1-Naphthalenol, 3,4-dihydro-, also known as 3,4-Dihydro-1(2H)-naphthalenone or alpha-Tetralone, is a cyclic ketone derived from naphthalene where two hydrogen atoms have been added to the 3 and 4 positions of the naphthalene ring, and a ketone group is present at the 1 position. It is a colorless to pale yellow solid with a melting point of 49-52°C.