C6H4O5

The molecular formula C6H4O5 may refer to:
 * 2,5-Furandicarboxylic acid
 * 2,4-Furandicarboxylic acid
 * 3,4-Furandicarboxylic acid
 * Trihydroxybenzoquinone
 * 2,3,5-Trihydroxy-1,4-benzoquinone
 * 3,4,5-Trihydroxy-1,2-benzoquinone
 * 3,4,6-Trihydroxy-1,2-benzoquinone