Phosphorus pentachloride Lewis structures

The largest class of molecules to violate the octet rule consists of species in which the central atom is surrounded by more than four pairs of valence electrons. Typical molecules of this type are phosphorus pentachloride, PC15, and sulfur hexafluoride, SF6. The Lewis structures of these molecules are... 

The Lewis structure of the PCI, molecule is shown in (22), and we see that it obeys the octet rule. However, when phosphorus trichloride reacts with more chlorine (Fig. 2.10), phosphorus pentachloride, a pale yellow crystalline solid, is produced ... 

Phosphorus pentachloride is an ionic solid consisting of PC14+ cations and PC16 anions, and it sublimes at 160°C to a gas of PCI, molecules. The Lewis structures of the polyatomic ions and the molecule are shown in (33). Although the cation is a polyatomic ion in which the P atom does not need to expand its valence shell, in the anion the P atom has expanded its valence shell to 12 electrons, by making use of two of its 3d-orbitals. In PC15, the P atom has expanded its valence shell to 10 electrons by using one 3d-orbital. 

Solid phosphorus pentachloride exists as PC14+PC16. Write the Lewis structures for the two ions and predict their shapes from VSEPR theory. 

First we will consider phosphorus pentachloride (PC15). The traditional Lewis structure for PC15 (assuming d orbital participation)... 

In contrast to the low yield when hydrogen chloride is employed, an 88% yield of 2,4,6-triphenyl- 1,3,5-triazine (7) is obtained when chlorosulfonic acid is used as catalyst in a molecular ratio of 3 1 (CiSOjH/PhCN) at 0-5 C C and a reaction time of 12 to 24 hours.174 Trifluo-romethanesulfonic acid as a catalyst and solvent trimerizes benzonitrile at 91 °C in a yield of 66%.175 Lewis acids alone, such as aluminum, zinc, iron or titanium chlorides, phosphorus pentachloride, and boron trifluoride, have a considerably lower catalytic activity than the corresponding mixtures of Lewis acid with various promotors, such as mineral acids, organic acids and water. These differences are attributed to a change in the structure of the active complexes with the aryl cyanides. 

Phosphorus pentachloride, a key industrial compound with annual world production of about 2X lO kg, is used to make other compounds. It reacts with sulfur dioxide to produce phosphorus oxychloride (POCI3) and thionyl chloride (SOCI2). Draw a Lewis structure and name the molecular shape of each product. 

To illustrate the treatment of a molecule in which the central atom exceeds the octet rule, consider the bonding in the phosphorus pentachloride molecule (PCI5). The Lewis structure... 

Practice Problem A Draw the Lewis structure of phosphorus pentachloride (PCI5). Practice Problem B Draw the Lewis structure of antimony pentafluoride (SbF,). 

Draw the Lewis electron dot structure of phosphorus pentachloride (PCI5). 

What is the molecularstructure of phosphorus pentachloride (PCI5). (See Example 6.5 and Figure 6.17b for the Lewis electron-dot structure.)... 

---