|Relative key||E major|
|Parallel key||C-sharp major|
|Dominant key||G-sharp minor|
|C♯, D♯, E, F♯, G♯, A, B|
The C-sharp natural minor scale is:
Its relative major is E major. Its parallel major, C-sharp major, is usually replaced by D-flat major, since C-sharp major, which contains seven sharps, is not normally used. Its enharmonic equivalent, D-flat minor, having eight flats, including the B, has a similar problem. Therefore, C-sharp minor is often used as the parallel minor for D-flat major. (The same enharmonic situation occurs with the keys of A-flat major and G-sharp minor.)
There are only two known symphonies in the 18th century written in this key. One of them is by Joseph Martin Kraus, but he appears to have found the key difficult since he later rewrote it in C minor. Even in the following two centuries, C-sharp minor symphonies remained rare. Two notable examples are the first movement of Mahler's Symphony No. 5 and Prokofiev's Symphony No. 7.
This key occurs more often in piano literature from the 18th century onwards. Domenico Scarlatti wrote just two keyboard sonatas in C-sharp minor, K. 246 and K. 247. But after Beethoven's Piano Sonata No. 14 (Moonlight Sonata), the key became more frequent in the piano repertoire. Beethoven himself used this key again in the outer movements of his String Quartet No. 14 (Op. 131, 1826). Even so, Johannes Brahms still felt the need to rewrite his C-sharp minor Piano Quartet in C minor, which was published as Piano Quartet No. 3 in C minor, Op. 60.
Frédéric Chopin often wrote in this key: examples include the Fantaisie-Impromptu, Étude Op. 25, No. 7, Scherzo No. 3 (Op. 39), Waltz Op. 64, No. 2, and Nocturnes No. 7 (Op. 27, No. 1) and No. 20 (Lento con gran espressione). More examples of works in C-sharp minor include Rachmaninoff's Prelude in C-sharp minor (Op. 3, No. 2), Scriabin's Étude in C-sharp minor, Op. 2, No. 1 (Scriabin), Franz Liszt's Hungarian Rhapsody No. 2, and Tchaikovsky's Piano Sonata in C-sharp minor.
Piano concertos written in C-sharp minor include Erich Wolfgang Korngold's Piano Concerto for the Left Hand, Op. 17, Nikolai Rimsky-Korsakov's Piano Concerto, and others by Ferdinand Ries, Xaver Scharwenka, Amy Beach, Miriam Hyde and Issay Dobrowen. Dmitri Shostakovich's Violin Concerto No. 2 is in C-sharp minor.