderson, p. 271
