Rhaec or Rheic: How To spell?

The word Rhaec is misspelled against Rheic, an adjective meaning "Pertaining to, or designating, an acid (commonly called chrysophanic acid) found in rhubarb (Rheum)."

Word contains consecutive vowels 'EI' in between alphabets rh & c is misspelled as 'AE'
Wrong Spelling:  rh-ae-c 
Correct Spelling:  rh-ei-c 
Explore spell check of Rheic to spell without errors.