The term soprano clarinet is used occasionally to refer to those instruments from the clarinet family that occupy a higher position, both in pitch and in popularity than subsequent additions to the family such as the basset horns and bass clarinets. The B♭ clarinet is by far the most common type of clarinet and the unmodified word "clarinet" usually refers to this instrument. However, due to a tendency for writers and historians to imitate the terms used to denote instruments in other instrumental 'family groups' the term soprano is sometimes used to apply not only to the B♭ clarinet but also to the clarinets in A and C, sounding respectively a semitone lower and a whole tone higher than the B♭ instrument, and even the low G clarinet—rare in Western music but popular in the folk music of Turkey—sounding a whole tone lower than the A. While some writers reserve a separate category of sopranino clarinets for the E♭ and D clarinets, these are more usually regarded as soprano clarinets as well. All have a written range from the E below middle C to about the C three octaves above middle C, with the sounding pitches determined by the particular instrument's transposition.
It is worth bearing in mind though that the only instrument of the clarinet family whose name is undisputed and always required is that of the bass clarinet. The use of the terms 'soprano', 'piccolo', 'sopranino' etc. is, at best, relatively rare and of debatable accuracy. These terms came about specifically to distinguish the 'clarinet' from its lower pitched, younger siblings and have been applied later and only in that context. Even the term 'alto' (for the E♭ instrument a fifth below the B♭ 'soprano') is open to discussion and the alternative term 'tenor' might appear, from the point of view of pitch at least, to be more appropriate.
Orchestral composers largely write for clarinets in B♭ and A. The bass is not uncommon and the high E♭ is very occasionally called for, often referred to simply as E♭ clarinet. Clarinets in C were used likewise from the Classical era until about 1910. Wolfgang Amadeus Mozart also called for clarinets in B♮ when writing in very sharp keys (e.g. the E major arias in Idomeneo and Così fan tutte), but this became obsolete far sooner. There have also been soprano clarinets in C, A, and B♭ with curved barrels and bells marketed under the names Saxonette, Claribel, and Clariphon.
Shackleton lists also obsolete "sopranino" clarinets in (high) G, F, and E, and soprano clarinets in B♮ and A♭. The G (sopranino) clarinet, only a half step lower than the A♭ piccolo clarinet, was popular during the late 19th century in Vienna for playing Schrammelmusik. B♭ soprano clarinet is also one of the most common instruments played in beginner and high school band, alongside the bass clarinet.