sulphophosphoric

from The Century Dictionary.

• See thiophosphoric.

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

• adjective Of, pertaining to, or designating, a hypothetical sulphacid of phosphorus, analogous to phosphoric acid, and known in its salts.

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

• adjective chemistry Of, pertaining to, or designating a hypothetical thioacid of phosphorus, analogous to phosphoric acid, and known only in its salts.