Aluminum germanium—oxygen bonds

It is believed that most of the transition metals are complexed to nitrogen donors, such as are found in amino acids or derivatives of chlorophyll, and that the metals with high ionic potentials, such as beryllium, boron, germanium, titanium, gallium, and major elements such as aluminum and silicon, may be bonded to oxygen donors of degraded lignin. 

Framework silicates, also referred to as tectosilicates, are characterized by a tetrahedral ion-to-oxygen ratio of 1 2. The typical tetrahedral ions are silicon and aluminum, but, in some cases, germanium, titanium, boron, gallium, beryllium, magnesium, and zinc may substitute in these tetrahedral sites. All tetrahedral ions are typically bonded through oxygen to another tetrahedral ion. Silicon normally composes from 50% to 100% of the tetrahedral ions. 

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