Physical properties halogens

What Accounts for the Regular Changes in the Halogens Physical Properties ... 

Table 11.1 and Table 11.2 (p. 314) give some of the physical properties of the common halogens. Figure 11.1 shows graphically some of the properties given in Table 11.1, together with enthalpies of atomisation. 

Di- and poly-halogenated aliphatic hydrocarbons. No general procedure can be given for the preparation of derivatives of these compounds. Reliance must be placed upon their physical properties (b.p., density and refractive index) and upon any chemical reactions which they undergo. 

TABLE B Selected Physical Properties of Representative Organic Halogen Compounds... 

The physical properties of the halogen fluorides are given in Table 1. Calculated thermodynamic properties can be found in Reference 24. 

Vlayl fluoride [75-02-5] (VF) (fluoroethene) is a colorless gas at ambient conditions. It was first prepared by reaction of l,l-difluoro-2-bromoethane [359-07-9] with ziac (1). Most approaches to vinyl fluoride synthesis have employed reactions of acetylene [74-86-2] with hydrogen fluoride (HF) either directly (2—5) or utilizing catalysts (3,6—10). Other routes have iavolved ethylene [74-85-1] and HF (11), pyrolysis of 1,1-difluoroethane [624-72-6] (12,13) and fluorochloroethanes (14—18), reaction of 1,1-difluoroethane with acetylene (19,20), and halogen exchange of vinyl chloride [75-01-4] with HF (21—23). Physical properties of vinyl fluoride are given ia Table 1. 

The tnhahdes of phosphoms usually are obtained by direct halogenation under controlled conditions, eg, in carbon disulfide solution in the case of the triiodide. Phosphoms trifluoride [7647-19-0] is best made by transhalogenation of PCl using AsF or Cap2. AH of the phosphoms tnhahdes are both Lewis bases and acids. The phosphoms tnhahdes rapidly hydroly2e in water and are volatile. Examination by electron diffraction has confirmed pyramidal stmctures for the gaseous tnhahde molecules (36). Physical properties and heat of formation of some phosphoms hahdes are hsted in Table 7. 

Flame retardants designated for nylon include halogenated organic compounds, phosphorous derivatives, and melamine cyanurate (160—163). Generally, flame retardants are difficult to spin in nylon because of the high loading required for effectiveness and their adverse effects on melt viscosity and fiber physical properties. 

Table 3 gives the corresponding physical properties of some commercially important substituted pyridines having halogen, carboxyHc acid, ester, carboxamide, nitrile, carbiaol, aminomethyl, amino, thiol, and hydroxyl substituents. 

Zirconium tetrabromide [13777-25-8] ZrBr, is prepared direcdy from the elements or by the reaction of bromine on a mixture of zirconium oxide and carbon. It may also be made by halogen exchange between the tetrachloride and aluminum bromide. The physical properties are given in Table 7. The chemical behavior is similar to that of the tetrachloride. 

Zirconium tetraiodide [13986-26-0], Zrl, is prepared directly from the elements, by the reaction of iodine on zirconium carbide, or by halogen exchange with aluminum triiodide. The reaction of iodine with zirconium oxide and carbon does not proceed. The physical properties are given in Table 7. 

Properties and Applieations. Aryloxyphosphazene elastomers using phenoxy and J-ethylphenoxy substituents have found interest in a number of appHcations involving fire safety. This elastomer has a limiting oxygen index of 28 and contains essentially no halogens. It may be cured using either peroxide or sulfur. Peroxide cures do not require the allyhc cute monomer. Gum physical properties are as follows (17) ... 

Atomic and physical properties Table 17.4 Physical properties of the halogens... 

In general the compounds have properties intermediate between those of the parent halogens, though a combination of aggressive chemical reactivity and/or thermal instability militates against the determination of physical properties such as mp, bp, etc., in some instances. However, even for such highly dissociated species as BrCl, precise molecular (as distinct from bulk) properties can be determined by spectroscopic techniques. Table 17.12 summarizes some of the more important physical properties of the... 

Table 17.14 Physical properties of the higher halogen fluorides...

Table 17.27 Some physical properties of halogen fluorosulfates ...

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