The correct spelling of the word "astatide" refers to a hypothetical negative ion of astatine, which is a highly radioactive element. The IPA phonetic transcription for this word is /ˈæstətaɪd/. This means that the first syllable is pronounced with the short "a" sound and the second syllable is pronounced with the long "i" sound. The final syllable is pronounced with the "d" sound. The spelling of astatide is important in the field of chemistry as it helps in communicating precise scientific information.