Pyridine
Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one methine group (=CH−) replaced by a nitrogen atom. The pyridine ring occurs in many important compounds, including azines and the vitamins niacin and pyridoxine. Pyridine
Pyridine was discovered in 1849 by the Scottish chemist Thomas Anderson as one of the constituents of bone oil. Two years later, Anderson isolated pure pyridine through fractional distillation of the oil. It is a colorless, highly flammable, weakly alkaline, water-soluble liquid with a distinctive, unpleasant fish-like smell. Pyridine
Pyridine is used as a precursor to agrochemicals and pharmaceuticals and is also an important solvent and reagent. Pyridine
Pyridine is added to ethanol to make it unsuitable for drinking (see denatured alcohol)
[...More...]
Wikipedia
Yahoo
Ultraviolet–visible spectroscopy
Ultraviolet–visible spectroscopy or ultraviolet-visible spectrophotometry (UV-Vis or UV/Vis) refers to absorption spectroscopy or reflectance spectroscopy in the ultraviolet-visible spectral region. This means it uses light in the visible and adjacent ranges. The absorption or reflectance in the visible range directly affects the perceived color of the chemicals involved. In this region of the electromagnetic spectrum, atoms and molecules undergo electronic transitions
[...More...]
Wikipedia
Yahoo
R36 or R-36 may refer to: R36 (airship), the first British civil registered airship R-36 (missile), a family of intercontinental ballistic missiles and space launch vehicles designed by the Soviet Union during the Cold War R36 (New York City Subway car)
R36 (New York City Subway car) or
[...More...]
Wikipedia
Yahoo
In chemical nomenclature, a preferred IUPAC
IUPAC name (PIN) is a unique name, assigned to a chemical substance and preferred among the possible names generated by IUPAC
IUPAC nomenclature. The "preferred IUPAC nomenclature" provides a set of rules for choosing between multiple possibilities in situations where it is important to decide on a unique name. It is intended for use in legal and regulatory situations.[1] Currently, preferred IUPAC
IUPAC names are written only for part of the organic compounds (see below)
[...More...]
Wikipedia
Yahoo
A safety data sheet (SDS),[1] material safety data sheet (MSDS), or product safety data sheet (PSDS) is an important component of product stewardship, occupational safety and health, and spill-handling procedures. SDS formats can vary from source to source within a country depending on national requirements. SDSs are a widely used system for cataloging information on chemicals, chemical compounds, and chemical mixtures. SDS information may include instructions for the safe use and potential hazards associated with a particular material or product. The SDS should be available for reference in the area where the chemicals are being stored or in use. There is also a duty to properly label substances on the basis of physico-chemical, health or environmental risk
[...More...]
Wikipedia
Yahoo
The Dangerous Substances Directive[1] (as amended) was one of the main European Union
European Union laws concerning chemical safety, until its full replacement by the new regulation CLP regulation (2008), starting in 2016. It was made under Article 100 (Art. 94 in a consolidated version)[2] of the Treaty of Rome
[...More...]
Wikipedia
Yahoo
R-phrases (short for Risk Phrases) are defined in Annex III of European Union
European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations
[...More...]
Wikipedia
Yahoo
R20 may refer to:R20: Harmful by inhalation, a risk phrase in chemistry USS R-20 (SS-97), a 1918 submarine of the United States Navy Chloroform Renault 20 R20 series, preferred numbers in industrial design R20, a name for a type of battery, see list of battery sizes R20, a size of light bulb reflector, equivalent to R63, see Incandescent light bulb shapes R20, a Samsung Sens
Sams
[...More...]
Wikipedia
Yahoo
R21, R-21 or R.21 may refer to:In military HMAS Melbourne (R21), a 1945 Australian Royal Navy ship of the Majestic class of light aircraft carrier R-21 (missile), a submarine-launched ballistic missile developed and deployed by the Soviet Union USS R-21 (SS-98), a 1918 R-class coastal and harbor defense submarine of the United States NavyIn transportation R21 (New York City Subway car) R21 road (Senegal) R21 road (South Africa) Renault 21, a large family car produced between 1986 and 1994In science and academia R21: Harmful in contact with skin
[...More...]
Wikipedia
Yahoo
R22 may refer to: R22 (band), a metalcore/hard rock band from Brooklyn, New York R22 (New York City Subway car) R22 road (Belgium), a (part of) inner ringway around Brussels R22 road (South Africa) R22 road (
[...More...]
Wikipedia
Yahoo
R34 may refer to:R34 (airship) - British airship that made the first East-West crossing of the Atlantic by air Rule 34 (other) R34 (New York City Subway car) R34 road (South Africa) R34: Causes burns, a risk phrase a model of the Nissan SkylineThis disambiguation page lists articles associated with the same title formed as a letter-number combination. If an internal link led you here, you may wish to change the link to point directly to the
[...More...]
Wikipedia
Yahoo
The R38 class (also known as the A class) of rigid airships was designed for Britain's Royal Navy
Royal Navy during the final months of the First World War, intended for long-range patrol duties over the North Sea. Four similar airships were originally ordered by the Admiralty, but orders for three of these (R39, R40 and R41) were cancelled after the armistice with Germany and R.38, the lead ship of the class, was sold to the United States Navy
United States Navy in October 1919 before completion. On 23 August 1921, R-38 was destroyed by a structural failure while in flight over the city of Hull
[...More...]
Wikipedia
Yahoo
In optics, the refractive index or index of refraction of a material is a dimensionless number that describes how light propagates through that medium. It is defined as n = c v , displaystyle n= frac c v , where c is the speed of light in vacuum and v is the phase velocity of light in the medium. For example, the refractive index of water is 1.333, meaning that light travels 1.333 times faster in vacuum than in the water. Refraction
Refraction of a light rayThe refractive index determines how much the path of light is bent, or refracted, when entering a material. This is the first documented use of refractive indices and is described by Snell's law
Snell's law of refraction, n1 sinθ1 = n2 sinθ2, where θ1 and θ2 are the angles of incidence and refraction, respectively, of a ray crossing the interface between two media with refractive indices n1 and n2
[...More...]
Wikipedia
Yahoo
"NFPA 704: Standard System for the Identification of the Hazards of Materials for Emergency Response" is a standard maintained by the U.S.-based National Fire Protection Association. First "tentatively adopted as a guide" in 1960,[1] and revised several times since then, it defines the colloquial "fire diamond" or "safety square" used by emergency personnel to quickly and easily identify the risks posed by hazardous materials. This helps determine what, if any, special equipment should be used, procedures followed, or precautions taken during the initial stages of an emergency response.Contents1 Codes 2 See also 3 References 4 External linksCodes[edit]The four divisions are typically color-coded with red indicating flammability, blue indicating level of health hazard, yellow for chemical reactivity, and white containing codes for special hazards. Each of health, flammability and reactivity is rated on a scale from 0 (no hazard) to 4 (severe risk)
[...More...]
Wikipedia
Yahoo
The flash point of a volatile material is the lowest temperature at which vapours of the material will ignite, when given an ignition source. The flash point may sometimes be confused with the autoignition temperature, which is the temperature at which the vapor ignites spontaneously without an ignition source. The fire point is the lowest temperature at which vapors of the material will keep burning after being ignited and the ignition source removed
[...More...]
Wikipedia
Yahoo
The threshold limit value (TLV) of a chemical substance is believed to be a level to which a worker can be exposed day after day for a working lifetime without adverse effects. Strictly speaking, TLV is a reserved term of the American Conference of Governmental Industrial Hygienists (ACGIH). TLVs issued by the ACGIH are the most widely accepted occupational exposure limits both in the United States and most other countries.[1] However, it is sometimes loosely used to refer to other similar concepts used in occupational health and toxicology, such as acceptable daily intake (ADI) and tolerable daily intake (TDI). Concepts such as TLV, ADI, and TDI can be compared to the no-observed-adverse-effect level (NOAEL) in animal testing, but whereas a NOAEL can be established experimentally during a short period, TLV, ADI, and TDI apply to human beings over a lifetime and thus are harder to test empirically and are usually set at lower levels
[...More...]
Wikipedia
Yahoo