- Chemistry (Wikipedia)
Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances. Chemistry also addresses the nature of chemical bonds in chemical compounds.
- Beryllium is a chemical element; it has symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form minerals. Gemstones high in beryllium include beryl (aquamarine, emerald, red beryl) and chrysoberyl. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays. Within the cores of stars, beryllium is depleted as it is fused into heavier elements. Beryllium constitutes about 0.0004 percent by mass of Earth’s crust. The world’s annual beryllium production of 220 tons is usually manufactured by extraction from the mineral beryl, a difficult process because beryllium bonds strongly to oxygen.
- Epic of Gilgamesh (Wikipedia)
The Epic of Gilgamesh (/ˈɡɪlɡəmɛʃ/) is an epic poem from ancient Mesopotamia. The literary history of Gilgamesh begins with five Sumerian poems about Bilgamesh (Sumerian for “Gilgamesh”), king of Uruk, dating from the Third Dynasty of Ur (c. 2100 BC). These independent stories were later used as source material for a combined epic in Akkadian. The first surviving version of this combined epic, known as the “Old Babylonian” version, dates back to the 18th century BC and is titled after its incipit, Shūtur eli sharrī (“Surpassing All Other Kings”). Only a few tablets of it have survived. The later Standard Babylonian version compiled by Sîn-lēqi-unninni dates from the 13th to the 10th centuries BC and bears the incipit Sha naqba īmuru (“He who Saw the Abyss”, lit. ‘“He who Sees the Unknown”’). Approximately two-thirds of this longer, twelve-tablet version have been recovered. Some of the best copies were discovered in the library ruins of the 7th-century BC Assyrian king Ashurbanipal.
- Boron (Wikipedia)
Boron is a chemical element; it has symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the boron group it has three valence electrons for forming covalent bonds, resulting in many compounds such as boric acid, the mineral sodium borate, and the ultra-hard crystals of boron carbide and boron nitride.
- Lithium (Wikipedia)
Lithium (from Ancient Greek λίθος (líthos) ‘stone’) is a chemical element; it has symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid element. Like all alkali metals, lithium is highly reactive and flammable, and must be stored in vacuum, inert atmosphere, or inert liquid such as purified kerosene or mineral oil. It exhibits a metallic luster. It corrodes quickly in air to a dull silvery gray, then black tarnish. It does not occur freely in nature, but occurs mainly as pegmatitic minerals, which were once the main source of lithium. Due to its solubility as an ion, it is present in ocean water and is commonly obtained from brines. Lithium metal is isolated electrolytically from a mixture of lithium chloride and potassium chloride.