C-sharp minor
This key occurs more often in piano music. Domenico Scarlatti wrotetwo keyboard sonatas in C-sharp minor, K. 246 and K. 247. But after Beethoven's famous Moonlight Sonata, the key became more popular for piano. Beethoven used this key again in the outer movements of his String Quartet No. 14 (Op. 131, 1826). However, Johannes Brahms rewrote his C-sharp minor Piano Quartet to be published as Piano Quartet No. 3 in C minor, Op. 60. One of the most famous pieces in this key is Chopin's Fantaisie-Impromptu. Other works include Chopin's Nocturnes  No. 7 (Op. 27, No. 1) and No. 20 (Op. posth.), and his "Raindrop" Prelude in D-flat major (Op. 28, No. 15). Waltz in C sharp minor (op.64 No.2) is another well known musical piece from Chopin that uses this particular key (along with D flat minor key). Another very famous example of a work in C sharp minor is Rachmaninoff's Prelude in C-sharp minor (Op. 3, No. 2).