Fluorine oxygen compounds with

Although many attempts have been made to isolate this element it has probably never been obtained in the free state, unless the colorless gas obtained by G. J. and Th. Knox, by the decomposition of mercury fiuo-ride and of bydrofiuoric acid in vessels of fluor-spar was the element Fluorine forms compounds with all the other elements except oxygen. 

Chlorine reacts with most elements, both metals and non-metals except carbon, oxygen and nitrogen, forming chlorides. Sometimes the reaction is catalysed by a trace of water (such as in the case of copper and zinc). If the element attacked exhibits several oxidation states, chlorine, like fluorine, forms compounds of high oxidation state, for example iron forms iron(III) chloride and tin forms tin(IV) chloride. Phosphorus, however, forms first the trichloride, PCI3, and (if excess chlorine is present) the pentachloride PCI5. 

In contrast to phosphorus esters, sulfur esters are usually cleaved at the carbon-oxygen bond with carbon-fluorine bond formation Cleavage of esteri nf methanesulfonic acid, p-toluenesidfonic acid, and especially trifluoromethane-sulfonic acid (tnflic acid) by fluoride ion is the most widely used method for the conversion of hydroxy compounds to fluoro derivatives Potassium fluoride, triethylamine trihydrofluoride, and tetrabutylammonium fluoride are common sources of the fluoride ion For the cleavage of a variety of alkyl mesylates and tosylates with potassium fluoride, polyethylene glycol 400 is a solvent of choice, the yields are limited by solvolysis of the leaving group by the solvent, but this phenomenon is controlled by bulky substituents, either in the sulfonic acid part or in the alcohol part of the ester [42] (equation 29)... 

Hydrogen bonds can exist in many molecules other than HF, H20, and NH3. The basic requirement is simply that hydrogen be bonded to a fluorine, oxygen, or nitrogen atom with at least one unshared pair. Consider, for example, the two compounds whose condensed structural formulas are... 

Oxygen and fluorine ions have very similar ionic radii. This steric similarity ensures relatively easy substitution of the oxygen in the compounds, by fluorine ions. Such substitution opens up huge possibilities for the synthesis of oxyfluoride compounds with desired crystal structure and properties. 

Since niobates and tantalates belong to the octahedral ferroelectric family, fluorine-oxygen substitution has a particular importance in managing ferroelectric properties. Thus, the variation in the Curie temperature of such compounds with the fluorine-oxygen substitution rate depends strongly on the crystalline network, the ferroelectric type and the mutual orientation of the spontaneous polarization vector, metal displacement direction and covalent bond orientation [47]. Hence, complex tantalum and niobium fluoride compounds seem to have potential also as new materials for modem electronic and optical applications. 

Typical examples of compounds with a coordination-type structure are Nb02F and Ta02F, which crystallize in a Re03 type structure [233, 243]. Oxygen and fluorine ions are statistically distributed in the anionic sub-lattice. The compounds are characterized by X Me = 3 and can be described as MeX3 type compounds. 

It is a simple matter to predict that oxygen will form a stable compound with two fluorine atoms, F20. The orbital representation is ... 

The oxidation number of oxygen is —2 in most of its compounds. Exceptions are its compounds with fluorine (in which case, the previous statement takes precedence) and its occurrence as peroxides (022-), superoxides (02 ), and ozonides (03 ). 

Nevertheless, as early as 1933 it was suggested that xenon might form stable compounds with the most electronegative elements, fluorine and oxygen. Early attempts to react xenon directly with fluorine were unsuccessful, and chemists ignored this possibility for the next 30 years. 

C09-0136. Sulfur forms neutral compounds with oxygen, fluorine, and chlorine that display a variety of steric... 

In combustion calorimetry [47,48] the enthalpies of chemical reactions of elements and compounds with reactive gases like oxygen or fluorine are determined. 

In the 1960s, scientists first produced compounds of xenon and some other noble gases at the Argonne National Laboratory located near Chicago. Xenon and krypton are the only noble gases that readily form compounds with oxygen and fluorine. For instance, when xenon combines with fluorine, it can form a series of compounds, such as xenon difluoride PCeF ), xenon tetra-fluoride (XeF ), and xenon hexafluoride pCeF ). These and other compounds of xenon are formed within metal containers at high temperatures and pressures. They are not stable. 

Noble Gas-Oxygen Compounds. Since the discovery in 1962 that the noble gases are not truly chemically inert, propellant chemists became intrigued with the possibility that they could serve as excellent carriers of oxygen (and fluorine) and thus generate a new family of chemical propellants. While the importance of this discovery to chemistry cannot be underestimated, so far it has not led to the preparation of new compounds as significant rocket oxidizers. 

---