Germanium disulfide refers to the chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 with the formula Ge

Germanium

Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. The isolated element is a semiconductor, with an appearance most similar to elemental silicon....

S₂

Sulfur

Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

. It is a colourless white crystalline material, which melts at roughly 800 °C.

History

Germanium sulfide was the first germanium compound found by Clemens Winkler

Clemens Winkler

Clemens Alexander Winkler was a German chemist who discovered the element germanium in 1886, solidifying Dmitri Mendeleev's theory of periodicity.- Life :...

 during the analysis of argyrodite

Argyrodite

Argyrodite is an uncommon silver germanium sulfide mineral with formula Ag8GeS6. The color is iron-black with a purplish tinge, and the lustre metallic....

.
The fact that germanium sulfide is not soluble in acidic water made it possible for Winkler to isolate the new element from the other elements.