The preparation, from a Zintl-phase with a semimetal, of a high-pressure phase in which the coordination in the semimetal partial structure is no longer reconcilable with the Zintl-Klemm concept has been accomplished for the first time with LiGe. At normal pressure LiGe can still be classed under the Zintl phases, whereas LiSn can no longer be so classified. The LiGe high-pressure phase crystallizes in a novel structure type, which is made up of layers containing two- and four-coordinate germanium and which shows close relationships to the structures in LiSn and LiPb.