Fluorine is the chemical element with atomic number 9, represented by the symbol F. Fluorine forms a single bond with itself in elemental form, resulting in the diatomic F2 molecule. F2 is a supremely reactive, poisonous, pale, yellowish brown gas. Elemental fluorine is the most chemically reactive and electronegative of all the elements. For example, it will readily "burn" hydrocarbons at room temperature, in contrast to the combustion of hydrocarbons by oxygen, which requires an input of energy with a spark. Therefore, molecular fluorine is highly dangerous, more so than other halogens such as the poisonous chlorine gas.
Fluorine's highest electronegativity and small atomic radius give unique properties to many of its compounds. For example, the enrichment of 235-Uranium, the principal nuclear fuel, relies on the volatility of Uranium hexafluoride. Also, the carbon–fluorine bond is one of the strongest bonds in organic chemistry. This contributes to the stability and persistence of fluoroalkane based organofluorine compounds, such as PTFE/(Teflon) and PFOS. The carbon–fluorine bond's inductive effects result in the strength of many fluorinated acids, such as triflic acid and trifluoroacetic acid. Drugs are often fluorinated at biologically reactive positions, to prevent their metabolism and prolong their half-lives.
F2 is a corrosive pale yellow or brown gas that is a powerful oxidizing agent. It is the most reactive and most electronegative of all the elements on the classic Pauling scale and readily forms compounds with most other elements. It is found in the -1 oxidation state, except when bonded to another fluorine in F2 which gives it an oxidation number of 0. Fluorine combines with the noble gases argon, krypton, xenon, and radon. Even in dark, cool conditions, fluorine reacts explosively with hydrogen. The reaction with hydrogen can occur at extremely low temperatures, using liquid hydrogen and sorine. It is so reactive that metals, water, as well as most other substances, burn with a bright flame in a jet of fluorine gas. In moist air, it reacts with water to form the also dangerous hydrofluoric acid. Fluorides are compounds that combine fluorine with some positively charged counterpart. They often consist of crystalline ionic salts. Fluorine compounds with metals are among the most stable of salts.
Hydrogen fluoride is a weak acid when dissolved in water, but is still very corrosive
The base value of each unit of ranges between 4 and 15Ð per unit, with up to 3 units being found at any one time.
Presence on Mars: Common
|Group 1 | Group 2 | Group 3 | Group 4 | Group 5 | Group 6|
|Group 1|||Aluminum | Arsenic | Beryllium | Boron | Calcium | Cantite | Carbon | Chlorine | Chromium | Cobalt | Copper | Flourine | Helium| | Hydrogen | Iron | Lithium | Magnesium | Manganese | Nickel | Oxygen | Phosphorus | Plesium | Potassium | Silicon | Sodium||