Molecular Compounds
A molecular compound is a compound comprised of only non-metal and metalloid elements. No metals are found in these binary compounds. The presence of a metal would make these binary compounds automatically an ionic compound. That's how you tell the difference: An ionic compound has a metal or a group in it. If there is no metal or group, the compound is molecular.
These compounds are connected by covalent bonds. Covalent bonds are bonds in which electrons are shared between elements. Because these molecular compounds are fundamentally different from ionic compounds, the naming system is different. When naming these compounds, we use Greek prefixes to tell how many of each element we have. Charges on these elements can therefore be ignored. The numerical Greek prefixes are listed to the right. Naming Molecular Compounds When naming these compounds, we use special rules: 1) Name the first element in the compound. If there is more than one of this element, signify this with the appropriate Greek prefix. 2) Follow this with the second element with the appropriate prefix and an -ide ending. *** The prefix mono- is not needed on the first element if it is single, however, it must be placed on the second element of the compound.*** Examples: |
SO2 - sulfur dioxide
N2O5 - dinitrogen pentaoxide OCl - oxygen monochloride (not monoxygen monochloride - mono is left off the first element) silicon tetrabromide - SiBr4 |