Germanium II Sulfide Precipitated

When this test is performed, it is essential that the acid strength be not less than that stated or germanium (II) sulfide may precipitate. The formation of an orange-colored precipitate on standing is indicative not of incomplete reduction but rather of partial atmospheric oxidation of the material in solution. 

Unlike germanium(IV) sulfide, which may be precipitated by means of hydrogen sulfide only from solutions that are more acid than 6 N, germanium(II) sulfide may be obtained only from weakly acid or alkaline solutions and redissolves if the acidity is increased. When dry, ger-manium(II) sulfide is stable in air. 

Not all the (Il)iodide wiU separate from the concentrated hydriodic acid solution. The germanium in the filtrate is recovered by diluting it and precipitating germanium(II) sulfide. 

The sublimed germaniun(II) sulfide, recovered from germanite, is usually not pure but contains lead and arsenic sulfides. These are eliminated during the process of preparing the (Il)iodide and need not be removed previously. After oxidation of the residues left in the reaction flask, however, it is convenient to precipitate these elements by hydrogen sulfide from a dilute acid solution (0.2 N) before recovery of the germanium as the (IV)sulfide that is precipitated from a 6 iV acid solution. ... 

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