There are many ways you can describe a compound in order to search for it within a database. Consider your options and what types of descriptions the particular database will accept. If you get zero results, try another way before moving on to another resource.
CAS Registry Number
For example, consider ethanol:
These resources collect information on the most commonly encountered compounds and their most basic properties. If you are not finding an entry under the first chemical name that you try, try another synonym for that same compound or in the case of some of the sources, draw the structure of the compound you are looking for. Then try one of the more comprehensive sources (other tabs) or contact Jeremy (contact info on the right) if you are still having trouble finding the data you need.
Both Wikipedia and Wolfram Alpha can be quick and easy to seach when it come to chemical and physical properties. But before you use these resources, please consider the following when searching each source.