1 Coordination compounds are complexes that consist of one or more central atoms or ions with one or more attached molecules. 2  The central atom is called a metal, and is a Lewis Acid; 3  The attached ions are ligands, and are Lewis Bases;  The total number of attachments between metal and ligands is the coordination number.
Stars are not scattered randomly through space, they are gathered together into vast groups known as galaxies. The Sun belongs to a galaxy called the Milky Way. Astronomers estimate there are about 100 thousand million stars in the Milky Way alone. Outside that, there are millions upon millions of other galaxies also!
Astronomers now believe there may be many more red dwarf stars â the most common type of star in the universe â than previously thought. Based on the latest estimates, astronomers estimate our universe could be the home to 300 sextillion stars.