The spelling of "monomercurion" can be confusing, but it follows phonetic rules. The first syllable is "mono," pronounced as "mɒnəʊ." The second syllable is "mercu," pronounced as "mɜːkjʊ." And the final syllable is "rion," pronounced as "raɪən." The word refers to a compound containing only one mercury atom. Its spelling may seem complicated, but understanding the phonetic transcription can make it easier to remember and pronounce.
The univalent mercurous ion.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.