Silicon and other non-metal elements from Group 14

Carbon (C), silicon (Si) and germanium (Ge) are members of the Group 14 elements; C is a non-metal while Si and Ge are metalloids. All have a strong propensity for covalent bonding. Their oxides (CO2, SiO2, GeO2) dissolve to form weak acids in aqueous media. Carbon is abundant in the atmosphere and essential to life. Silicon is ubiquitous in the Earth's crust and beneficial to plants, while Ge is a non-essential microelement. Inorganic C, Si and Ge constitute a trilogy of great interest in soil science and biogeochemistry: C and Si interact closely in terrestrial, marine and global biogeochemical cycles, while Ge is a relevant tracer for Si in these cycles.