* "a" is not a recognized chemical symbol: Chemical formulas use symbols for elements from the periodic table. There is no element with the symbol "a".
* "II" is a Roman numeral: Roman numerals are sometimes used in naming compounds to indicate the oxidation state of a metal, but they are not part of the formula itself.
* "3" is a subscript: Subscripts indicate the number of atoms of a particular element in a compound.
To determine a valid compound, you need to know the correct symbols for the elements involved.
For example, if you meant AlI3, this would represent Aluminum Iodide.
Let me know if you have a different formula in mind, and I can help you identify the compound.
