In this case, chemistry of Ga and Ge are a bit different, and the Cr compound that was misstated is part of a family of materials that rely heavily on the coordinating chemistry of Ge and its mates in the same period. So it makes more sense. If indeed it were Ga, that would be an interesting compound that probably wouldn't look anything like the material families being discussed by these authors.

I think the reader and the writer share the burden of accurate communication. The reader should ideally come prepared and the writer should provide as best they can. A prepared reader makes quick work of this typo.