Vanadium(V) oxide

Vanadium(V) oxide

Names
IUPAC name Divanadium pentaoxide
Other names Vanadium pentoxide Vanadic anhydride Divanadium pentoxide
Identifiers
CAS Number	1314-62-1 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:30045 Y
ChemSpider	14130 Y
ECHA InfoCard	100.013.855
EC Number	215-239-8
KEGG	C19308 N
PubChem CID	14814
RTECS number	YW2450000
UN number	2862
InChI InChI=1S/5O.2V Y Key: GNTDGMZSJNCJKK-UHFFFAOYSA-N Y InChI=1/5O.2V/rO5V2/c1-6(2)5-7(3)4 Key: GNTDGMZSJNCJKK-HHIHJEONAP
SMILES O=[V](=O)O[V](=O)=O
Properties
Chemical formula	V2O5
Molar mass	181.8800 g/mol
Appearance	Yellow solid
Density	3.357 g/cm3
Melting point	690 °C (1,274 °F; 963 K)
Boiling point	1,750 °C (3,180 °F; 2,020 K) (decomposes)
Solubility in water	0.8 g/L (20 °C)
Magnetic susceptibility (χ)	+128.0·10−6 cm3/mol
Structure
Crystal structure	Orthorhombic
Space group	Pmmn, No. 59
Lattice constant	a = 1151 pm, b = 355.9 pm, c = 437.1 pm
Coordination geometry	Distorted trigonal bipyramidal (V)
Hazards
Safety data sheet	ICSC 0596
GHS pictograms
GHS signal word	DANGER
GHS hazard statements	H341, H361, H372, H332, H302, H335, H411
EU classification (DSD)	Muta. Cat. 3 Repr. Cat. 3 Toxic (T) Harmful (Xn) Irritant (Xi) Dangerous for the environment (N)
R-phrases	R20/22, R37, R48/23, R51/53, R63, R68
S-phrases	(S1/2), S36/37, S38, S45, S61
NFPA 704	0 3 0
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	10 mg/kg (rat, oral) 23 mg/kg (mouse, oral)
LCLo (lowest published)	500 mg/m3 (cat, 23 min) 70 mg/m3 (rat, 2 hr)
US health exposure limits (NIOSH):
PEL (Permissible)	C 0.5 mg V2O5/m3 (resp) (solid) C 0.1 mg V2O5/m3 (fume)
Related compounds
Other anions	Vanadium oxytrichloride
Other cations	Niobium(V) oxide Tantalum(V) oxide
Related vanadium oxides	Vanadium(II) oxide Vanadium(III) oxide Vanadium(IV) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

C 0.1 mg V₂O₅/m³ (fume)

Vanadium(V) oxide (vanadia) is the inorganic compound with the formula V₂O₅. Commonly known as vanadium pentoxide, it is a brown/yellow solid, although when freshly precipitated from aqueous solution, its colour is deep orange. Because of its high oxidation state, it is both an amphoteric oxide and an oxidizing agent. From the industrial perspective, it is the most important compound of vanadium, being principal precursor to alloys of vanadium and is a widely used industrial catalyst.

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.

Upon heating, it reversibly loses oxygen, successively forming V₂O₄, V₂O₃, VO, and metallic vanadium.

Unlike most metal oxides, it dissolves slightly in water to give a pale yellow, acidic solution. When this compound is formed by V₂O₅ it is an amphoteric oxide. Thus V₂O₅ reacts with strong non-reducing acids to form solutions containing the pale yellow salts containing dioxovanadium(V) centers:

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⁻ (decavanadate) predominate.