Chinese characters
Chinese characters are primarily morphosyllabic, meaning that most Chinese morphemes are monosyllabic and are written with a single character, though in modern Chinese most words are disyllabic and dimorphemic, consisting of two syllables, each of which is a morpheme. In modern Chinese 10% of morphemes only occur as part of a given compound. However, a few morphemes are disyllabic, some of them dating back to Classical Chinese. Excluding foreign loan words, these are typically words for plants and small animals. They are usually written with a pair of phono-semantic compound characters sharing a common radical. Examples are Hu Die  hudie "butterfly" and Shan Hu  shanhu "coral". Note that the Hu  hu of hudie and the Hu  hu of shanhu have the same phonetic, Hu , but different radicals ("insect" and "jade", respectively). Neither exists as an independent morpheme except as a poetic abbreviation of the disyllabic word.
What are written with a single character?
Chinese morphemes
Chinese characters are primarily morphosyllabic, meaning that most Chinese morphemes are monosyllabic and are written with a single character, though in modern Chinese most words are disyllabic and dimorphemic, consisting of two syllables, each of which is a morpheme.
a single character