Fluorine forms

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. 

Sihcon and boron bum ia fluorine forming siUcon tetrafluoride [7783-61-17, SiF, and boron trifluoride [7637-07-2] respectively. Selenium and tellurium form hexafluorides, whereas phosphoms forms tri- or pentafluorides. Fluorine reacts with the other halogens to form eight interhalogen compounds (see Fluorine compounds, inorganic-halogens). 

Fluorine forms very reactive halogen fluorides. Reaction of CI2 and F2 at elevated temperatures can produce GIF, CIF, or CIF 3 be obtained from the reaction of Br2 and F2. These halogen fluorides react with all nonmetals, except for the noble gases, N2, and O2 (5). Fluorine also forms a class of compounds known as hypofluorites, eg, CF OF (6). Fluorine peroxide [7783-44-0], O2F2, has also been reported (6). 

There are a number of complex chlorides of three general types M(MnCl2), M2(MnCl, and M4(MnClg). M is monovalent in each case. Fluorine forms only 9M(MnF.) and the only complex bromine compound reported is Ca(MnBt 4H2O. There are no iodide complexes. The anhydrous salt, MnCl2, forms cubic pink crystals, and three well-defined hydrates exist. Aqueous solubiUties of the tetrahydrate and dihydrate ate given in Table 7. 

We can expect the effects just discussed to be at work in the bonds fluorine forms with other ele-... 

Consider the fluorides of the second-row elements. There is a continuous change in ionic character of the bonds fluorine forms with the elements F, O, N, C, B, Be, and Li. The ionic character increases as the difference in ionization energies increases (see Table 16-11). This ionic character results in an electric dipole in each bond. The molecular dipole will be determined by the sum of the dipoles of all of the bonds, taking into account the geometry of the molecule. Since the properties of the molecule are strongly influenced by the molecular dipole, we shall investigate how it is determined by the molecular architecture and the ionic character of the individual bonds. For this study we shall begin at the left side of the periodic table. 

The examples just mentioned include two elements, fluorine and lithium. Fluorine forms a weakly bound molecular solid. Lithium forms a metallic solid. Let us see how we can account for this extreme difference, applying the principles of bonding treated in Chapter 16. 

CIO, CI02, CIO,, and C104 in many chemical stockrooms. However fluorine forms no stable oxoanions and iodine is never found as I04. Explain these observations. 

The magnetic criterion is particularly valuable because it provides a basis for differentiating sharply between essentially ionic and essentially electron-pair bonds Experimental data have as yet been obtained for only a few of the interesting compounds, but these indicate that oxides and fluorides of most metals are ionic. Electron-pair bonds are formed by most of the transition elements with sulfur, selenium, tellurium, phosphorus, arsenic and antimony, as in the sulfide minerals (pyrite, molybdenite, skutterudite, etc.). The halogens other than fluorine form electron-pair bonds with metals of the palladium and platinum groups and sometimes, but not always, with iron-group metals. 

C09-0083. Fluorine forms compounds whose chemical formula is XF4 with elements from groups 14, 16, and 18. Determine the Lewis structure, describe the shape, and draw a ball-and-stick model of Gep4, SeF4, and Xep4. 

C09-0132. Sulfur and fluorine form seven different molecules SF2, SSF2, FSSF, F3 SSF, SF4, F5 SSF5, and SFg. Draw the Lewis structure of each molecule, and identify the geometry around each inner sulfur atom. 

Polymers with a sizable number of ionic groups and a relatively nonpolar backbone are known as ionomers. The term was first used for copolymers of ethylene with carboxylated monomers (such as methacrylic acid) present as salts, and cross-linked thermoreversibly by divalent metal ions. Such polymers are useful as transparent packaging and coating materials. Their fluorinated forms have been made into very interesting ion-exchange membranes (considered further below). 

When heated in air at 800°C AS4S4 vapors begin to dissociate to AS2S2 which then ignites to form arsenic oxides. Ignition in chlorine produces arsenic chloride. Reaction with fluorine forms arsenic trifluoride. It is stable in water and also in the air at ambient temperatures. It does not react with hot concentrated HCl but is decomposed by nitric acid. It forms thioarsenite ion, AsS3 and elemental arsenic when warmed with caustic soda solution. Similar reaction occurs with sodium sulfide. 

Nonmetals, such as sulfur, phosphorus and carbon (amorphous) inflame in fluorine forming their corresponding fluoro compounds, such as sulfur hexafluoride (SFe), phosphorus pentafluoride (PF5), and carbon tetrafluoride (CF4). 

Fluorine also reacts with other halogens, forming interhalogen compounds. While with bromine and iodine it reacts vigorously at ordinary temperatures, with chlorine the reaction occurs at 200°C. Such interhalogen products with these halogens include iodine heptafluoride, bromine trifluoride, bromine pentafluoride, and chlorine trifluoride. Metalloid elements, such as arsenic, silicon, selenium, and boron also inflame in a stream of fluorine, forming fluorides. 

It combines with fluorine, forming iodine heptafluoride ... 

Reaction with fluorine forms an unstable compound, fluorine nitrate , NO3F ... 

Sodium combines with all halogens forming sodium hahdes. The metal ignites with fluorine, forming hydrogen fluoride. Thin metal film reacts readily with chlorine and bromine at ordinary temperatures. Molten sodium burns in chlorine producing sodium chloride. The metal reacts with iodine, only in vapor phase, forming sodium iodide. 

Lithium and fluorine form a diatomic molecule that has a large dipole moment in the gas phase it has been measured to be 6.3248 D in the ground vibrational state. The equilibrium intemuclear distance is 1.564 A, and, therefore, the apparent... 

Fluorine and sodium are only two atomic numbers apart on the periodic table. Why, then, does fluorine form an anion, F , whereas sodium forms a cation, Na" " ... 

Lebeau and Damiens obtained the simplest fluorocarbon carbon tetrafluoride (CF4), separating it from fluorine formed at a carbon anode during electrolysis of beryllium difluoride (the first organic product from electrochemical fluorination). 

Steroids with enone units in ring A64 or ring D72 were successfully fluorinated forming the corresponding vicinal ra-difluorides without affecting other parts of the molecules, e.g. 12 -> 13 and 14 -> 15. 

It is well established that hydrogen forms more than one covalenl binary compound with carbon. Fluorine behaves similarly. Thus, fluorine forms CFi. C>F4. CjFV,. C.rFx and many higher hontologs. as well as the definitely imerstiiial compound (CF) . The other halogens form some similar compounds, although 10 more limited extent, and various polyhalogen compounds have been prepared. They exhibit the maximum covalencv of four and are therefore inert to hydrolysis and most other low temperature chemical reactions. 

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