(1933). The Trivalency of Gallium Ions Formed during the Dissolution of the Metal in Acids

Gall ium dissolves very slowly in dilute acids such as HC1, H2804, and HC104. The rate can be substantial ly accelerated if the metal is connected with a Pt electrode in the same solution. From the volume of the hydrogen de-veloped the valency of 3 is calculated for the Ga ions going into solution. The same ionic charge is obtained from coulometric measurements using a Ga amalgam as an anode. This is in contradiction with the valency of one re-cently reported in the literature. However, microscopic observations revealed that the valency of one is only apparent, because Ga ~ disintegrates partial ly while going into solution anodically. The diameter of the smallest observable Ga particles i less than 7 x 10-5 ram. If the solution is not cooled the forma-tion of large metallic spheres is observed. Disintegration explains the devia-tion from Faraday's law, and the presence of the small particles--the reducing ability of the electrolyte. The postulation of Ga ions of lower valency is therefore, not necessary