1 For a 2-hour party, Cork Catering in Illinois charges $7.50 per guest for beer or wine only and $14.50 per guest for a premium bar serving most types of mixed drinks. 2  For detailed open bar pricing, see How Much Does an Open Bar Cost. For a 2-hour party, Cork Catering in Illinois charges $7.50 per guest for beer or wine only and $14.50 per guest for a premium bar serving most types of mixed drinks. 2  For detailed open bar pricing, see How Much Does an Open Bar Cost.
Selenium exists in a number of allotropic forms. Allotropes are forms of an element with different physical and chemical properties. One allotrope of selenium is an amorphous red powder. A lump of clay is an example of an amorphous material. A second allotrope of selenium has a bluish, metallic appearance.
The selenium atom has a radius of 120.pm and its Van der Waals radius is 190.pm. In its elemental form selenium's CAS number is 7782-49-2. Selenium was discovered and first isolated by JÃ¶ns Jakob Berzelius and Johann Gottlieb Gahn in 1817.