Phallolysin is a toxic haemolysin that has been isolated from the death cap Amanita phalloides.
This medical article is a stub. You can help Wikipedia by expanding it.
Retrieved from “http://en.wikipedia.org/wiki/Phallolysin”
Categories: Mycotoxins | Medicine stubs
For other uses, see Functional group (disambiguation).
Benzyl acetate has an ester functional group (in red), an acetyl moiety (circled with green) and an benzyl alcohol moiety (circled with orange).
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction(s) regardless of the size of the molecule it is a part of. However, its relative reactivity can be modified by nearby functional groups.
The word moiety is often used synonymously to “functional group”, but according to the IUPAC definition, a moiety is a half of a molecule including substructures of functional groups. For example, an ester is divided into an alcohol and an acyl moiety, but has an ester functional group. The use of the word “moiety” to mean a functional group in the chemistry sense is actually fairly recent. While it has commonly been used in the archeology field to mean the half of a tribal family, it wasn’t until a chance encounter between Elizabeth Bollwerk, an archeology graduate student, and a drug research scientist that the term made the cross-over.
Combining the names of functional groups with the names of the parent alkanes generates a powerful systematic nomenclature for naming organic compounds.
The non-hydrogen atoms of functional groups are always associated with each other and with the rest of the molecule by covalent bonds. When the group of atoms is associated with the rest of the molecule primarily by ionic forces, the group is referred to more properly as a polyatomic ion or complex ion. And all of these are called radicals, by a meaning of the term radical that predates the free radical.
The first carbon atom after the carbon that attaches to the functional group is called the alpha carbon; the second, beta carbon, the third, gamma carbon, etc. If there is another functional group at a carbon, it may be named with the Greek letter, e.g. the gamma-amine in gamma-aminobutanoic acid is on the third carbon of the carbon chain attached to the carboxylic acid group.
Functional groups are attached to the carbon backbone of organic molecules. They determine the characteristics and chemical reactivity of molecules. Functional groups are far less stable than the carbon backbone and are likely to participate in chemical reactions.
Contents
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Table of common functional groups
The following is a list of common functional groups. In the formulas, the symbols R and R’ usually denote an attached hydrogen, or a hydrocarbon side chain of any length, but may sometimes refer to any group of atoms.
Hydrocarbons
Functional groups that vary based upon the number and order of π bonds impart different chemistry. Each listing below contains C-H bonds, but each one differs in type (and scope) of reactivity.
Chemical class
Group
Formula
Structural Formula
Prefix
Suffix
Example
Alkane
Alkyl
RH
alkyl-
-ane
Ethane
Alkene
Alkenyl
R2C=CR2
alkenyl-
-ene
Ethylene
(Ethene)
Alkyne
Alkynyl
RC≡CR’
alkynyl-
-yne
Acetylene
(Ethyne)
Benzene derivative
Phenyl
RC6H5
RPh
phenyl-
-benzene
Cumene
(2-phenylpropane)
Toluene derivative
Benzyl
RCH2C6H5
RBn
benzyl-
1-(substituent)toluene
Benzyl bromide
(1-Bromotoluene)
There are also a large number of branched or ring alkanes that have specific names, e.g. tert-butyl, bornyl, cyclohexyl, etc.
Groups containing halogens
Haloalkanes are a class of molecule that is defined by a carbon-halogen bond. This bond can be relatively weak (in the case of an iodoalkane) or quite stable (as in the case of a fluoroalkane). In general, with the exception of fluorinated compounds, haloalkanes readily undergo nucleophilic substitution reactions or elimination reactions. The substitution on the carbon, the acidity of an adjacent proton, the solvent conditions, etc. all can influence the outcome of the reactivity.
Chemical class
Group
Formula
Structural Formula
Prefix
Suffix
Example
haloalkane
halo
RX
halo-
alkyl halide
Chloroethane
(Ethyl chloride)
fluoroalkane
fluoro
RF
fluoro-
alkyl fluoride
Fluoromethane
(Methyl fluoride)
chloroalkane
chloro
RCl
chloro-
alkyl chloride
Chloromethane
(Methyl chloride)
bromoalkane
bromo
RBr
bromo-
alkyl bromide
Bromomethane
(Methyl bromide)
iodoalkane
iodo
RI
iodo-
alkyl iodide
Iodomethane
(Methyl iodide)
Groups containing oxygen
Compounds that contain C-O bonds each possess differing reactivity based upon the location and hybridization of the C-O bond, owing to the electron-withdrawing effect of sp² hybridized oxygen and the donating effects of sp³ hybridized oxygen.
Chemical class
Group
Formula
Structural Formula
Prefix
Suffix
Example
Acyl halide
Haloformyl
RCOX
haloformyl-
-oyl halide
Acetyl chloride
(Ethanoyl chloride)
Alcohol
Hydroxyl
ROH
hydroxy-
-ol
Methanol
Ketone
Carbonyl
RCOR’
keto-, oxo-
-one
Methyl ethyl ketone
(Butanone)
Aldehyde
Aldehyde
RCHO
aldo-
-al
Acetaldehyde
(Ethanal)
Carbonate
Carbonate ester
ROCOOR
alkyl carbonate
carboxy-
-oate
Sodium acetate
(Sodium ethanoate)
Carboxylic acid
Carboxyl
RCOOH
carboxy-
-oic acid
Acetic acid
(Ethanoic acid)
Ether
Ether
ROR’
alkoxy-
alkyl alkyl ether
Diethyl ether
(Ethoxyethane)
alkyl alkanoate
Ethyl butyrate
(Ethyl butanoate)
Hydroperoxide
Hydroperoxy
ROOH
hydroperoxy-
alkyl hydroperoxide
Methyl ethyl ketone peroxide
Peroxide
Peroxy
ROOR
peroxy-
alkyl peroxide
Di-tert-butyl peroxide
Groups containing nitrogen
Compounds that contain Nitrogen in this category may contain C-O bonds, such as in the case of amides.
Chemical class
Group
Formula
Structural Formula
Prefix
Suffix
Example
Amide
Carboxamide
RCONR2
carboxamido-
-amide
Acetamide
(Ethanamide)
Amines
Primary amine
RNH2
amino-
-amine
Methylamine
(Methanamine)
Secondary amine
R2NH
amino-
-amine
Dimethylamine
Tertiary amine
R3N
amino-
-amine
Trimethylamine
4° ammonium ion
R4N+
ammonio-
-ammonium
Choline
Imine
Primary ketimine
RC(=NH)R’
imino-
-imine
Secondary ketimine
RC(=NR)R’
imino-
-imine
Primary aldimine
RC(=NH)H
imino-
-imine
Secondary aldimine
RC(=NR’)H
imino-
-imine
Imide
Imide
RC(=O)NC(=O)R’
imido-
-imide
Azide
Azide
RN3
azido-
alkyl azide
Phenyl azide
(Azidobenzene)
Azo compound
Azo
(Diimide)
RN2R’
azo-
-diazene
Methyl orange
(p-dimethylamino-azobenzenesulfonic acid)
Cyanates
Cyanate
ROCN
cyanato-
alkyl cyanate
Isocyanide
RNC
isocyano-
alkyl isocyanide
Isocyanates
Isocyanate
RNCO
isocyanato-
alkyl isocyanate
Methyl isocyanate
Isothiocyanate
RNCS
isothiocyanato-
alkyl isothiocyanate
Allyl isothiocyanate
Nitrate
Nitrate
RONO2
nitrooxy-, nitroxy-
alkyl nitrate
Amyl nitrate
(1-nitrooxypentane)
alkanenitrile
alkyl cyanide
Nitrite
Nitrosooxy
RONO
nitrosooxy-
alkyl nitrite
Isoamyl nitrite
(3-methyl-1-nitrosooxybutane)
Nitro compound
Nitro
RNO2
nitro-
Nitromethane
Nitroso compound
Nitroso
RNO
nitroso-
Nitrosobenzene
Pyridine derivative
Pyridyl
RC5H4N
4-pyridyl
(pyridin-4-yl)
3-pyridyl
(pyridin-3-yl)
2-pyridyl
(pyridin-2-yl)
Groups containing phosphorus and sulfur
Compounds that contain sulfur and phosphorus exhibit unique chemistry due to their ability to form more bonds than nitrogen and oxygen, their lighter analogues on the periodic table.
Chemical class
Group
Formula
Structural Formula
Prefix
Suffix
Example
Phosphine
Phosphino
R3P
phosphino-
-phosphane
Methylpropylphosphane
Phosphodiester
Phosphate
HOPO(OR)2
phosphoric acid di(substituent) ester
di(substituent) hydrogenphosphate
DNA
Phosphonic acid
Phosphono
RP(=O)(OH)2
phosphono-
substituent phosphonic acid
Benzylphosphonic acid
Phosphate
Phosphate
ROP(=O)(OH)2
phospho-
Sulfide or thioether
di(substituent) sulfide
Dimethyl sulfide
Sulfone
Sulfonyl
RSO2R’
sulfonyl-
di(substituent) sulfone
Dimethyl sulfone
(Methylsulfonylmethane)
Sulfonic acid
Sulfo
RSO3H
sulfo-
substituent sulfonic acid
Benzenesulfonic acid
Sulfoxide
Sulfinyl
RSOR’
sulfinyl-
di(substituent) sulfoxide
Diphenyl sulfoxide
Thiol
Sulfhydryl
RSH
mercapto-, sulfanyl-
-thiol
Ethanethiol
(Ethyl mercaptan)
Thiocyanate
Thiocyanate
RSCN
thiocyanato-
alkyl thiocyanate
alkyl alkyl disulfide
Diphenyl disulfide
1,2-diphenyldisulfane
Other
References
External links
Functional groups
Chemical class: Alcohol • Aldehyde • Alkane • Alkene • Alkyne • Amide • Amine • Azo compound • Benzene derivative • Carboxylic acid • Cyanate • Disulfide • Ester • Ether • Haloalkane • Hydrazone • Imine • Isocyanide • Isocyanate • Ketone • Oxime • Nitrile • Nitro compound • Nitroso compound • Peroxide • Phosphoric acid • Pyridine derivative • Sulfone • Sulfonic acid • Sulfoxide • Thioester • Thioether • Thiol
Concepts in organic chemistry
Aromaticity, Covalent bonding, Functional groups, Nomenclature, Organic compounds, Organic reactions, Organic synthesis, Publications, Spectroscopy, Stereochemistry, List of organic compounds
Retrieved from “http://en.wikipedia.org/wiki/Functional_group”
Categories: Functional groups | Organic compounds
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WikiProject Pharmacology or the Pharmacology Portal may be able to help recruit one.
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Benzethonium chloride
Systematic (IUPAC) name
benzyl-dimethyl-[2-[2-[4-
(2,4,4-trimethylpentan-2-yl)phenoxy]ethoxy]ethyl]
azanium chloride
Identifiers
CAS number
121-54-0
ATC code
D08AJ58
PubChem
8478
Chemical data
Mol. mass
448.081 g/mol
SMILES
eMolecules & PubChem
Pharmacokinetic data
Bioavailability
?
Metabolism
?
Half life
?
Excretion
?
Therapeutic considerations
Pregnancy cat.
?
Legal status
OTC(US)
Routes
Topical
Benzethonium chloride is a synthetic quaternary ammonium, surfactant, antiseptic, and anti-infective compound used as a topical antimicrobial agent in cosmetics and personal care products like anti-itch ointments and antibacterial moist towelettes and wipes. Benzothonium chloride is also used is the food industry as a disinfectant and preservative.
It is available under trade names salanine, BZT, diapp, quatrachlor, polymine d, phemithyn, antiseptol, disilyn, phermerol, and others.
Retrieved from “http://en.wikipedia.org/wiki/Benzethonium_chloride”
Categories: Chlorides | Quaternary ammonium compounds | Surfactants | Antiseptics | Disinfectants | PreservativesHidden categories: Pharmacology articles needing expert attention | Articles needing expert attention | Pages needing expert attention
In molecular biology, an inducer is a molecule that starts gene expression.
For a gene to be expressed, its DNA sequence must be copied (in a process known as transcription) to make a smaller, mobile molecule called messenger RNA (mRNA), which carries the instructions for making a protein to the site where the protein is manufactured (in a process known as translation). Many different types of proteins can effect the level of gene expression by promoting or preventing transcription. In prokaryotes (such as bacteria), these proteins often act on a portion of DNA known as the operator at the beginning of the gene. The operator is where RNA polymerase, the enzyme which copies the genetic sequence and synthesizes the mRNA, attaches to the DNA strand.
Inducers function by disabling repressor proteins. Repressor proteins bind to the DNA strand and prevent RNA polymerase from being able to attach to the DNA and synthesize mRNA. Inducers bind to repressors, causing them to change shape and preventing them from binding to DNA. Therefore, they allow transcription, and thus gene expression, to take place. Some inducers are modulated by activators, which have the opposite effect on gene expression as repressors. Inducers bind to activator proteins, allowing them to bind to the DNA strand where they promote RNA transcription.
Ligands that bind to deactivate activator proteins are not technically classified as inducers, since they have the effect of preventing transcription.
External links
Look up Inducer in
Wiktionary, the free dictionary.
This biochemistry article is a stub. You can help Wikipedia by expanding it.
Retrieved from “http://en.wikipedia.org/wiki/Inducer”
Categories: Biochemistry stubs | Gene expression | Organic compounds
Calcium hydride
Image:Calcium hydride.jpg
IUPAC name
Calcium(II) hydride
Other names
Calcium hydride
Calcium dihydride
Identifiers
CAS number
Properties
Molecular formula
CaH2
Molar mass
42.094 g/mol
Appearance
gray (pure: colourless)
Density
1.90 g/cm3, solid
Melting point
816 °C
Solubility in water
reacts violently
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references
Calcium hydride is the chemical compound with the formula CaH2. This grey powder (white if pure, which is rare) reacts vigorously with water liberating hydrogen gas. CaH2 is thus used as a drying agent, i.e. a desiccant.
CaH2 is a saline hydride, meaning that its structure is salt-like. The alkali metals and the alkaline earth metals all form saline hydrides. A well-known example is sodium hydride, which crystallizes in the NaCl motif. These species are insoluble in all solvents with which they do not react because they have extended structures. CaH2 crystallizes in the PbCl2 motif.
Use as a desiccant
The reaction of CaH2 with water can be represented as follows:
CaH2 + 2 H2O → Ca(OH)2 + 2 H2
The two hydrolysis products, H2, a gas, and Ca(OH)2, a solid, are readily separated from the solvent by distillation, filtration, or decantation.
As calcium hydride is a relatively mild desiccant, it is safe compared with more reactive agents such as sodium metal or sodium-potassium alloy. Calcium hydride is widely used as a desiccant for basic solvents such as amines and pyridine. It is also used to pre-dry solvents prior to the use of a more reactive desiccant.
Drawbacks
Although CaH2 is indeed convenient and often the drying agent of choice, it has a few drawbacks:
References
This inorganic compound-related article is a stub. You can help Wikipedia by expanding it.
Retrieved from “http://en.wikipedia.org/wiki/Calcium_hydride”
Categories: Metal hydrides | Calcium compounds | Desiccants | Inorganic compound stubs
Anthoxanthins are a type of flavonoid pigments in plants. Anthoxanthins are water-soluble pigments which range in color from white or colorless to a creamy to yellow, often on petals of flowers. These pigments are generally whiter in an acid medium and yellowed in an alkaline medium. They are very susceptible to color changes with minerals and metal ions, similar to anthocyanins. As with all flavonoids, they exhibit antioxidant properties, and are important in nutrition, and are sometimes used as food additives. Darkening with iron is particularly prominent in food products. They are considered to have more variety than anthocyanins. Some examples are quercitin.
Types of Plant Pigments
Flavonoids
Anthocyanins • Anthocyanidins • Anthoxanthins • Proanthocyanidins • Tannins
Betalains
Betacyanins • Betaxanthins
Carotenoids
Xanthophylls • Carotenes • Retinoids
Other
Chlorophyll • Allophycocyanin • Phycocyanin • Phycoerythrin • Phycoerythrocyanin • Quinones • Xanthones
Types of Flavonoids
Flavones:
Apigenin | Luteolin | Tangeritin Synthetics: Diosmin | Flavoxate
Isoflavones:
Biochanin A | Coumestrol | Daidzein | Daidzin | Formononetin | Genistein | Puerarin
Flavonols:
Fisetin | Isorhamnetin | Kaempferol | Myricetin | Pachypodol | Quercetin | Rhamnazin
Flavanones:
Eriodictyol | Hesperetin | Homoeriodictyol | Naringenin
3-Hydroxyflavanones:
Dihydrokaempferol | Dihydroquercetin
Flavan-3-ols:
Catechins | Epicatechins | Epigallocatechin
Anthocyanidins:
Cyanidin | Delphinidin | Malvidin | Pelargonidin | Peonidin | Petunidin
Misc:
List of phytochemicals and foods in which they are prominent
Major families of biochemicals
Saccharides | Carbohydrates | Glycosides | | Amino acids | Peptides | Proteins | Glycoproteins | | Lipids | Terpenes | Steroids | Carotenoids
Alkaloids | Nucleobases | Nucleic acids | | Enzyme cofactors | Flavonoids | Polyketides | Tetrapyrroles
Retrieved from “http://en.wikipedia.org/wiki/Anthoxanthin”
Categories: Pigments | PH indicators | Bioindicators | Nutrition
Orellanine
IUPAC name
Orellanine
Other names
Orellanin,
2,2-bipyridine-3,3-4,4-tetrol-1,1-dioxide,
3,3′,4,4′-Tetrahydroxy-2,2′-bipyridine-N,N’-dioxide
Identifiers
CAS number
Properties
Molecular formula
C10H8N2O6
Molar mass
252.17 g/mol
Hazards
Main hazards
Highly toxic
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references
Orellanine or Orellanin is a pyridine N-oxide and a crystalline alkaloid that is found naturally in some lifeforms, specifically certain fungi. It has been found in at least 34 types of mushrooms in the Cortinariaceae family.
Contents
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History
In Poland during the 1950s there was a small epidemic where over 100 people became ill. What caused the illness remained a mystery until 1952 when Polish physician Dr. S. Grzymała discovered that everyone suffering from the illness, which had by now claimed several lives, had eaten the mushroom Cortinarius orellanus.
In 1955 he isolated a substance from the fungus. He named it orellanine after the Latin name of the toadstool. Given orally to research animals, he produced the same reaction as in humans.
In 1973 orellanine was discovered in the toadstool Cortinarius rubellus.
Chemistry
The chemical constitution of orellanine remained unknown until the Polish chemists Antkowiak and Gessner in the last half of the 1970s discovered that it belongs to a group of compounds called bipyridines, a double ring structure where both rings are principally a pyridine ring (a heterocyclic ring with one nitrogen atom). In the most stable form of orellanine, the nitrogen atoms are positively charged.
An interesting feature of orellanine is its ability to bind aluminium ions to organic complexes.
Toxicity
Bipyridines with positively charged nitrogen atoms were already known to be poisonous before the structure of orellanine was elucidated. The herbicides paraquat and diquat are toxic not only to plants, but also to animals including humans. Bipyridines with charged nitrogen atoms confound important redox reactions in organisms, ‘stealing’ one or two electrons and sometimes bypass the electrons into other and often undesirable redox reactions. The terminal product can be peroxide or superoxide ions, the latter of which is harmful to the cells. It is likely that orellanine works in the same way, although the process from disturbed redox reactions to the serious clinical kidney damage has not been properly resolved.
In humans, a characteristic of poisoning by the nephrotoxin orellanine is the long latency; the first symptoms usually do not appear until 2-3 days after ingestion and can in some cases take as long as 3 weeks. The first symptoms of orellanine poisoning are similar to the common flu (nausea, vomiting, stomach pains, headaches, myalgia, etc), these symptoms are followed by early stages of renal failure (immense thirst, frequent urination, pain on and around the kidneys) and eventually decreased or nonexistent urine output and other symptoms of renal failure occur. If left untreated death will follow.
The lethal dose of orellanine in mice is 12 to 20 mg per kg body weight, where it must be noted that this is the dose which leads to death within two weeks. From cases of orellanine-related mushroom poisoning in humans it seems that the lethal dose for humans is considerably lower.
Treatment
Although there is no known antidote against orellanine poisoning, early hospitalization can sometimes prevent serious injury and usually prevent death. Research is ongoing. Some treatments make use of anti-oxidant therapy and corticosteroids to help victims recover from their renal failure.
References
See also
External links
Retrieved from “http://en.wikipedia.org/wiki/Orellanine”
Categories: Biomolecules | Alkaloids | Nephrology | Mycotoxins | Pyridines | Amine oxidesHidden categories: All articles with unsourced statements | Articles with unsourced statements since February 2008
Methyl red
IUPAC name
Methyl red
Identifiers
CAS number
(neutral)
(HCl salt)
(sodium salt)
SMILES
CN(C)c2ccc(/N=N/
c1ccccc1C(O)=O)cc2
Properties
Molecular formula
C15H15N3O2
Molar mass
269.299 g/mol
Melting point
179-182 °C
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references
Methyl Red (pH indicator)
below pH 4.4
above pH 6.2
4.4
↔
6.2
Methyl red, also called C.I. Acid Red 2, is an indicator dye that turns red in acidic solutions. It is an azo dye, and is a dark red crystalline powder.
Methyl red is a pH indicator; it is red in pH under 4.4, yellow in pH over 6.2, and orange in between.
Murexide and methyl red are investigated as promising enhancers of sonochemical destruction of chlorinated hydrocarbon pollutants.
Methyl red is classed by the IARC in group 3 - unclassified as to carcinogenic potential in humans. Its risk phrases are R20 R21 R22 R36 R37 R38 R40.
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Methyl red test
In microbiology, methyl red is used in the Methyl Red (MR) Test, used to identify bacteria producing stable acids by mechanisms of mixed acid fermentation of glucose (cf. Voges-Proskauer (VP) test).
The methyl red test is the “M” portion of the four IMViC tests used to characterize enteric bacteria. The methyl red test is used to identify enteric bacteria based on their pattern of glucose metabolism. All enterics initially produce pyruvic acid from glucose metabolism. Some enteric subsequently use the mixed acid pathway to metabolize pyruvic acid to other acids, such as lactic, acetic, and formic acids. These bacteria are called methyl-red positive and include Escherichia coli and Proteus vulgaris. Other enterics subsequently use the buytylene glycol pathway to metabolize pyruvic acid to neutral end-products. These bacteria are called methyl-red-negative and include Serratia marcescens and Enterobacter aerogenes.
Process
An isolate is inoculated into a tube with a sterile transfer loop. The tube is incubated at 35*C for 2-5 days. After incubation, 2.5ml of the medium is transferred to another tube. Five drops of the pH indicator methyl red is added to this tube. The tube is gently rolled between the palms of the hands to disperse the methyl red.
Expected results
Enterics that subsequently metabolize pyruvic acid to other acids lower the pH of the medium to 4.2. At this pH, methyl red turns red. A red color represents a positive test. Enterics that subsequently metabolize pyruvic acid to neutral end-products lower the pH of the medium to only 6.0. At this pH, methyl red is yellow. A yellow color represents a negative test.
See also
References
External links
Retrieved from “http://en.wikipedia.org/wiki/Methyl_red”
Categories: PH indicators | IARC Group 3 carcinogens | Azo dyesHidden categories: All articles with dead external links | Articles with dead external links since March 2008
For sodium in the diet, see Salt.
11
neon ← sodium → magnesium
Li
↑
Na
↓
K
Periodic table - Extended periodic table
General
Name, symbol, number
sodium, Na, 11
Chemical series
alkali metals
Group, period, block
1, 3, s
Standard atomic weight
22.98976928(2) g·mol−1
Electron configuration
3s1
Electrons per shell
1s22s22p63s1
Physical properties
Phase
solid
Density (near r.t.)
0.968 g·cm−3
Liquid density at m.p.
0.927 g·cm−3
Melting point
370.87 K
(97.72 °C, 207.9 °F)
Boiling point
1156 K
(883 °C, 1621 °F)
Critical point
(extrapolated)
2573 K, 35 MPa
Heat of fusion
2.60 kJ·mol−1
Heat of vaporization
97.42 kJ·mol−1
Specific heat capacity
(25 °C) 28.230 J·mol−1·K−1
Vapor pressure
P/Pa
1
10
100
1 k
10 k
100 k
at T/K
554
617
697
802
946
1153
Atomic properties
Crystal structure
cubic body centered
Oxidation states
1
(strongly basic oxide)
Electronegativity
0.93 (Pauling scale)
Ionization energies
(more)
1st: 495.8 kJ·mol−1
2nd: 4562 kJ·mol−1
3rd: 6910.3 kJ·mol−1
Atomic radius
180 pm
Atomic radius (calc.)
190 pm
Covalent radius
154 pm
Van der Waals radius
227 pm
Miscellaneous
Magnetic ordering
paramagnetic
Electrical resistivity
(20 °C) 47.7 nΩ·m
Thermal conductivity
(300 K) 142 W·m−1·K−1
Thermal expansion
(25 °C) 71 µm·m−1·K−1
Speed of sound (thin rod)
(20 °C) 3200 m/s
Young’s modulus
10 GPa
Shear modulus
3.3 GPa
Bulk modulus
6.3 GPa
Mohs hardness
0.5
Brinell hardness
0.69 MPa
CAS registry number
7440-23-5
Selected isotopes
Main article: Isotopes of sodium
iso
NA
half-life
DM
DE (MeV)
DP
22Na
syn
2.602 y
β+→γ
0.5454
22Ne*
1.27453(2)
22Ne
ε→γ
-
22Ne*
1.27453(2)
22Ne
β+
1.8200
22Ne
23Na
100%
23Na is stable with 12 neutrons
References
Sodium (pronounced /ˈsoʊdiəm/) is a chemical element which has the symbol Na (Latin: natrium), atomic number 11, atomic mass 22.9898 g/mol, common oxidation number +1. Sodium is a soft, silvery white, highly reactive element and is a member of the alkali metals within “group 1″ (formerly known as ‘group IA’). It has only one stable isotope, 23Na. Sodium was first isolated by Sir Humphry Davy in 1807 by passing an electric current through molten sodium hydroxide. Sodium quickly oxidizes in air and is violently reactive with water, so it must be stored in an inert medium, such as kerosene. Sodium is present in great quantities in the earth’s oceans as sodium chloride (common salt). It is also a component of many minerals, and it is an essential element for animal life. As such, it is classified as a “dietary inorganic macro-mineral.”
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Characteristics
At room temperature, sodium metal is so soft that it can be easily cut with a knife. In air, the bright silvery luster of freshly exposed sodium will rapidly tarnish. The density of alkali metals generally increases with increasing atomic number, but sodium is denser than potassium.
Chemical properties
Compared with other alkali metals, sodium is generally less reactive than potassium and more reactive than lithium, in accordance with “periodic law”: for example, their reaction in water, chlorine gas, etc.; the reactivity of their nitrates, chlorates, perchlorates, etc.
Sodium reacts exothermically with water: small pea-sized pieces will bounce across the surface of the water until they are consumed by it, whereas large pieces will explode. While sodium reacts with water at room temperature, the sodium piece melts with the heat of the reaction to form a sphere, if the reacting sodium piece is large enough. The reaction with water produces very caustic sodium hydroxide (lye) and highly flammable hydrogen gas. These are extreme hazards (see Precautions section below). When burned in air, sodium forms sodium peroxide Na2O2, or with limited oxygen, the oxide Na2O (unlike lithium, the nitride is not formed). If burned in oxygen under pressure, sodium superoxide NaO2 will be produced.
In chemistry, most sodium compounds are considered soluble but nature provides examples of many insoluble sodium compounds such as the feldspars. There are other insoluble sodium salts such as sodium bismuthate NaBiO3, sodium octamolybdate Na2Mo8O25• 4H2O, sodium thioplatinate Na4Pt3S6, sodium uranate Na2UO4. Sodium meta-antimonate’s 2NaSbO3•7H2O solubility is 0.3g/L as is the pyro form Na2H2Sb2O7• H2O of this salt. Sodium metaphosphate NaPO3 has a soluble and an insoluble form.
Isotopes
Main article: Isotopes of sodium
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There are thirteen isotopes of sodium that have been recognized. The only stable isotope is 23Na. Sodium has two radioactive cosmogenic isotopes (22Na, half-life = 2.605 years; and 24Na, half-life ≈ 15 hours).
Acute neutron radiation exposure (e.g., from a nuclear criticality accident) converts some of the stable 23Na in human blood plasma to 24Na. By measuring the concentration of this isotope, the neutron radiation dosage to the victim can be computed.
History
The flame test for sodium displays a brilliantly bright yellow emission due to the so called “sodium D-lines” at 588.9950 and 589.5924 nanometers.
Salt has been an important commodity in human activities, as testified by the English word salary, referring to salarium, the wafers of salt sometimes given to Roman soldiers along with their other wages.
In medieval Europe a compound of sodium with the Latin name of sodanum was used as a headache remedy. The name sodium probably originates from the Arabic word suda meaning headache as the headache curing properties of sodium carbonate or soda were well known in early times.
Sodium’s chemical abbreviation Na was first published by Jöns Jakob Berzelius in his system of atomic symbols (Thomas Thomson’s Annals of Philosophy word for a natural mineral salt whose primary ingredient is hydrated sodium carbonate. Which historically had several important industrial and household uses later eclipsed by soda ash, baking soda and other sodium compounds.
Although sodium (sometimes called “soda” in English) has long been recognized in compounds, it was not isolated until 1807 by Sir Humphry Davy through the electrolysis of caustic soda.
Sodium imparts an intense yellow color to flames. As early as 1860, Kirchhoff and Bunsen noted the high sensitivity that a flame test for sodium could give. They state in Annalen der Physik und der Chemie in the paper “Chemical Analysis by Observation of Spectra”:
In a corner of our 60 cu.m. room farthest away from the apparatus, we exploded 3 mg. of sodium chlorate with milk sugar while observing the nonluminous flame before the slit. After a while, it glowed a bright yellow and showed a strong sodium line that disappeared only after 10 minutes. From the weight of the sodium salt and the volume of air in the room, we easily calculate that one part by weight of air could not contain more than 1/20 millionth weight of sodium.
Spectroscopy
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A FASOR tuned to the D2A component of the sodium D line, used at the Starfire Optical Range to excite sodium atoms in the upper atmosphere.
When sodium or its compounds are introduced into a flame, they turn the flame a bright yellow color.
One notable atomic spectral line of sodium vapor is the so-called D-line, which may be observed directly as the sodium flame-test line (see Applications) and also the major light output of low-pressure sodium lamps (these produce an unnatural yellow, rather than the peach-colored glow of high pressure lamps). The D-line is one of the classified Fraunhofer lines observed in the visible spectrum of the sun’s electromagnetic radiation. Sodium vapor in the upper layers of the sun creates a dark line in the emitted spectrum of electromagnetic radiation by absorbing visible light in a band of wavelengths around 589.5 nm. This wavelength corresponds to transitions in atomic sodium in which the valence-electron transitions from a 3p to 3s electronic state. Closer examination of the visible spectrum of atomic sodium reveals that the D-line actually consists of two lines called the D1 and D2 lines at 589.6 nm and 589.0 nm, respectively. This fine structure results from a spin-orbit interaction of the valence electron in the 3p electronic state. The spin-orbit interaction couples the spin angular momentum and orbital angular momentum of a 3p electron to form two states that are respectively notated as and in the LS coupling scheme. The 3s state of the electron gives rise to a single state which is notated as 3s(2S1 / 2) in the LS coupling scheme. The D1-line results from an electronic transition between 3s(2S1 / 2) lower state and upper state. The D2-line results from an electronic transition between 3s(2S1 / 2) lower state and upper state. Even closer examination of the visible spectrum of atomic sodium would reveal that the D-line actually consists of a lot more than two lines. These lines are associated with hyperfine structure of the 3p upper states and 3s lower states. Many different transitions involving visible light near 589.5 nm may occur between the different upper and lower hyperfine levels.
A practical use for lasers which work at the sodium D-line transition (see FASOR illustration) is to create artificial laser guide stars (artificial star-like images from sodium in the upper atmosphere) which assist in the adaptive optics for large land-based visible light telescopes.
Phase behavior under pressure
Under extreme pressure, sodium departs from common melting behavior. Most materials require higher temperatures to melt under pressure than they do at normal atmospheric pressure. This is because they expand on melting due to looser molecular packing in the liquid, and thus pressure forces equilibrium in the direction of the denser solid phase.
At a pressure of 30 gigapascals (300,000 times sea level atmospheric pressure), the melting temperature of sodium begins to drop. At around 100 gigapascals, sodium will melt at near room temperature. A possible explanation for the aberrant behavior of sodium is that this element has one free electron that is pushed closer to the other 10 electrons when placed under pressure, forcing interactions that are not normally present. While under pressure, solid sodium assumes several odd crystal structures suggesting that the liquid might have unusual properties such as superconduction or superfluidity.
Occurrence
See also: Category:Sodium minerals
Owing to its high reactivity, sodium is found in nature only as a compound and never as the free element. Sodium makes up about 2.6% by weight of the Earth’s crust, making it the sixth most abundant element overall and the most abundant alkali metal. Sodium is found in many different minerals, of which the commonest is ordinary salt (sodium chloride), which occurs in vast quantities dissolved in seawater, as well as in solid deposits (halite). Others include amphibole, cryolite, soda niter and zeolite.
Sodium is relatively abundant in stars and the D spectral lines of this element are among the most prominent in star light. Though elemental sodium has a rather high vaporization temperature, its relatively high abundance and very intense spectral lines have allowed its presence to be detected by ground telescopes and confirmed by spacecraft (Mariner 10 and MESSENGER) in the thin atmosphere of the planet Mercury.
Compounds
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See also: Category:Sodium compounds
Sodium compounds are important to the chemical, glass, metal, paper, petroleum, soap, and textile industries. Hard soaps are generally sodium salt of certain fatty acids (potassium produces softer or liquid soaps).
The sodium compounds that are the most important to industries are common salt (NaCl), soda ash (Na2CO3), baking soda (NaHCO3), caustic soda (NaOH), sodium nitrate (NaNO3), di- and tri-sodium phosphates, sodium thiosulfate (hypo, Na2S2O3 · 5H2O), and borax (Na2B4O7 · 10H2O).
Biological role
Physiology and sodium ions
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Main article: Action potential
Sodium ions (often referred to as just “sodium”) are necessary for regulation of blood and body fluids, transmission of nerve impulses, heart activity, and certain metabolic functions. Interestingly, although sodium is needed by animals, which maintain high concentrations in their blood and extracellular fluids, the ion is not needed by plants, and is generally phytotoxic. A completely plant-based diet, therefore, will be very low in sodium. This requires some herbivores to obtain their sodium from salt licks and other mineral sources. The animal need for sodium is probably the reason for the highly-conserved ability to taste the sodium ion as “salty.” Receptors for the pure salty taste respond best to sodium, otherwise only to a few other small monovalent cations (Li+, NH4+, and somewhat to K+). Calcium ion (Ca2+) also tastes salty and sometimes bitter to some people but like potassium, can trigger other tastes.
Sodium ions play a diverse and important role in many physiological processes. Excitable animal cells, for example, rely on the entry of Na+ to cause a depolarization. An example of this is signal transduction in the human central nervous system, which depends on sodium ion motion across the nerve cell membrane, in all nerves.
Some potent neurotoxins, such as batrachotoxin, increase the sodium ion permeability of the cell membranes in nerves and muscles, causing a massive and irreversible depolarization of the membranes, with potentially fatal consequences. However, drugs with smaller effects on sodium ion motion in nerves may have diverse pharmacological effects which range from anti-depressant to anti-seizure actions.
Main articles: hyponatremia, hypernatremia, diuretic, and vasopressin
Sodium is the primary cation (positive ion) in extracellular fluids in animals and humans. These fluids, such as blood plasma and extracellular fluids in other tissues, bathe cells and carry out transport functions for nutrients and wastes. Sodium is also the principal cation in seawater, although the concentration there is about 3.8 times what it is normally in extracellular body fluids.
Although the system for maintaining optimal salt and water balance in the body is a complex one, one of the primary ways in which the human body keeps track of loss of body water is that osmoreceptors in the hypothalamus sense a balance of sodium and water concentration in extracellular fluids. Relative loss of body water will cause sodium concentration to rise higher than normal, a condition known as hypernatremia. This ordinarily results in thirst. Conversely, an excess of body water caused by drinking will result in too little sodium in the blood (hyponatremia), a condition which is again sensed by the hypothalamus, causing a decrease in vasopressin hormone secretion from the posterior pituitary, and a consequent loss of water in the urine, which acts to restore blood sodium concentrations to normal.
Severely dehydrated persons, such as people rescued from ocean or desert survival situations, usually have very high blood sodium concentrations. These must be very carefully and slowly returned to normal, since too-rapid correction of hypernatremia may result in brain damage from cellular swelling, as water moves suddenly into cells with high osmolar content.
Because the hypothalamus/osmoreceptor system ordinarily works well to cause drinking or urination to restore the body’s sodium concentrations to normal, this system can be used in medical treatment to regulate the body’s total fluid content, by first controlling the body’s sodium content. Thus, when a powerful diuretic drug is given which causes the kidneys to excrete sodium, the effect is accompanied by an excretion of body water (water loss accompanies sodium loss). This happens because the kidney is unable to efficiently retain water while excreting large amounts of sodium. In addition, after sodium excretion, the osmoreceptor system may sense lowered sodium concentration in the blood and then direct compensatory urinary water loss in order to correct the hyponatremic (low blood sodium) state.
In humans, a high-salt intake was demonstrated to attenuate nitric oxide production. Nitric oxide (NO) contributes to vessel homeostasis by inhibiting vascular smooth muscle contraction and growth, platelet aggregation, and leukocyte adhesion to the endothelium
Dietary uses
The most common sodium salt, sodium chloride (table salt), is used for seasoning (for example the English word “salad” refers to salt) and warm-climate food preservation, such as pickling and making jerky (the high osmotic content of salt inhibits bacterial and fungal growth). The human requirement for sodium in the diet is about 500 mg per day, which is typically less than a tenth as much as many diets “seasoned to taste.” Most people consume far more sodium than is physiologically needed. For certain people with salt-sensitive blood pressure, this extra intake may cause a negative effect on health.
Applications
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A low pressure sodium lamp, glowing with the light of sodium D spectral lines.
Sodium in its metallic form can be used to refine some reactive metals, such as zirconium and potassium, from their compounds. This alkali metal as the Na+ ion is vital to animal life. Other uses:
Commercial production
Sodium was first produced commercially in 1855 by thermal reduction of sodium carbonate with carbon at 1100 °C, in what is known as the Deville process.
Na2CO3 (liquid) + 2 C (solid) → 2 Na (vapor) + 3 CO (gas).
It is now produced commercially through the electrolysis of liquid sodium chloride, based on a process patented in 1924. This is done in a Downs Cell in which the NaCl is mixed with calcium chloride to lower the melting point below 700 °C. As calcium is less electropositive than sodium, no calcium will be formed at the anode. This method is less expensive than the previous Castner process of electrolyzing sodium hydroxide.
Very pure sodium can be isolated by the thermal decomposition of sodium azide.
Metallic sodium costs about 15 to 20 US cents per pound (US$0.30/kg to US$0.45/kg) in 1997 but reagent grade (ACS) sodium cost about US$35 per pound (US$75/kg) in 1990.
Precautions
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Extreme care is required in handling elemental/metallic sodium. Sodium is potentially explosive in water (depending on quantity) and is a caustic poison, since it is rapidly converted to sodium hydroxide on contact with moisture. The powdered form may combust spontaneously in air or oxygen. Sodium must be stored either in an inert (oxygen and moisture free) atmosphere (such as nitrogen or argon), or under a liquid hydrocarbon such as mineral oil or kerosene.
The reaction of sodium and water is a familiar one in chemistry labs, and is reasonably safe if amounts of sodium smaller than a pencil eraser are used and the reaction is done behind a plastic shield by people wearing eye protection. However, the sodium-water reaction does not scale up well, and is treacherous when larger amounts of sodium are used. Larger pieces of sodium melt under the heat of the reaction, and the molten ball of metal is buoyed up by hydrogen and may appear to be stably reacting with water, until splashing covers more of the reaction mass, causing thermal runaway and an explosion which scatters molten sodium, lye solution, and sometimes flame. (18.5 g explosion ) This behavior is unpredictable, and among the alkali metals it is usually sodium which invites this surprise phenomenon, because lithium is not reactive enough to do it, and potassium is so reactive that chemistry students are not tempted to try the reaction with larger potassium pieces.
Sodium is much more reactive than magnesium; a reactivity which can be further enhanced due to sodium’s much lower melting point. When sodium catches fire in air (as opposed to just the hydrogen gas generated from water by means of its reaction with sodium) it more easily produces temperatures high enough to melt the sodium, exposing more of its surface to the air and spreading the fire.
Few common fire extinguishers work on sodium fires. Water, of course, exacerbates sodium fires, as do water-based foams. CO2 and Halon are often ineffective on sodium fires, which reignite when the extinguisher dissipates. Among the very few materials effective on a sodium fire are Pyromet and Met-L-X. Pyromet is a NaCl/(NH4)2HPO4 mix, with flow/anti-clump agents. It smothers the fire, drains away heat, and melts to form an impermeable crust. This is the standard dry-powder canister fire extinguisher for all classes of fires. Met-L-X is mostly sodium chloride, NaCl, with approximately 5% Saran plastic as a crust-former, and flow/anti-clumping agents. It is most commonly hand-applied, with a scoop. Other extreme fire extinguishing materials include Lith+, a graphite based dry powder with an organophosphate flame retardant; and Na+, a Na2CO3-based material.
Because of the reaction scale problems discussed above, disposing of large quantities of sodium (more than 10 to 100 grams) must be done through a licensed hazardous materials disposer. Smaller quantities may be broken up and neutralized carefully with ethanol (which has a much slower reaction than water), or even methanol (where the reaction is more rapid than ethanol’s but still less than in water), but care should nevertheless be taken, as the caustic products from the ethanol or methanol reaction are just as hazardous to eyes and skin as those from water. After the alcohol reaction appears complete, and all pieces of reaction debris have been broken up or dissolved, a mixture of alcohol and water, then pure water, may then be carefully used for a final cleaning. This should be allowed to stand a few minutes until the reaction products are diluted more thoroughly and flushed down the drain. The purpose of the final water soak and wash of any reaction mass which may contain sodium is to ensure that alcohol does not carry unreacted sodium into the sink trap, where a water reaction may generate hydrogen in the trap space which can then be potentially ignited, causing a confined sink trap explosion.
See also
Alkali metals
Lithium
Li
Atomic Number: 3
Atomic Weight: 6.941
Melting Point: 453.69
Boiling Point: 1615
Electronegativity: 0.98
Sodium
Na
Atomic Number: 11
Atomic Weight: 22.990
Melting Point: 370.87
Boiling Point: 1156
Electronegativity: 0.96
Potassium
K
Atomic Number: 19
Atomic Weight: 39.098
Melting Point: 336.58
Boiling Point: 1032
Electronegativity: 0.82
Rubidium
Rb
Atomic Number: 37
Atomic Weight: 85.468
Melting Point: 312.46
Boiling Point: 961
Electronegativity: 0.82
Caesium
Cs
Atomic Number: 55
Atomic Weight: 132.905
Melting Point: 301.59
Boiling Point: 944
Electronegativity: 0.79
Francium
Fr
Atomic Number: 87
Atomic Weight: (223)
Melting Point: ?295
Boiling Point: ?950
Electronegativity: 0.7
References
External links
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Sodium
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Periodic table
H
He
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl
Ar
K
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
Rb
Sr
Y
Zr
Nb
Mo
Tc
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
Cs
Ba
La
Ce
Pr
Nd
Pm
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
Hf
Ta
W
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
Fr
Ra
Ac
Th
Pa
U
Np
Pu
Am
Cm
Bk
Cf
Es
Fm
Md
No
Lr
Rf
Db
Sg
Bh
Hs
Mt
Ds
Rg
Uub
Uut
Uuq
Uup
Uuh
Uus
Uuo
Alkali metals
Alkaline earth metals
Lanthanides
Actinides
Transition elements
Other metals
Metalloids
Other nonmetals
Halogens
Noble gases
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Categories: Desiccants | Dietary minerals | Sodium | Reducing agentsHidden category: Articles needing additional references from February 2008
Cytochalasin B
Other names
Phomin
Molecular formula
C29H37NO5
Identifiers
CAS number
Properties
Molar mass
479.6
Solubility in water
1.280 mg/L
Hazards
MSDS
Cytochalasin B MSDS from Fermentek
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references
Cytochalasin B is a cell-permeable mycotoxin. It inhibits cytoplasmic division by blocking the formation of contractile microfilaments. It inhibits cell movement and induces nuclear extrusion. Cytochalasin B shortens actin filaments by blocking monomer addition at the fast-growing end of polymers. Cytochalasin B inhibits glucose transport and platelet aggregation. It blocks adenosine-induced apoptotic body formation without affecting activation of endogenous ADP-ribosylation in leukemia HL-60 cells. It is also used in cloning through nuclear transfer. Here enucleated recipient cells are treated with Hoechst stain containing cytochalsin B. Cytochalasin B makes the walls of the oocytes smoother and makes it easy for micro-manipulation so that the zona pellucida is not so rigid and can be easily pierced by the micro-needles.
This alkaloid is isolated from a fungus, Helminthosporium dermatioideum.
References
External links
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