What is the most abundant compound known in inorganic chemistry?

Water is recognized as the most abundant compound in inorganic chemistry due to its prevalence in various natural environments and biological systems. It covers approximately 71% of the Earth's surface, existing in oceans, rivers, lakes, and as vapor in the atmosphere. In addition to its physical abundance, water plays crucial roles in a multitude of chemical reactions and processes, acting as a solvent, reactant, and product.

Moreover, water's unique properties, including its high specific heat, surface tension, and solvent abilities, are fundamental to sustaining life and facilitating various ecological and geochemical processes. The abundance of water is not only significant in a pure chemical sense but also highlights its importance in everyday chemical interactions and the environment.

Other compounds like carbon dioxide, ammonia, and sodium chloride are indeed important in their respective contexts within inorganic chemistry, but none match the sheer quantity and significance of water in both environmental and biological contexts.