Some compounds that are important nonaqueous solvents require special conditions and apparatus for their handling. Ammonia, sulfur dioxide, hydrogen fl uoride, and dinitrogen tetroxide are all gases at room temperature and atmospheric pressure. Some of the solvents such as liquid hydrogen cyanide are extremely toxic. In view of these diffi culties, it may seen unusual that so much work has been carried out in nonaqueous solvents. However, in many cases, the advantages outweigh the disadvantages. The scope of reactions that can be carried out in nonaqueous solvents is very broad indeed because there is such a difference in the characteristics of the solvents. Some of frequently used nonaqueous solvents are listed in Table 10.1 along with their relevant properties.