hexatomic

from The Century Dictionary.

• In chem., consisting of six atoms: also applied to atoms which are hexavalent and to alcohols or other compounds having six replaceable hydrogen atoms.

from the GNU version of the Collaborative International Dictionary of English.

• adjective rare Having six atoms in the molecule.
• adjective Having six replaceable radicals.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective chemistry Having six atoms in each molecule