Vanadium(V) oxide
Encyclopedia
Vanadium oxide (vanadia) is the chemical compound
with the formula
V2O5. Commonly known as vanadium pentoxide, this brown/yellow solid is the most stable and common compound
of vanadium
. Upon heating it reversibly loses oxygen. Related to this ability, V2O5 catalyses several useful aerobic oxidation reactions, the largest scale of which underpins the production of sulfuric acid
from sulfur dioxide
. It is a poison
ous brown/yellow solid which, because of its high oxidation state
, is both an amphoteric oxide and an oxidising agent
. Unlike most metal oxides, it dissolves
slightly in water to give a pale yellow, acidic solution. When this compound is formed by precipitation from aqueous solution, then its color is deep orange instead of brown/yellow.
The mineral form of this compound, shcherbinaite, is extremely rare, almost always found among fumaroles. A mineral trihydrate
, V2O5·3H2O, is also known under the name of navajoite.
It also reacts with strong alkali
to form polyoxovanadates, which have a complex structure that depends on pH
. If excess aqueous sodium hydroxide is used, the product is a colourless salt
, sodium orthovanadate
, Na3VO4. If acid is slowly added to a solution of Na3VO4, the colour gradually deepens through orange to red before brown hydrated V2O5 precipitates around pH 2. These solutions contain mainly the ions HVO42− and V2O74− between pH 9 and pH 13, but below pH 9 more exotic species such as V4O124− and HV10O285− predominate.
Thionyl chloride
converts it to VOCl3
:
(VO(H2O)52+). This conversion illustrates the redox
properties of V2O5. For example, hydrochloric acid
and hydrobromic acid
are oxidised to the corresponding halogen
, e.g.,
Solid V2O5 is reduced by oxalic acid
, carbon monoxide
, and sulfur dioxide
to give vanadium(IV) oxide
, VO2 as a deep-blue solid. Further reduction using hydrogen
or excess CO can lead to complex mixtures of oxides such as V4O7 and V5O9 before black V2O3 is reached. Vanadates or vanadyl(V) compounds in acid solution are reduced by zinc amalgam through the interestingly colorful pathway:
The ions are, of course, all hydrated to varying degrees.
metal and ferrovanadium. A vanadium ore or vanadium-rich residue is treated with sodium carbonate
to produce sodium metavanadate
, NaVO3. This material is then acidified to pH 2–3 using H2SO4
to yield a precipitate of "red cake" (see above). The red cake is then melted at 690 °C to produce the crude V2O5.
Vanadium(V) oxide is produced when vanadium
metal is heated with excess oxygen
, but this product is contaminated with other, lower oxides. A more satisfactory laboratory preparation involves the decomposition of ammonium metavanadate
at around 200 °C:
and ferrosilicon
, with lime added to form a calcium silicate
slag
. Aluminium
may also be used, producing the iron-vanadium alloy along with alumina as a by-product. In 2005 a shortage of V2O5 caused its price to rise to $40/kg, which in turn caused a rise in the price of ferrovanadium.
, an important industrial chemical with an annual worldwide production of 165 million metric tons in 2001, with an approximate value of US$8 billion. Vanadium(V) serves the crucial purpose of catalysing the mildly exothermic
oxidation
of sulfur dioxide to sulfur trioxide
by air in the contact process
:
The discovery of this simple reaction, for which V2O5 is the most effective catalyst, allowed sulfuric acid to become the cheap commodity chemical it is today. The reaction is performed between 400 and 620 °C; below 400 °C the V2O5 is inactive as a catalyst, and above 620 °C it begins to break down. Since it is known that V2O5 can be reduced to VO2 by SO2, one likely catalytic cycle is as follows:
followed by
Paradoxically, it is also used as catalyst in the selective catalytic reduction
(SCR) of NOx emissions in some power plants. Due to its effectiveness in converting sulfur dioxide into sulfur trioxide, and thereby sulfuric acid, special care must be taken with the operating temperatures and placement of a power plant's SCR unit when firing sulfur-containing fuels.
is another important industrial material, used for the manufacture of polyester
resins and alkyd resins. Vanadium(V) oxide can catalyse its production from a variety of organic starting materials such as n-butane
, furfural
and benzene
, the last of which is the usual commercial method. In a related process, phthalic anhydride
, used for making plasticisers for PVC
manufacture, may be produced by V2O5 catalysed oxidation of ortho-xylene
or naphthalene
at 350–400 °C.
s and microbolometer
arrays for thermal imaging. It also finds application as an ethanol sensor in ppm levels (up to 0.1 ppm).
Possible new uses include the preparation of bismuth vanadate ceramics for use in solid oxide fuel cell
s. Another new application is in vanadium redox batteries
, a type of flow battery
used for energy storage, including large power facilities such as wind farm
s.
of about 470 mg/kg. The greater problem is with inhalation of the dust, where the LD50
ranges from 4-11mg/kg for a 14 day exposure. Vanadate (VO43−), formed by hydrolysis of V2O5 at high pH, appears to inhibit enzymes that process phosphate (PO43−). However the exact mode of action remains elusive.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
V2O5. Commonly known as vanadium pentoxide, this brown/yellow solid is the most stable and common compound
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
of vanadium
Vanadium
Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature...
. Upon heating it reversibly loses oxygen. Related to this ability, V2O5 catalyses several useful aerobic oxidation reactions, the largest scale of which underpins the production of sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
from sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
. It is a poison
Poison
In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....
ous brown/yellow solid which, because of its high oxidation state
Oxidation state
In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...
, is both an amphoteric oxide and an oxidising agent
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....
. Unlike most metal oxides, it dissolves
Solubility
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
slightly in water to give a pale yellow, acidic solution. When this compound is formed by precipitation from aqueous solution, then its color is deep orange instead of brown/yellow.
The mineral form of this compound, shcherbinaite, is extremely rare, almost always found among fumaroles. A mineral trihydrate
Hydrate
Hydrate is a term used in inorganic chemistry and organic chemistry to indicate that a substance contains water. The chemical state of the water varies widely between hydrates, some of which were so labeled before their chemical structure was understood....
, V2O5·3H2O, is also known under the name of navajoite.
Acid-base reactions
V2O5 is an amphoteric oxide. Thus it reacts with strong non-reducing acids to form solutions containing the pale yellow salts containing dioxovanadium(V) centers:- V2O5 + 2 HNO3 → 2 VO2(NO3) + H2O
It also reacts with strong alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...
to form polyoxovanadates, which have a complex structure that depends on pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
. If excess aqueous sodium hydroxide is used, the product is a colourless salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
, sodium orthovanadate
Sodium orthovanadate
Sodium orthovanadate is the chemical compound Na3VO4 and contains the tetrahedral VO43−. It is an inhibitor of protein tyrosine phosphatases, alkaline phosphatases and a number of ATPases, most likely acting as a phosphate analogue...
, Na3VO4. If acid is slowly added to a solution of Na3VO4, the colour gradually deepens through orange to red before brown hydrated V2O5 precipitates around pH 2. These solutions contain mainly the ions HVO42− and V2O74− between pH 9 and pH 13, but below pH 9 more exotic species such as V4O124− and HV10O285− predominate.
Thionyl chloride
Thionyl chloride
Thionyl chloride is an inorganic compound with the formula SOCl2. It is a reactive chemical reagent used in chlorination reactions. It is a colorless, distillable liquid at room temperature and pressure that decomposes above 140 °C. Thionyl chloride is sometimes confused with sulfuryl...
converts it to VOCl3
Vanadium oxytrichloride
Vanadium oxytrichloride is the inorganic compound with the formula VOCl3. This distillable liquid hydrolyzes readily in air and is a strong oxidant. It is used as a reagent in organic synthesis.-Properties:...
:
- V2O5 + 3 SOCl2 → 2 VOCl3 + 3 SO2
Redox reactions
V2O5 is easily reduced in acidic media to the stable vanadium(IV) species, the blue vanadyl ionVanadyl ion
The vanadyl or oxovanadium cation, [VO]2+, is a blue-coloured vanadium oxocation. It is one of the most stable diatomic ions known and forms a wide range of complexes.-Compounds containing the vanadyl ion:* vanadyl, VO2...
(VO(H2O)52+). This conversion illustrates the redox
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....
properties of V2O5. For example, hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
and hydrobromic acid
Hydrobromic acid
Hydrobromic acid is a strong acid formed by dissolving the diatomic molecule hydrogen bromide in water. "Constant boiling" hydrobromic acid is an aqueous solution that distills at 124.3 °C and contains 47.6% HBr by weight, which is 8.89 mol/L. Hydrobromic acid has a pKa of −9, making it a...
are oxidised to the corresponding halogen
Halogen
The halogens or halogen elements are a series of nonmetal elements from Group 17 IUPAC Style of the periodic table, comprising fluorine , chlorine , bromine , iodine , and astatine...
, e.g.,
- V2O5 + 6HCl + 7H2O → 2[VO(H2O)5]2+ + 4Cl− + Cl2
Solid V2O5 is reduced by oxalic acid
Oxalic acid
Oxalic acid is an organic compound with the formula H2C2O4. This colourless solid is a dicarboxylic acid. In terms of acid strength, it is about 3,000 times stronger than acetic acid. Oxalic acid is a reducing agent and its conjugate base, known as oxalate , is a chelating agent for metal cations...
, carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
, and sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
to give vanadium(IV) oxide
Vanadium(IV) oxide
Vanadium oxide is the chemical compound VO2. It is formed in the contact process from V2O5, which acts as a catalyst.Vanadium oxide is amphoteric, dissolving in non-oxidising acids to give the vanadyl ion, [VO]2+ and in alkali to give the [V4O9]2− ion, or at high pH [VO4]4−...
, VO2 as a deep-blue solid. Further reduction using hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
or excess CO can lead to complex mixtures of oxides such as V4O7 and V5O9 before black V2O3 is reached. Vanadates or vanadyl(V) compounds in acid solution are reduced by zinc amalgam through the interestingly colorful pathway:
| VO2+ | → | VO2+ | → | V3+ | → | V2+ |
| yellow | blue | green | purple | |||
The ions are, of course, all hydrated to varying degrees.
Preparation
Technical grade V2O5 is produced as a black powder used for the production of vanadiumVanadium
Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature...
metal and ferrovanadium. A vanadium ore or vanadium-rich residue is treated with sodium carbonate
Sodium carbonate
Sodium carbonate , Na2CO3 is a sodium salt of carbonic acid. It most commonly occurs as a crystalline heptahydrate, which readily effloresces to form a white powder, the monohydrate. Sodium carbonate is domestically well-known for its everyday use as a water softener. It can be extracted from the...
to produce sodium metavanadate
Sodium metavanadate
Sodium metavanadate is a yellow solid which is soluble in water. Its use is limited to its hygroscopic property. Its natural forms include mineral metamunirite and a dihydrate, munirite. Both are very rare, metamunirite is now known only from V- and U-bearing sandstone formations of...
, NaVO3. This material is then acidified to pH 2–3 using H2SO4
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
to yield a precipitate of "red cake" (see above). The red cake is then melted at 690 °C to produce the crude V2O5.
Vanadium(V) oxide is produced when vanadium
Vanadium
Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature...
metal is heated with excess oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, but this product is contaminated with other, lower oxides. A more satisfactory laboratory preparation involves the decomposition of ammonium metavanadate
Ammonium metavanadate
Ammonium metavanadate, NH4VO3, is a yellow crystalline solid which is water soluble inorganic acid that acts as insulin mimic. It functions as a catalyst to certain reactions and is known to have toxic effects in certain species. It has been found in slags and fly ash from coal burning which has...
at around 200 °C:
- 2 NH4VO3 → V2O5 + 2 NH3 + H2O
Ferrovanadium production
In terms of quantity, the dominant use for vanadium(V) oxide is in the production of ferrovanadium (see above). The oxide is heated with scrap ironIron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
and ferrosilicon
Ferrosilicon
Ferrosilicon, or ferrosilicium, is a ferroalloy, an alloy of iron and silicon with between 15% and 90% silicon. It contains a high proportion of iron silicides. Its melting point is about 1200 °C to 1250 °C with a boiling point of 2355 °C...
, with lime added to form a calcium silicate
Calcium silicate
Calcium silicate is the chemical compound Ca2SiO4, also known as calcium orthosilicate and sometimes formulated 2CaO.SiO2. It is one of group of compounds obtained by reacting calcium oxide and silica in various ratios e.g. 3CaO.SiO2, Ca3SiO5; 2CaO.SiO2, Ca2SiO4; 3CaO.2SiO2, Ca3Si2O7 and...
slag
Slag
Slag is a partially vitreous by-product of smelting ore to separate the metal fraction from the unwanted fraction. It can usually be considered to be a mixture of metal oxides and silicon dioxide. However, slags can contain metal sulfides and metal atoms in the elemental form...
. Aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
may also be used, producing the iron-vanadium alloy along with alumina as a by-product. In 2005 a shortage of V2O5 caused its price to rise to $40/kg, which in turn caused a rise in the price of ferrovanadium.
Sulfuric acid production
Another important use of vanadium(V) oxide is in the manufacture of sulfuric acidSulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
, an important industrial chemical with an annual worldwide production of 165 million metric tons in 2001, with an approximate value of US$8 billion. Vanadium(V) serves the crucial purpose of catalysing the mildly exothermic
Exothermic reaction
An exothermic reaction is a chemical reaction that releases energy in the form of light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation:-Overview:...
oxidation
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....
of sulfur dioxide to sulfur trioxide
Sulfur trioxide
Sulfur trioxide is the chemical compound with the formula SO3. In the gaseous form, this species is a significant pollutant, being the primary agent in acid rain. It is prepared on massive scales as a precursor to sulfuric acid.-Structure and bonding:Gaseous SO3 is a trigonal planar molecule of...
by air in the contact process
Contact process
The contact process is the current method of producing sulphuric acid in the high concentrations needed for industrial processes. Platinum was formerly employed as a catalyst for the reaction, but as it is susceptible to poisoning by arsenic impurities in the sulfur feedstock, vanadium oxide is...
:
- 2 SO2 + O2 2 SO3
The discovery of this simple reaction, for which V2O5 is the most effective catalyst, allowed sulfuric acid to become the cheap commodity chemical it is today. The reaction is performed between 400 and 620 °C; below 400 °C the V2O5 is inactive as a catalyst, and above 620 °C it begins to break down. Since it is known that V2O5 can be reduced to VO2 by SO2, one likely catalytic cycle is as follows:
- SO2 + V2O5 → SO3 + 2VO2
followed by
- 2VO2 +½O2 → V2O5
Paradoxically, it is also used as catalyst in the selective catalytic reduction
Selective catalytic reduction
Selective catalytic reduction is a means of converting nitrogen oxides, also referred to as with the aid of a catalyst into diatomic nitrogen , , and water, . A gaseous reductant, typically anhydrous ammonia, aqueous ammonia or urea, is added to a stream of flue or exhaust gas and is absorbed...
(SCR) of NOx emissions in some power plants. Due to its effectiveness in converting sulfur dioxide into sulfur trioxide, and thereby sulfuric acid, special care must be taken with the operating temperatures and placement of a power plant's SCR unit when firing sulfur-containing fuels.
Other oxidations
Maleic anhydrideMaleic anhydride
Maleic anhydride is an organic compound with the formula C2H22O. It is the acid anhydride of maleic acid and in its pure state it is a colourless or white solid with an acrid odour....
is another important industrial material, used for the manufacture of polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
resins and alkyd resins. Vanadium(V) oxide can catalyse its production from a variety of organic starting materials such as n-butane
Butane
Butane is a gas with the formula C4H10 that is an alkane with four carbon atoms. The term may refer to any of two structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, butane refers only to the unbranched n-butane isomer; the other one being called "methylpropane" or...
, furfural
Furfural
Furfural is an organic compound derived from a variety of agricultural byproducts, including corncobs, oat, wheat bran, and sawdust. The name furfural comes from the Latin word , meaning bran, referring to its usual source....
and benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
, the last of which is the usual commercial method. In a related process, phthalic anhydride
Phthalic anhydride
Phthalic anhydride is the organic compound with the formula C6H42O. It is the anhydride of phthalic acid. This colourless solid is an important industrial chemical, especially for the large-scale production of plasticizers for plastics. In 2002, approximately 4.6 billion kilograms were...
, used for making plasticisers for PVC
Polyvinyl chloride
Polyvinyl chloride, commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups having one hydrogen replaced by chloride. Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene. PVC is widely used in...
manufacture, may be produced by V2O5 catalysed oxidation of ortho-xylene
Xylene
Xylene encompasses three isomers of dimethylbenzene. The isomers are distinguished by the designations ortho- , meta- , and para- , which specify to which carbon atoms the two methyl groups are attached...
or naphthalene
Naphthalene
Naphthalene is an organic compound with formula . It is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings...
at 350–400 °C.
Other applications
Due to its high thermal coefficient of resistance, vanadium(V) oxide finds use as a detector material in bolometerBolometer
A bolometer is a device for measuring the power of incident electromagnetic radiation via the heating of a material with a temperature-dependent electrical resistance. It was invented in 1878 by the American astronomer Samuel Pierpont Langley...
s and microbolometer
Microbolometer
A microbolometer is a specific type of bolometer used as a detector in a thermal camera. Infrared radiation with wavelengths between 7.5-14 μm strikes the detector material, heating it, and thus changing its electrical resistance. This resistance change is measured and processed into temperatures...
arrays for thermal imaging. It also finds application as an ethanol sensor in ppm levels (up to 0.1 ppm).
Possible new uses include the preparation of bismuth vanadate ceramics for use in solid oxide fuel cell
Fuel cell
A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
s. Another new application is in vanadium redox batteries
Vanadium redox battery
The vanadium redox battery is a type of rechargeable flow battery that employs vanadium ions in different oxidation states to store chemical potential energy...
, a type of flow battery
Flow battery
A flow battery is a form of rechargeable battery in which electrolyte containing one or more dissolved electroactive species flows through an electrochemical cell that converts chemical energy directly to electricity...
used for energy storage, including large power facilities such as wind farm
Wind farm
A wind farm is a group of wind turbines in the same location used to produce electric power. A large wind farm may consist of several hundred individual wind turbines, and cover an extended area of hundreds of square miles, but the land between the turbines may be used for agricultural or other...
s.
Biological activity
Vanadium(V) oxide exhibits modest toxicity to humans, with an LD50LD50
In toxicology, the median lethal dose, LD50 , LC50 or LCt50 of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after a specified test duration...
of about 470 mg/kg. The greater problem is with inhalation of the dust, where the LD50
LD50
In toxicology, the median lethal dose, LD50 , LC50 or LCt50 of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after a specified test duration...
ranges from 4-11mg/kg for a 14 day exposure. Vanadate (VO43−), formed by hydrolysis of V2O5 at high pH, appears to inhibit enzymes that process phosphate (PO43−). However the exact mode of action remains elusive.
External links
- How Vanadium Oxide Is Used In Energy Storage
- Vanadium Pentoxide and other Inorganic Vanadium Compounds (Concise International Chemical Assessment DocumentConcise International Chemical Assessment DocumentConcise International Chemical Assessment Documents are published by the World Health Organization within the framework of the International Programme on Chemical Safety...
29)