Pengguna:Agung.karjono/Bak pasir/Timbal(II) nitrat: Perbedaan revisi

Tag: Suntingan visualeditor-wikitext
Tag: Suntingan visualeditor-wikitext
{{Unsur|Belerang|S|16}} Belerang [[Kelimpahan unsur|melimpah]], [[Valensi|multivalen]] dan bersifat [[nonlogam]]. Di bawah [[Temperatur dan tekanan standar|kondisi normal]], belerang membentuk molekul oktatomik siklik dengan rumus kimia [[oktasulfur|{{Chem|S|8}}]]. Unsur belerang berwarna kuning cerah, berbentuk [[kristal]] padat pada suhu ruang.
 
Belerang adalah unsur paling umum kesepuluh berdasarkan massa di alam semesta, dan unsur kelima paling umum di Bumi. Meskipun kadang-kadang ditemukan dalam bentuk [[mineral unsur alami|asli]] dan murni, belerang di Bumi biasanya terjadi sebagai [[mineral sulfida]] dan [[Mineral sulfat|sulfat]]. Bentuk aslinya melimpah, belerang dikenal di zaman kuno, disebutkan untuk penggunaannya di [[India kuno]], [[Yunani kuno]], [[Sejarah Tiongkok#Zaman kuno|Tiongkok]], dan [[Mesir kuno|Mesir]]. Secara historis dan dalam literatur belerang juga disebut '''brimstone''',<ref name=Greenwd/> yang berarti "batu yang terbakar".<ref>{{cite EB1911 |wstitle=Brimstone |volume=4 |page=571}}</ref>
Sulfur is the tenth most common element by mass in the universe, and the fifth most common on Earth. Though sometimes found in pure, [[native element minerals|native]] form, sulfur on Earth usually occurs as [[sulfide minerals|sulfide]] and [[sulfate minerals]]. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in [[ancient India]], [[ancient Greece]], [[history of China#Ancient China|China]], and [[ancient Egypt|Egypt]]. Historically and in literature sulfur is also called '''brimstone''',<ref name=Greenwd/> which means "burning stone".<ref>{{cite EB1911 |wstitle=Brimstone |volume=4 |page=571}}</ref> Today, almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from [[natural gas]] and [[petroleum]]. The greatest commercial use of the element is the production of [[sulfuric acid]] for sulfate and phosphate [[fertilizer]]s, and other chemical processes. The element sulfur is used in [[match]]es, [[insecticide]]s, and [[fungicide]]s. Many sulfur compounds are odoriferous, and the smells of odorized natural gas, skunk scent, grapefruit, and garlic are due to [[organosulfur]] compounds. [[Hydrogen sulfide]] gives the characteristic odor to rotting eggs and other biological processes.
 
Sulfur is an [[mineral (nutrient)|essential element]] for all life, but almost always in the form of [[organosulfur compounds|organosulfur]] compounds or metal sulfides. Three [[amino acid]]s ([[cysteine]], [[cystine]], and [[methionine]]) and two vitamins ([[biotin]] and [[thiamine]]) are organosulfur compounds. Many [[cofactor (biochemistry)|cofactors]] also contain sulfur, including [[glutathione]], [[thioredoxin]], and [[iron–sulfur protein]]s. [[Disulfide]]s, S–S bonds, confer mechanical strength and insolubility of the protein [[keratin]], found in outer skin, hair, and feathers. Sulfur is one of the core chemical elements needed for [[biochemical]] functioning and is an elemental [[macronutrient]] for all living organisms.