Vanadium

group 5 · period 4 · d-block · transition metal

fullVanadium has no WHO, EU or federal US drinking water limit, but the US monitored it nationally under UCMR 3, California has carried a 50 µg/L notification level since 2000 because natural groundwater so often contains it, Abu Dhabi limits it to sewer, and oil, steel and vanadium processing effluents carry it as the soluble vanadate anion.

Typical wastewaters

vanadium ore mining, smelting and processing vanadium(V) as the vanadate anions H₂VO₄⁻ and HVO₄²⁻ in oxic effluent; real wastewaters were tested on anion exchangers
petroleum refining and heavy oil combustion (spent catalyst, boiler ash and residue leachate) vanadate leached from boiler ash, spent catalysts and petroleum residues no effluent concentrations were read
alumina refining bauxite residue (red mud) leachate vanadate in pH 13 leachate; only 5 to 16 percent removed on neutralisation with HCl, gypsum or seawater, so vanadium persists in treated red mud leachate Ajka, Hungary
basic oxygen furnace steel slag leachate V(IV) in the slag oxidising to vanadate V(V) during leaching; vanadium release significantly high while chromium stays as Cr(III)
centralised waste treatment (metals treatment and recovery) dissolved vanadium in treated metal-bearing waste effluent BPT 0.218 mg/L daily maximum, 0.0662 mg/L monthly average
coal combustion residual leachate vanadium among the BAT treated pollutants in combustion residual leachate
coal mine acid drainage dissolved vanadium 0.17 to 0.66 mg/L in acid mine drainage affected surface water, west-central Indiana (Allen and others 1996)
uranium ore processing effluent vanadium with titanium and uranium in contaminated effluent from uranium ore mine processing

1 · Identity

Symbol, number: V, 23
Oxidation states in water: +5 as vanadate in oxic water (the cation VO₂⁺ below about pH 3, the anions H₂VO₄⁻, HVO₄²⁻ and VO₄³⁻ and polyvanadates above it); +4 as the vanadyl ion VO²⁺ under mildly reducing conditions; +3 in strongly reducing water, hydrolysed and adsorbed on iron oxides.
Note: The element entry gives the ores, the sulfuric acid catalyst and the batteries, and already states that vanadium in oxidising neutral to alkaline water is soluble vanadate while reduced forms adsorb onto iron oxides. This chapter adds the analytical and regulatory picture and the anion chemistry that decides removal.

2 · Occurrence in water

Natural sources: Weathering of vanadium bearing magnetite, phosphate rock and volcanic rock; natural groundwater in volcanic terrain carries vanadate, which is why California found a high number of detections reflecting natural occurrence when it set its notification level.
Anthropogenic sources: Mining, smelting and processing of vanadium ores (Wolowicz and Hubicki); petroleum refining and heavy oil combustion (crude oil, oil shale and tar sands carry organic vanadium complexes, and petroleum residues, spent catalysts and boiler ash are the secondary feed of producers, the element entry); vanadium slag from steelmaking; sulfuric acid plant catalyst waste; redox flow battery electrolyte.

matrix	typical range	note
seawater	2.5 µg/Lsingle figure	estimated oceanic abundance, Jefferson Lab figure via PubChem (2.5 x 10⁻3 mg/L)
drinking water, USA	monitored at a minimum reporting level of 0.2 µg/Lno range read	UCMR 3 monitoring 2013 to 2015 by EPA 200.8; the occurrence results were not read this session

3 · Speciation

In oxic water vanadium is vanadium(V), and above about pH 3 vanadium(V) is an anion: H₂VO₄⁻ around neutral pH, HVO₄²⁻ in alkaline water, with polyvanadates at high concentration and the VO₂⁺ cation only in acid. That anionic form is why vanadium behaves like arsenate and phosphate in treatment: it adsorbs on iron and aluminium hydroxides and exchanges on anion resins but is not precipitated as a hydroxide. Under reducing conditions vanadium(IV), the vanadyl ion VO²⁺, and vanadium(III) hydrolyse, adsorb and precipitate with iron oxides, which is the geochemical trap and the basis of reductive removal.

condition	dominant species	note
oxic water, pH above 3	H₂VO₄⁻, HVO₄²⁻, VO₄³⁻ (monovanadates) and polyvanadates	the mobile form in groundwater and effluent
acid water, pH below 3	VO₂⁺ (dioxovanadium(V) cation)	acid leach liquors and pickle
reducing water	VO²⁺ (vanadyl, +4) and vanadium(III) hydroxy species, adsorbed on and coprecipitated with iron oxides	the element entry: reduced forms hydrolyse and adsorb onto iron oxides

Solubility: Vanadium(V) salts of sodium and potassium are soluble; vanadate is removed by adsorption and coprecipitation, not by a simple solubility limit at neutral pH. Constants are not quoted because the sources read print none.
Hydrolysis: Vanadate is a weak polyprotic acid whose speciation shifts from cation to anion near pH 3 and to the divalent anion in alkaline water (Wolowicz and Hubicki); vanadyl hydrolyses and precipitates under reducing conditions.
Complexation: Vanadium forms organic complexes in crude oil (porphyrins) and adsorbs on iron oxides; ligand constants were not read.
Precipitates: Vanadyl and vanadium(III) hydroxides and oxides with iron oxides; calcium and iron vanadates in high concentration treatment; ammonium metavanadate in hydrometallurgy (the element entry).

\ce{VO2^+ + 2 H2O <=> H2VO4^- + 2 H+}

cation to anion transition of vanadium(V) near pH 3 (Wolowicz and Hubicki)

\ce{H2VO4^- <=> HVO4^2- + H+}

neutral to alkaline water; the divalent anion dominates in alkaline water; constant not read

\ce{10 H2VO4^- + 4 H+ -> V10O28^6- + 12 H2O}

polymerisation to decavanadate, the orange species of concentrated acid vanadate liquors; it needs roughly millimolar total vanadium and pH below about 6, so it belongs to leach liquors, spent catalyst washings and flow battery electrolyte, not to the microgram per litre vanadium of a groundwater supply (Baes and Mesmer, the vanadium section, from the chapter, not re-read)

\ce{H2VO4^- + 4 H+ + e- -> VO^2+ + 3 H2O}

the vanadium(V) to vanadium(IV) couple, the line between the mobile anion and the vanadyl cation and the step every reductive removal uses; written here as the electron balance of the reduction the review and the element entry describe in words, no standard potential was read

\ce{VO^2+ + 2 H2O -> VO(OH)2 (s) + 2 H+}

hydrolysis and precipitation of the vanadyl ion in reducing, near neutral water; this is the geochemical trap the element entry describes when it says reduced vanadium hydrolyses and adsorbs onto iron oxides; no hydrolysis constant or solubility product was read

4 · Role in treatment

as a problem

natural vanadate in groundwater supplies

soluble anion not removed by conventional treatment

California revised its notification level from 15 to 50 µg/L partly because of the high number of detections reflecting natural occurrence

vanadium in oil and steel effluents

vanadate leaches from boiler ash, spent catalyst and slag

the element entry lists petroleum residues, spent catalysts and utility ash as vanadium feeds; no effluent concentrations were read

ICP-MS interference

chloride oxide ion overlaps mass 51 in chloride rich samples

EPA 200.8 Table 2 lists ClO⁺ among chloride matrix molecular ions; brines and seawater need correction or a collision cell

5 · Removal and control

adsorption on iron oxides and ferric coagulation

vanadate adsorbs on freshly precipitated ferric hydroxide and iron oxide media as arsenate does

\ce{Fe(OH)3 (s) + H2VO4^- -> Fe(OH)2H2VO4 (s) + OH-}

Wolowicz and Hubicki list adsorption and coagulation among the methods developed; the element entry gives iron oxide adsorption as the natural trap; pH and capacity figures not read; the adsorption is written as the ligand exchange this book uses for arsenate on ferric hydroxide, since vanadate is the same kind of tetrahedral oxo-anion, the review names the process without a surface species

Efficiency: not quoted
Interferences: phosphate, silicate and arsenate compete for the same sites

anion exchange

vanadate anions exchange on strong and weak base resins

\ce{RCl + H2VO4^- -> RH2VO4 + Cl^-}

the study read tested vanadium(V) on anion exchangers and real wastewaters; written in the usual resin notation for a chloride form strong base bed (R one exchange site)

Efficiency: not quoted here
Interferences: sulfate and chloride compete

chemical reduction and precipitation

vanadium(V) reduced to vanadium(IV) or (III) and precipitated with iron or as hydroxide

\ce{H2VO4^- + Fe^2+ + 2 H2O -> VO(OH)2 (s) + Fe(OH)3 (s) + H+}

listed among the methods (chemical precipitation, photocatalytic reduction, microbiological treatment); the iron(II) route written as the one electron balance, vanadium(V) to vanadyl against iron(II) to ferric hydroxide, so the two solids come down together; the review names chemical reduction and precipitation without a stoichiometry

Efficiency: not quoted

membrane filtration

reverse osmosis and nanofiltration reject the vanadate anion

listed among the methods; no figures read

Efficiency: not quoted

6 · Analytics

method	standard	detection limit	note
ICP-MS	EPA 200.8 (mass 51); ISO 17294-2	EPA 200.8 instrument detection limit 0.02 µg/L scanning, 0.006 µg/L selected ion monitoring; UCMR 3 minimum reporting level 0.2 µg/L	ClO⁺ from chloride interferes at mass 51
ICP-OES	EPA 200.7 (292.402 nm); ISO 11885	EPA 200.7 instrument detection limit 7.5 µg/L, total recoverable method detection limit 0.003 mg/L
graphite furnace AAS	ISO 15586 (vanadium among its elements)	not read
colorimetry	Standard Methods 3500-V	not read	cited from the Standard Methods table of contents

Sampling pitfalls: Acidify for total vanadium; filter first for dissolved. Speciation between vanadium(IV) and (V) changes on aeration and is not preserved by acidification; no speciation protocol was read.

7 · Regulatory limits

Limits change, and many are set locally. Treat these as the published values to start from, not as your compliance target: check the standard in force at your site and the numbers written into your own permit.

drinking water

body	limit	note
WHO GDWQ 4th ed. with addenda (2022)	no guideline	no chemical fact sheet for vanadium exists on the WHO fact sheet path
EU DWD 2020/2184	not set	vanadium is not in Annex I
US EPA	not regulated	absent from the primary and secondary standards; monitored under UCMR 3 (2013 to 2015) by EPA 200.8 at a 0.2 µg/L minimum reporting level
California SWRCB Division of Drinking Water, notification level	0.05 mg/L	established in 2000 at 0.015 mg/L and revised in late 2000 or early 2001 to 0.05 mg/L by changing the relative source contribution from 0.2 to 0.6 in view of the many natural detections; endpoint developmental and reproductive effects in rats (OEHHA 2000)

discharge

body	limit	note
EU CWW BREF BAT-AEL (Decision 2016/902)	not set	not a BAT 12 parameter
US EPA 40 CFR 423.13, steam electric FGD wastewater	not set other categories not read	no vanadium limit; FGD limits cover arsenic, mercury, selenium and nitrate plus nitrite
Abu Dhabi ADS 23/2017, discharge to the marine environment (EAD)	not set region-dependent	vanadium is not in Table 1
Abu Dhabi DoE Trade Effluent Control Regulations 2022, discharge to sewer	1 mg/L region-dependent; sewer discharge	Table A₄ maximum allowable concentration

industry thresholds

sector	body	limit	note
textile	ZDHC Wastewater Guidelines v₂.1 (2022)	not set	vanadium is not a ZDHC parameter

8 · Health and environmental effects

Toxicity: California's notification level rests on developmental and reproductive effects in rats (OEHHA 2000). The element entry: an essential trace element for some species including humans at about 0.01 mg a day, but several compounds are toxic.
Bioaccumulation: Not addressed in the sources read.
Ecotoxicity: No US EPA aquatic life criterion; vanadium is listed among substances discharged from ore processing in the ledger's mining chapter (the element entry).

Flags

No occurrence range for groundwater, surface water or drinking water was read; the UCMR 3 data files and the California detection statistics were not opened.
No effluent concentration for refineries, steelworks or vanadium plants was read; figures seen only in search summaries are not quoted.
The seawater figure is a single PubChem abundance figure.
The California notification level history is quoted from the state overview document; the current notification level page was not reachable.
The mass 51 interference is from the EPA 200.8 chloride matrix list; the mass assignment is arithmetic on 35Cl plus 16O.
Removal efficiencies are not quoted because the review read gives the methods without figures in the sections read.

Gaps

Vanadium occurrence data (UCMR 3 results, California groundwater) were not read.
No vanadate acid dissociation constants or adsorption constants were read.
No removal efficiencies for iron adsorption, ion exchange or membranes were read.
No WHO evaluation of vanadium exists in the fact sheets; the EPA contaminant candidate list status was not read.
Refinery and steel effluent vanadium concentrations belong to the ledger's chapters and were not sourced here.
No surface complexation or ion exchange constants for vanadate were read; the adsorption, exchange and iron(II) reduction equations are written as ligand exchange and electron balances by analogy with arsenate and iron.

Sources

Wolowicz A., Hubicki Z., Vanadium(V) removal from aqueous solutions and real wastewaters onto anion exchangers, Molecules 27(17), 5432 (2022), doi 10.3390/molecules27175432, introduction
California State Water Resources Control Board, Division of Drinking Water, Drinking Water Notification Levels and Response Levels: An Overview (copy held by US EPA Region 9), table and notes 16 and 30
US EPA, Third Unregulated Contaminant Monitoring Rule (UCMR 3), Table 1 of contaminants, methods and minimum reporting levels
Directive (EU) 2020/2184 on the quality of water intended for human consumption (recast), Annex I Parts B and C and Annex III
US EPA, National Primary Drinking Water Regulations (table of MCLs and treatment techniques)
WHO GDWQ 4th ed. with addenda (2022), chapter 12 chemical fact sheets on the WHO fact sheet path (no vanadium sheet exists at that path)
Commission Implementing Decision (EU) 2016/902 establishing BAT conclusions for common waste water and waste gas treatment/management systems in the chemical sector (CWW), BAT 12 Tables 1 and 2
40 CFR 423.13, Effluent limitations guidelines representing BAT, steam electric power generating point source category
Abu Dhabi Specification ADS 23/2017, Environmental Specifications for Land-Based Liquid Discharges to the Marine Environment (Environment Agency Abu Dhabi), Table 1
Abu Dhabi Department of Energy, Trade Effluent Control Regulations 2022 (DoE/PD/R01/005, effective 1 January 2022), Appendix Tables A2 and A4
ZDHC Wastewater Guidelines Version 2.1 (November 2022), conventional parameters, anions and metals tables and sludge Table 4A
US EPA Method 200.8, Revision 5.4 (1994), Determination of trace elements in waters and wastes by ICP-MS, Table 1 (instrument detection limits) and Table 2 (molecular ion interferences)
US EPA Method 200.7, Revision 4.4 (1994), Determination of metals and trace elements in water and wastes by ICP-AES, Table 1 (wavelengths and instrument detection limits), Table 4 (method detection limits) and Table 5 (argon plasma conditions)
ISO 17294-2:2023, Water quality. Application of ICP-MS. Part 2: Determination of selected elements including uranium isotopes
ISO 11885:2007, Water quality. Determination of selected elements by inductively coupled plasma optical emission spectrometry (ICP-OES)
ISO 15586:2003, Water quality. Determination of trace elements using atomic absorption spectrometry with graphite furnace (Ag, Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, Zn)
Standard Methods for the Examination of Water and Wastewater (online edition), table of contents (Part 3000 metals, including 3500-K Potassium and 3500-V Vanadium)
PubChem element summary for vanadium; estimated oceanic abundance 2.5 x 10^-3 mg/L (PUG View, reference 5, Jefferson Lab)
The Element Book, layer 1 entry for vanadium (data/elements/V.json and data/reference/text/V.json)
Burke I. T., Peacock C. L., Lockwood C. L., Stewart D. I., Mortimer R. J., Ward M. B., Renforth P. and others, Behavior of aluminum, arsenic, and vanadium during the neutralization of red mud leachate by HCl, gypsum, or seawater, Environmental Science and Technology 47(12), 6527 to 6535 (2013), doi 10.1021/es4010834 (abstract)
Chaurand P., Rose J., Briois V., Olivi L., Hazemann J. L., Proux O., Domas J., Bottero J. Y., Environmental impacts of steel slag reused in road construction: a crystallographic and molecular (XANES) approach, Journal of Hazardous Materials 139(3), 537 to 542 (2007), doi 10.1016/j.jhazmat.2006.02.060 (abstract)
40 CFR 437.11, Effluent limitations (BPT), centralized waste treatment point source category, Subpart A metals treatment and recovery
40 CFR 423.19, Reporting and recordkeeping requirements, steam electric power generating point source category, Table 1 to paragraph (k)(2)(v), BAT treated pollutants in combustion residual leachate
ATSDR, Toxicological Profile for Vanadium (2012), section 6.4.2 water (read from the Internet Archive copy of the PDF)
Jalali F., Fakhar J., Zolfaghari A., Investigation on biosorption of V(III), Ti(IV), and U(VI) ions from a contaminated effluent by a newly isolated strain of Galdieria sulphuraria, Separation Science and Technology 54(13), 2222 to 2239 (2019), doi 10.1080/01496395.2018.1543323 (abstract)
Baes, C. F. and Mesmer, R. E., The Hydrolysis of Cations (Wiley, 1976), the vanadium sections (hydrolysis of vanadium(V) and vanadium(IV), the decavanadate polymerisation)

Identity

Name and symbol: Vanadium, V
Atomic number: 23 protons
Position: group 5 · period 4 · d-block · transition metal
CAS number: 7440-62-2

Atomic structure

Atomic mass: 50.9415 u
Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d³
[Ar] 4s²³d³
Electrons per shell: 2, 8, 11, 2
Valence electrons: 5 ns and (n-1)d

isotope	mass (u)	abundance
⁵⁰V	49.947 156(3)	0.2 %
⁵¹V	50.943 957(3)	99.7 %

natural isotopic composition, mole fraction

Physical properties

State at room temperature: Solid
Melting point: 2,183 K (1,909.85 °C)
Boiling point: 3,680 K (3,406.85 °C)
Density: 6 g/cm3
Appearance: blue-silver-grey metal
Thermal conductivity: 30.7 W/(m·K)
Electrical resistivity: 197 nΩ·m at 20 °C
Electrical conductivity: 5.08 MS/m
Crystal structure: body-centered cubic
Molar heat capacity: 24.89 J/(mol·K)

Chemical properties

Oxidation states: +5, +4, +3, +2
Electronegativity: 1.63 (Pauling Scale)
Ionisation energy: 6.746 eV
1st 650.9, 2nd 1,414, 3rd 2,830 kJ/mol
Electron affinity: 0.525 eV
Atomic radius: empirical 153, covalent 153, van der Waals 179 pm
Ionic radius: V²⁺ 79; V³⁺ 64; V⁴⁺ 58; V⁵⁺ 54 pm

Reactivity: A group 5 transition metal ([Ar] 3d3 4s2) with four accessible oxidation states (+2 to +5) and a passivating oxide film that makes the bulk metal corrosion resistant, though it oxidises readily when heated.
with water: Does not react; the metal resists salt water and is protected by its oxide layer.
with oxygen, air: Stable in air at room temperature behind a passivating oxide, but oxidises readily above about 660 C, ultimately to the pentoxide: $\ce{4 V + 5 O2 -> 2 V2O5}$
with acids: Resists dilute sulfuric and hydrochloric acid and alkalis; solutions of vanadium(V) are reduced stepwise by zinc in acid through the blue, green and lilac lower states.
with halogens: Forms twelve binary halides VXn with n from 2 to 5, all Lewis acidic and the vanadium(IV) and (V) ones especially so.

Typical compounds

V₂O₅ vanadium pentoxide the key industrial compound; contact process catalyst, ceramics
NH₄VO₃ ammonium metavanadate usual laboratory source of vanadium(V)
VCl₃ vanadium trichloride reduced with magnesium to high-purity metal
VOSO₄ vanadyl sulfate blue vanadium(IV) salt of the VO2+ ion
V₄C₃ vanadium carbide fine grains that strengthen vanadium steels

Occurrence, production and use

Crustal abundance: 1.20×102 milligrams per kilogram
Oceanic abundance: 2.5×10-3 milligrams per liter

Occurrence and sources

Vanadium is found in about 65 different minerals among which are carnotite, roscoelite, vanadinite, and patronite, important sources of the metal. Vanadium is also found in phosphate rock and certain iron ores, and is present in some crude oils in the form of organic complexes. It is also found in small percentages in meteorites.

Commercial production from petroleum ash holds promise as an important source of the element. High-purity ductile vanadium can be obtained by reduction of vanadium trichloride with magnesium or with magnesium-sodium mixtures.

Much of the vanadium metal being produced is now made by calcium reduction of V2O5 in a pressure vessel, an adaption of a process developed by McKechnie and Seybair.

vanadinite, carnotite, patronite, roscoelite about 65 vanadium minerals; vanadinite Pb5(VO4)3Cl was the mineral of the 1801 discovery
vanadiferous titaniferous magnetite, phosphate rock, uraniferous sandstone and siltstone host rocks with less than 2 percent vanadium; China, Russia, South Africa and Brazil produce from titaniferous magnetite processed for steel; world resources exceed 63 million tonnes
organic vanadium complexes crude oil, coal, oil shale and tar sands; petroleum residues, spent catalysts and utility ash are the secondary feed of United States producers

Extraction, production: Co product recovery from vanadiferous iron ore and residues
Most vanadium is recovered from slag made when vanadium bearing magnetite is smelted for steel, and from petroleum residues, spent catalysts and boiler ash, and sold as vanadium pentoxide or ferrovanadium (78 to 82 percent vanadium). World mine production about 100,000 tonnes of vanadium in 2024 (estimate); to convert V2O5 to vanadium content multiply by 0.56. The roast leach chemistry is not given by the source, so no equation is written.
Metal by calcium reduction of the pentoxide
$\ce{V2O5 + 5 Ca -> 2 V + 5 CaO}$
Balanced from the reactants and products stated by the sources (vanadium(V) oxide reduced with calcium in a pressure vessel, the McKechnie and Seybolt process). Ductile high purity vanadium is made instead by reducing vanadium trichloride with magnesium: $\ce{2 VCl3 + 3 Mg -> 2 V + 3 MgCl2}$ , likewise balanced from the stated reactants and products.

Uses

Vanadium is corrosion resistant and is sometimes used to make special tubes and pipes for the chemical industry. Vanadium also does not easily absorb neutrons and has some applications in the nuclear power industry. A thin layer of vanadium is used to bond titanium to steel.

Nearly 80% of the vanadium produced is used to make ferrovanadium or as an additive to steel. Ferrovanadium is a strong, shock resistant and corrosion resistant alloy of iron containing between 1% and 6% vanadium. Ferrovanadium and vanadium-steel alloys are used to make such things as axles, crankshafts and gears for cars, parts of jet engines, springs and cutting tools.

Vanadium pentoxide (V2O5) is perhaps vanadium's most useful compound. It is used as a mordant, a material which permanently fixes dyes to fabrics. Vanadium pentoxide is also used as a catalyst in certain chemical reactions and in the manufacture of ceramics. Vanadium pentoxide can also be mixed with gallium to form superconductive magnets.

Vanadium is used in producing rust resistant and high speed tool steels. It is an important carbide stabilizer in making steels.

About 80% of the vanadium now produced is used as ferrovanadium or as a steel additive. Vanadium foil is used as a bonding agent in cladding titanium to steel. Vanadium pentoxide is used in ceramics and as a catalyst.

It is also used to produce a superconductive magnet with a field of 175,000 gauss.

Steel: ferrovanadium and vanadium steel additive for high strength low alloy, tool and rust resistant steels; less than 1 percent vanadium makes steel shock and vibration resistant; aerospace titanium alloys, where vanadium has no substitute about 80 percent of vanadium produced is used as a steel additive (RSC); metallurgical use was more than 90 percent of United States reported consumption in 2024 (USGS)
Chemicals: vanadium pentoxide catalyst for oxidising sulphur dioxide to sulphur trioxide in sulphuric acid plants: commercial catalysts contain 4 to 9 percent V2O5 with alkali sulphate promoters and vanadium is used almost exclusively (LVIC-AAF BREF); catalysts for maleic anhydride, the main non metallurgical use named by USGS; spent vanadium catalysts as a waste stream of acid plants
Batteries and energy: vanadium redox flow batteries for grid scale storage, growing but limited by feedstock cost; vanadium alloys in nuclear reactors for their low neutron absorption
Glass and ceramics: vanadium(V) oxide as a pigment for ceramics and glass and in superconducting magnets
Mining: vanadium is one of the metalliferous ores grouped with iron ore in the MWEI BREF and is listed among the substances discharged from ore processing and extractive waste facilities

Safety, toxicity: Vanadium and its compounds are toxic and should be handled with care. The maximum allowable concentration of V2O5 dust in air is about 0.05 (8-hour time-weighted average - 40-hour week).

Discovery and name

Discovered by: Andrés Manuel del Río
Discovered: 1801
First isolated: Henry Enfield Roscoe
Named by: Nils Gabriel Sefström
Origin of the name: after Vanadís, the Norse goddess of beauty, because of the wide range of its compounds' colors

Pure vanadium is a bright white metal, and is soft and ductile. It has good corrosion resistance to alkalis, sulfuric and hydrochloric acid, and salt water, but the metal oxidizes readily above 660°C.

The metal has good structural strength and a low fission neutron cross section, making it useful in nuclear applications.

Conventions

Valence electrons are counted by the usual convention: the outer shell for s- and p-block elements, ns and (n-1)d for the d-block, ns, (n-1)d and (n-2)f for the f-block. Lanthanides and actinides are placed in the f-block with no group number. Electrical conductivity is the reciprocal of the printed resistivity. Ionic radii are Shannon effective radii, six-coordinate unless noted. Where a field reads “not in sources” the value was not found; it is a gap, not a zero. Regulatory limits are the published values and change often, so check the standard in force at your site and the numbers written into your own permit before you design to them.

Data

Element records, isotopes, radii and the descriptive text come from PubChem (NCBI), the Los Alamos National Laboratory periodic table, IUPAC CIAAW and the IAEA Atomic Mass Data Center. Appearance, thermal conductivity, electrical resistivity, crystal structure, discovery and the origin of each name come from Wikipedia and Periodic-Table-JSON, used under CC BY-SA 4.0. Hazard classifications come from the ECHA C&L inventory via PubChem. Ionic radii follow R. D. Shannon (1976). The water chapters cite their own sources at the foot of each entry, and are written to the level of Snoeyink and Jenkins, Stumm and Morgan, MWH's Water Treatment and Metcalf and Eddy.