Halides, binary decomposition

Halides, 7 1-26 actinide elements, 2 195-233 anion dependence, 39 139 berkelium, 28 48, 51-53 beryllium, 14 255-332 binary, 35 237-246, 274-280 decomposition, 35 277 dichalcogen dihalides, 35 279-280 equilibrium studies, 35 242 mixed-ligand halides, 35 244-246 reactions, 35 246 selenium halides, 35 240-241... 

Double Decomposition.—Many binary compounds may be regarded as salts of definite binary acids as well as compounds formed by the union of two elements. Among such compounds are the metallic halides, sulfides, selenides, tellurides, and peroxides. Many salts of these acids may be made by neutralizing a soluble base with the appropriate acid a much larger number may be made by the method of double decomposition (Exercise 15). 

Reaction of Alcohol and Hydrobromic Acid.—The third reaction which proves the presence of the hydroxyl group in alcohol is with the halogen binary acids. When hydrochloric, or better hydrobromic or hydriodic acid, acts upon hot alochol a partial decomposition of the alcohol takes place and the ethyl halide and water are formed... 

The deposition of either niobium or tantalum boride by CVD is difficult to accomplish, when compared with other binary metal boride compositions. In early attempts a reaction mixture containing the metal and boron halides and Hi was used as a precursor stream. However, this reaction frequently leads to the formation of a deposit which had undergone phase separation into fractions consisting of elemental metal and boron, rather than the metal boride. The reaction only produced metal boride if very low flow rates (< 0.4 mis ) were selected [243]. Alternatively, the thermal decomposition of BBr3 and MBrs (M = Nb, Ta) has been used to deposit NbBi andTaB2 [244]. However, this reaction requires temperatures in excess 1500°C. Mixtures of tantalum pentachloride, TaCIs, and diborane, B2H6, decompose at 500-900°C to yield TaB2 films [245]. 

Binary Compounds and Related Systems.—Halides. The thermal decomposition and reduction by H2 of WCI4 and lower tungsten chlorides have been studied by t.g.a. and X-ray diffraction spectroscopy, and the phase WCl2.6(s) has been... 

Binary halides are best made by action of HF, HCl, Bt2 or I2 on hot Zn ZnF2 is also prepared by thermal decomposition of Zn(BF4)2- The vapours of the halides contain linear molecules. Solid ZnF2 adopts a rutile structure (Figure 6.21) and has a high lattice energy and melting... 

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