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!
The Milky Way is a barred spiral galaxy that has a diameter usually considered to be about 100,000â120,000 light-years but may be 150,000â180,000 light-years. The Milky Way is estimated to contain 100â400 billion stars. There are likely at least 100 billion planets in the Milky Way.