Carl Viktor Eduard Riecke (1.12.1845-11.06.1915) was a German physicist. He was born in Stuttgart. He studied at the University of Tübingen, in 1871 received the degree of Doctor of Philosophy at the University of Göttingen, where he worked (professor from 1873 and director of the Institute of Physics from 1881).
His work concerned crystallography, ferromagnetism, hydrodynamics, thermodynamics, physical chemistry, the study of phenomena in cathode tubes, the theory of pyro- and piezoelectricity, and the conductivity of metals. He suggested (1898) that the neutral atoms of a metal, bound in a crystal lattice, are partly ionised into positive ions and negative electrons, and constructed a theory of the conductivity of metals (the Riecke theory).