Fluoride - Fluoride A fluoride is a binary compound of fluorine with another element or radical. Examples of common fluoride compounds include hydrofluoric acid (HF), and sodium fluoride (NaF). Table of contents showTocToggle("show","hide") 1 Uses 2 Fluorides and human health 2.1 High concentrations 2.2 Low concentrations 3 The fluoridation debate 3.3 Possible side effects of low concentration intake 3.4 Industrial conspiracy 3.5 Court cases 3.6 Cities and countries' choices on fluoridation 3.7 Secondary effects of fluoridation 3.8 Conclusion on controversy 4 External Links 4.9 Pro fluoridation 4.10 Anti fluoridation 4.11 Research sites Uses Fluoride compounds are used in a wide range of applications. Where instead used in very low concentrations (on the order of parts per million), fluorides are used in human health applications; specifically, fluorides such as.
Radon fluoride - Radon fluoride Radon fluoride (RnF) is a compound of radon, an inert or noble gas. Inert gases are chemically unreactive because their outermost electron shells are completely filled with electrons. However, radon reacts readily with fluorine. The forces between radon's outermost electrons and the atomic nucleus are weakened by distance and the interference of other electrons, enough that the energy gained in creating a radon fluoride molecule is greater than the energy required for promotion of the reaction. The compound is chemically stable, although a powerful oxidizing agent. The usefulness of radon compounds is limited because the longest-lived isotope of radon has a half-life of only 3.82 days..
Venus (planet) - Carbonyl sulfide Hydrogen chloride Hydrogen fluoride trace Venus is the second planet from the Sun, named after the Roman goddess Venus. It is a terrestrial planet, very similar in size and bulk composition to Earth; it is sometimes called Earth's "sister planet" as a result of this similarity. Sometimes (inaccurately) referred to as the "morning star" or the "evening star", it is by far the brightest "star" in the sky. Because Venus is closer to the Sun than Earth is, it is always in roughly the same direction as the Sun, so on Earth it can only be seen just before sunrise or just after sunset. Physical characteristics Atmosphere Venus has an atmosphere consisting mainly of carbon dioxide and a small amount of nitrogen, with a pressure at the surface about.
Ionic crystal - their electrostatic attraction. Examples of such crystals are the alkali halides, including potassium fluoride, potassium chloride, potassium bromide, potassium iodide, sodium fluoride, and other combinations of sodium, caesium, rubidium, or lithium ions with fluoride, bromide, chloride or iodide ions. Many other types of ionic crystals are known..
Hall-Heroult process - alumina, Al2O3 is dissolved in a carbon-lined bath of molten cryolite, Na3AlF6. Aluminum fluoride, AlF3 is also present to reduce the melting point of the cryolite. The mixture is electrolyzed, and liquid aluminum is produced at the cathode. The carbon anode is oxidized and bubbles away as carbon dioxide. The overall chemical reaction is 2 Al2O3 + 3 C → 4 Al + 3 CO2 The liquid aluminum product is denser than the molten cryolite and sinks to the bottom of the bath, where it is periodically collected. The top and sides of the bath are covered with a crust of solid cryolite which acts as thermal insulation. Electrical resistance within the bath provides sufficient heat to keep the cryolite molten. The need of electrical power and pollution of the surroundings.
Hydrofluoric acid - Hydrofluoric acid General Name Hydrogen fluoride Chemical formula HF Appearance Colorless gas Physical properties Formula weight 20.1 amu Melting point 190 K (-83 °C) Boiling point 294 K (19.5 °C) Density 0.97 ×103 kg/m3 (liquid) Solubility miscible with water Thermochemistry ΔfH0gas ? kJ/mol ΔfH0liquid ? kJ/mol ΔfH0solid ? kJ/mol S0gas, 1 bar ? J/mol·K S0liquid, 1 bar ? J/mol·K S0solid ? J/mol·K Safety Ingestion Toxic, can be fatal. Inhalation Highly toxic, can result in pulmonary edema. Skin Causes severe burns. Absorbs through skin to cause nerve, bone and organ damage. Eyes Extremely dangerous. SI units were used where possible. Unless otherwise stated, standard conditions were used. Disclaimer and references Hydrofluoric acid is a highly corrosive solution of the chemical compound hydrogen fluoride in water. Pure hydrogen fluoride is often called anhydrous.
Fluorine - all the elements, and forms compounds with most other elements, including the noble gases xenon and radon. Even in dark, cool conditions, fluorine reacts explosively with hydrogen. In a jet of fluorine gas, glass, metals, water and other substances burn with a bright flame. It always occurs combined and has such an affinity for most elements, especially silicon, that it can neither be prepared nor should be kept in glass vessels. In aqueous solution, fluorine commonly occurs as the fluoride ion F-. Other forms are fluoro-complexes (such as [FeF4]-) or H2F+. Fluorides are compounds that combine fluoride with some positively charged rest. They often consist of ions. Applications Fluorine is used in the production of low friction plastics such as Teflon, and in halons such as Freon. Other uses: Hydrofluoric acid.
Fluorescence - the absorbed photon is in the ultraviolet, and the emitted light (luminescence) is in the visible range. Fluorescence is named after the mineral fluorspar (calcium fluoride), which exhibits this phenomenon. There are many natural and synthetic compounds that exhibit fluorescence, and they have a number of applications: Table of contents showTocToggle("show","hide") 1 Lighting 2 Biochemistry & Medicine 3 Gemmology, Mineralogy and Forensics Lighting The common fluorescent tube relies on fluorescence. Inside the glass tube is a partial vacuum and a small amount of mercury. An electric discharge in the tube causes the mercury atoms to emit light. The emitted light is in the ultraviolet range and is invisible, and also harmful to living organisms, so the tube is lined with a coating of a fluorescent material, called the phosphor, which absorbs.
Fluorite - Blue John) is a mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octohedrons and dodecahedrons are not uncommon. Table of contents showTocToggle("show","hide") 1 Occurrence 1.1 Blue John 2 Uses 3 Details Occurrence Pig carved in fluorite, 5 cm (2 inches) long. Octahedral fluorite crystals. Fluorite may occur as a vein deposit, especially with metallic minerals, where it often forms a part of the gangue (the worthless `host-rock' in which valuable minerals occur) and may be associated with barite, quartz and calcite. It is a common mineral in deposits of pneumatolytic origin and has been noted as a primary mineral in granites and other igneous rocks. Blue John One of the most famous of the older localities of fluorite is Derbyshire, England, where under.
Fresh Fruit for Rotting Vegetables - "I Kill Children" (Biafra) "Stealing People's Mail" (Biafra) "Funland at the Beach" (Biafra) "Ill in the Head" (6025, Biafra) "Holiday in Cambodia" (Dead Kennedys) "Viva Las Vegas" (Pomus and Schuman) Personnel: 6025 - Guitar on "Ill in the Head" Oliver Dicicco - Engineer East Bay Ray - Guitar, Production Assistance Jello Biafra - Vocals Klaüs Fluoride - Bass, Vocals Ninotchka - Keyboard on Drug Me Norm - Producer Porky - Mastering Paul Roessler - Keyboards on "Drug Me" and "Stealing Peoples' Mail" Rocky Mountain Arsenal Choir - Clubhouse Scene on "Chemical Warfare" Ted - Drums.
Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb - Air Force General, Jack D. Ripper (Sterling Hayden), who plans to start a nuclear war with the Soviet Union in order to stop, he believes, a fearful Communist conspiracy to put fluoride in the water supply, thereby threatening our "precious bodily fluids". Spoiler warning: Plot discussed General Ripper is unaware that the Soviets have constructed a doomsday machine which automatically detects any nuclear attack on the Soviet Union, whereupon it destroys all life on earth by fallout. General Ripper's plan is foiled by Group Captain Lionel Mandrake (Peter Sellers), the British exchange officer who discovers the recall code. Unfortunately, one B-52 ("The Leper Colony") can't be called back and continues its mission to drop the one nuclear bomb that will set off the doomsday machine. The pilot of the B-52 rides.
Tantalum - Tantalum is used in surgical instruments and implants because it does not react with body fluids. Notable Characteristics Tantalum is gray, heavy, ductile, very hard, easily fabricated, highly resistant to corrosion by acids, and is a good conductor of heat and electricity. In fact, at temperatures below 150 °C tantalum is almost completely immune to chemical attack and can only be attacked by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulphur trioxide. The element has a melting point exceeded only by tungsten and rhenium (melting point 3290 K, boiling point 5731 K). Applications The major use for tantalum, as tantalum metal powder, is in the production of electronic components, mainly tantalum capacitors. Major end uses for tantalum capacitors include portable telephones, pagers, personal computers, and automotive electronics. Tantalum.
1945 - Yokohama. September 8 - US troops occupy southern Korea, Russians occupy the north. This arrangement proves to be the beginning of a divided Korea. September 8 - Hideki Tojo, Japanese prime minister during most of World War II, attempts suicide to avoid facing a war crimes tribunal. September 20 - Mohandas Gandhi and Jawaharlal Nehru demand that British troops leave India October 10 - Russian code clerk Igor Gouzenko defects to Canada. He helps the West gain an understanding of Soviet spy rings in North America. October 15 - World War II: Former premier of Vichy France, Pierre Laval, is executed by firing squad for treason. October 17 - Colonel Juan Peron stages a coup d'etat, becoming ruler of Argentina. October 18 - The first German war crimes trial begins in.
Actinium - it has no significant industrial applications. Actinium-225 is used in medicine to produce Bi-213 in a reusable generator or can be used alone as an agent for radio-immunotherapy. History Actinium was discovered in 1899 by André-Louis Debierne, a French chemist, who separated it from pitchblende. Friedrich Otto Giesel independently discovered actinium in 1902. The chemical behavior of actinium is similar to that of the rare earth lanthanum. The word actinium comes from the Greek aktis, aktinos, meaning beam or ray. Occurrence Actinium is found in trace amounts in uranium ore, but more commonly is made in milligram amounts by the neutron irradiation of 226-Ra in a nuclear reactor. Actinium metal has been prepared by the reduction of actinium fluoride with lithium vapor at about 1100 to 1300-degrees C. Compounds Isotopes Naturally.
Yttrium - and imparts shock resistance and low expansion characteristics to glass. History Yttrium (Ytterby, a Swedish village near Vauxholm) was discovered by Johann Gadolin in 1794 and isolated by Friedrich Wohler in 1828 as an impure extract of yttria through the reduction of yttrium anhydrous chloride (YCl3) with potassium. Yttria (Y2O3) is the oxide of yttruim and was discovered by Johan Gadolin in 1794 in a gadolinite mineral from Ytterby. In 1843 Carl Mosander was able to show that yttira could be divided into the oxides (or earths) of three different elements. "Yttria" was the name used for the most basic one and the others were named erbia and terbia. A quarry is located near the village of Ytterby that yielded many unusual minerals that contained rare earths and other elements. The.
Ammonia - although it is probably chiefly composed of a solution of ammonia in water. It does not support combustion, and it does not burn readily unless mixed with oxygen, when it burns with a pale yellowish-green flame. However it can form an explosive mixture with air. Salts One of the most characteristic properties of ammonia is its power of combining directly with acids to form salts; thus with hydrochloric acid it forms ammonium chloride (sal-ammoniac); with nitric acid, ammonium nitrate, etc. It is to be noted that H. B. Baker (''Journal of Chem. Soc.'', 1894, lxv. p. 612) has shown that perfectly dry ammonia will not combine with perfectly dry hydrochloric acid, moisture being necessary to bring about the reaction. The salts produced by the action of ammonia on acids are known.
Anatase - sandstones, clays, and slates, from which they may be separated by washing away the lighter constituents of the powdered rock. Crystals of the second type have numerous pyramidal faces developed, and they are usually flatter or sometimes prismatic in habit; the colour is honey-yellow to brown. Such crystals closely resemble xenotine in appearance and, indeed, were for a long time supposed to belong to this species, the special name wiserine being applied to them. They occur attached to the walls of crevices in the gneisses of the Alps, the Binnenthal near Brieg in canton Valais, Switzerland, being a well-known locality. When strongly heated, anatase is converted into rutile, changing in specific gravity to 4.1; naturally occurring pseudomorphs of rutile after anatase are also known. Crystals of anatase have been artificially prepared.
Anticoagulant - it...? Anticoagulants outside the body Laboratory instruments, test tubes, blood transfusion bags, and medical and surgical equipment will get clogged up and become unoperational if blood is allowed to clot. Chemicals can be added to stop blood clotting. Apart from heparin, most of these chemicals work by binding calcium ions, preventing the coagulation proteins from using them. EDTA - denoted by mauve or purple caps on vacutainers and test tubes. This chemical strongly and irreversably binds calcium. It is in a powdered form. Citrate - this usually is in blue vacutainers. It is in liquid form in the tube and is used for coagulation tests, as well as in blood transfusion bags. It gets rid of the calcium, but no as strongly as EDTA. Correct proportion of this anticoagulant to blood.
Apatite - and used by biological systems. Hydroxyapatite is the major component of tooth enamel, and a large component of bone material. Fluorapatite is slightly stronger than hydroxyapatite; thus, fluoridated water, which will allow exchange in the teeth of hydroxyl ions for fluoride ions, slightly strengthens the teeth. Fission tracks in apatite are commonly used to estimate the thermal history of sediments in sedimentary basins. See also: list of minerals, thermal history modelling.\n.
Bastnasite - the mineral bastnasite is one of a family of three carbonate-fluoride minerals. There is bastnasite-(Ce) with a formula of (Ce, La)CO3F. There is bastnasite-(La) with a formula of (La, Ce)CO3F. There is also bastnasite-(Y) with a formula of (Y, Ce)CO3F. Most bastnasite is bastnasite-(Ce), and cerium is by far the most common of the rare earths in this class of minerals. Bastnasite and the phosphate mineral monazite are the two largest sources of cerium. The hardness of bastnasite ranges from 4 to 4.5. The specific gravity ranges from 4.7 to 5.0, which is above average for a mineral. See also: List of minerals.
