Iridium rhymes with:
chriptosporidium, cryptosporidium, nephridium, chriptosporidium, cryptosporidium, idiom, nephridium, presidium, chriptosporidium, compendium, cryptosporidium, idiom, indium, medium, myocardium, nephridium, odiaum, palladium, plasmodium, podium, presidium, radium, rhodium, sodium, stadium, tedium, vanadium
Iridium sounds like:
ireton, irradiation, irritation