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 contains over 200 billion stars, and enough dust and gas to make billions more. The solar system lies about 30,000 light-years from the galactic center, and about 20 light-years above the plane of the galaxy. More than half the stars found in the Milky Way are older than the 4.5 billion year old sun.