Aluminum trichloride molecular structure

Naming becomes more difficult if the molecular complexity of a compound changes when it is fused or vaporized. Aluminum chloride is an ionic solid but vaporizes to dimeric molecules the solid is then aluminum trichloride whereas the vapor is dialuminum hexachloride. Similar considerations hold also for FeCl3, P2O5, and a number of additional compounds. Likewise, phosphorus(V) chloride is an appropriate name for PCI5 in the vapor state, but an ideal system of nomenclature should find some way of indicating that the solid consists of equal quantities of PCl and PClJf ions. It is a little difficult to decide just how much information about the structure of a compound must be included in its name before this name is to be considered adequate. 

There seems to be even less structural similarity for many other metal halides as the crystalline systems are compared with the molecules in the vapor phase. Aluminum trichloride, e.g., crystallizes in a hexagonal layer structure. Upon melting, and then, upon evaporation at relatively low temperatures, dimeric molecules are formed. At higher temperatures they dissociate into monomers (Figure 9-58) [107], The coordination number decreases from 6 to 4 and then to 3 in this process. However, at closer scrutiny, even the dimeric aluminum trichloride molecules can be derived from the crystal structure. Figure 9-59 shows another representation of crystalline aluminum trichloride which facilitates the identification of the dimeric units. A further example is chromium dichloride illustrated in Figure 9-60. The small oligomers in its vapor have structures [108] that are closely related to the solid structure [109], Correlation between the molecular composition of the vapor and their source crystal has been established for some metal halides [110],... 

Under closer scrutiny, even the dimeric aluminum trichloride molecules can be derived from the crystal structure. Figure 9-61 shows another representation of crystalline aluminum trichloride which facilitates the identification of the dimeric units. Correlation between the molecular composition of the vapor and the source crystal has been established for some metal halides [9-62]. 

Phenylbutanoyl chloride reacts in carbon disulfide with aluminum trichloride to give a ketone with molecular formula CjjjHjjO. Write the structure of the product. 

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