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V2O5 is a binary transitional metal oxide with the highest oxidation state (+V) among vanadium oxides. At room temperature, this oxide is an odorless solid crystalline powder whose color varies from pale yellow to dark orange depending on its state of division (Figure 1)[1, 2]. V2O5 is hazardous for health and environment, but it has properties that are used in many industry applications, such as a cathode in lithium-ion batteries[2, 3], a component in special glasses[4], and a catalyst in the production of various acids such as sulfuric[1, 5]. And although this is only a part of all possible applications, vanadium pentoxide has found the greatest distribution (about 85% of all world vanadium) in the production of springs and cutting-tool steels, where it is mixed with Fe2O3 and Al to increase their toughening[1].


Vanadium pentoxide can be obtained in several ways, for example, by heating metallic vanadium in oxygen under pressure as shown in following equation:

4 V + 5 O2 → V2O5

However, this method does not produce the purest vanadium pentoxide, since in addition to V2O5, other vanadium oxides are formed during this heating, which are difficult to separate from each other[6].

Another method is to calcinate other vanadium oxides such as VO, V2O3 and VO2 in oxygen as shown in the example below[7]:

4 VO2 + O2 → 2 V2O5

The purest V2O5 is obtained by a multi-step reaction. First, vanadium slag is mixed with NaCl and roasted, which leads to the oxidation of vanadium to form V(V) and the formation of sodium vanadate. Further, with the help of sulfuric acid, the pH is lowered, which leads to the formation of sodium polyvanadate 6 Na4H2V10O28. An increase in temperature triggers the hydrolysis of sodium polyvanadate, which leads to the precipitation of a phase called "red cake" (Figure 2.) due to the characteristic reddish color:

6 Na4H2V10O28 + 7 H2SO4 + (n+13) H2O 5 Na2V12O31 · n H2O + 7 Na2SO4+13 H2O

Next, the "red cake" is dissolved in sodium hydroxide, which leads to an increase in pH, and NH4Cl is added, which leads to the precipitation of ammonium metavanadate:

VO3- + NH4+ NH4VO3

Finally, the ammonium metavanadate is calcined, resulting in V2O5 with a purity of about 98.5%[9, 10]:

2 NH4VO3 → V2O5 + NH3 + H2O


Vanadium pentoxide occurs overwhelmingly in an orthorhombic crystal system[11-13], however, there are also reports of the existence of V2O5 with a monoclinic system[14]. The difference between the methods for producing an orthorhombic and monoclinic structure is that a much higher pressure (about 4-6 GPa) is required to obtain a monoclinic structure, which allows the orthorhombic structure to be reformed into a denser form. Below are images of V2O5 structures in the orthorhombic system (Figs. 3 and 4) and in the monoclinic system (Figs. 5 and 6). As can be seen from these figures, the difference between these systems, in addition to the unit cell parameters and crystal symmetry, lies in the fact that the polyhedra in the orthorhombic system have the shape of a square pyramid, and in the monoclinic system they have the shape of an octahedron. However, it should be noted that in the ICSD data, from which the pictures below were made, there is also a sixth V-O bond with a bond length significantly longer than the others (2.81 Å vs. 2.02 Å), making the polyhedra octahedral. Earlier studies did indicate the presence of this bond in the structure[11], however, later studies have shown that this bond is really a weak interaction, and polyhedra are in fact square pyramids with common corners and edges[16]. Thus, if we consider the orthorhombic structure from a larger distance (Fig. 4), we see that it forms two-dimensional nets.

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Figure 3. Close-up structure of orthorhombic V2O5 (Data from ICSD, visualized with VESTA. Figures: Nikita Jamkin).

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Figure 4. Distant orthorhombic V2O5 structure (Data from ICSD, visualized with VESTA. Figures: Nikita Jamkin).

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Figure 5. Close-up structure of monoclinic V2O5 (Data from ICSD, visualized with VESTA. Figures: Nikita Jamkin).

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Figure 6. Distant structure of monoclinic V2O5 (Data from ICSD, visualized with VESTA. Figures: Nikita Jamkin).


V2O5 is a diamagnetic compound and experiences rather weak repulsive forces in the presence of an external magnetic field. Can be used as an n-type semiconductor, i.e. with electrons as charge carriers because of its relatively small indirect band gap of approximately 2.3 eV[17]. Moreover, due to its high oxidation state, it is an amphoteric compound and, depending on the medium, behaves like a base or an acid[18]. It is insoluble in ethanol, but unlike most metal oxides it is slightly soluble in water and highly soluble in bases and acids[6, 8]. Below are the XRD patterns for both V2O5 crystal systems (Figure 7) and band structure for orthorhombic V2O5 (Figure 8).

Figure 7. XRD patterns for orthorhombic (left, license: CC BY)[19] and monoclinic (right; calculated data from ICSD, Figure: Nikita Jamkin) V2O5 systems.

Figure 8. V2Oband structure (License: CC BY)[17].


  1. Housecroft, C.E. and Sharpe, A.G. "Chapter 21: d-Block metal chemistry: the first row metals", Inorganic Chemistry, 4th Edition. Pearson Education Limited. 2012, pp. 717–728. ISBN 978-0-273-74275-3.
  2. Szabolcs, B. A review of the growth of V2O5 films from 1885 to 2010. Thin Solid Films. 519, 2011, pp. 1761–1771. DOI:10.1016/j.tsf.2010.11.001.
  3. Yuxin, T. et al. Vanadium pentoxide cathode materials for high-performance lithium-ion batteries enabled by a hierarchical nanoflower structure via an electrochemical process. Journal of Materials Chemistry A. 1, 2013, pp. 82–88. DOI:10.1039/C2TA00351A.
  4. Nishida, T. et al. Characterization and Conduction Mechanism of Highly Conductive Vanadate Glass. Croat. Chem. Acta. 88, 2015, pp. 427–435. DOI:10.5562/cca2760.
  5. Barelko, V.V. et al. Glass-Fiber Woven Catalysts as Alternative Catalytic Materials for Various Industries. A Review. Russian Journal of Physical Chemistry. 11, 2017, pp. 606–617. DOI:10.1134/S1990793117040030.
  6. "The Vivid Element Vanadium." ChemTalk.
  7. "Vanadium(V) oxide." ChemEurope, 23.2.2023.
  8. "Vanadium(V) oxide." Wikipedia, Wikimedia Foundation, 23.2.2023.
  9. Zhang, Y-M. et al. The technology of extracting vanadium from coal in China: History, current status and future prospects. Hydrometallurgy. 109, 2011, pp. 116–124. DOI:10.1016/j.hydromet.2011.06.002.
  10. Hao, P. A literature review on leaching and recovery of vanadium. Journal of Environmental Chemical Engineering. 7, 2019, pp. 103313. DOI:10.1016/j.jece.2019.103313.
  11. Bachmann, H.G. et al. The crystal structure of vanadium pentoxide. Zeitschrift für Kristallographie. 115, 1961, pp. 110–131. DOI:10.1524/zkri.1961.115.1-2.110.
  12. Shklover, V. & Haibach, T. Crystal Structure of the Product of Mg2+ Insertion into V2O5 Single Crystals. Journal of Solid State Chemistry. 123, 1996, pp. 317–323. DOI:10.1006/JSSC.1996.0186.
  13. Sung-Chul, L. et al. Unraveling the Magnesium-Ion Intercalation Mechanism in Vanadium Pentoxide in a Wet Organic Electrolyte by Structural Determination. Inorganic Chemistry. 56, 2017, pp. 7668–7678. DOI:10.1021/acs.inorgchem.7b00204.
  14. Balog, P. et al. V2O5 phase diagram revisited at high pressures and high temperatures. Journal of Alloys and Compounds. 429, 2007, pp. 87–98. DOI:10.1016/j.jallcom.2006.04.042.
  15. "Vanadium pentaoxide." PubChem Identifier: CID 14814.
  16. Enjalbert, R. & Galy, J. A refinement of the Structure of V2O5. Acta Cryst. C42, 1986, pp. 1467-1469. DOI:10.1107/S0108270186091825.
  17. Armaković, S. et al. Photocatalytic Activity of the V2O5 Catalyst toward Selected Pharmaceuticals and Their Mixture: Influence of the Molecular Structure on the Efficiency of the Process. Molecules. 28, 2023, pp. 655. DOI:10.3390/molecules28020655.
  18. Zhongqiu, T. et al. Recent advances in multifunctional electrochromic energy storage devices and photoelectrochromic devices. Science China Chemistry. 60, 2017, pp. 13–37. DOI:10.1007/s11426-016-0283-0.
  19. Wei-Sheng, C. et atl. Recycling Vanadium and Proton-Exchange Membranes from Waste Vanadium Flow Batteries through Ion Exchange and Recast Methods. Materials. 15, 2022, pp. 3749. DOI:10.3390/ma15113749.

Изображение молекулярной модели

Figure 1. V2O5 powder (License: Public Domain)[8].


Figure 2. "Red cake" (License: Public Domain)[8].

                 Properties of V2O5[15]
Molar mass181.88 g/mol
Density3.35 g/cm3
Water solubility0.7 g/L (20 °C)
Melting point681 °C
Boiling point1750 °C (decomposes)
Magnetic susceptibility+128.0·10−6 cm3/mol (diamagnetic)


        Structural properties of V2O5[11, 14]
Crystal systemOrthorhombicMonoclinic
ICSD No.15798156052
Space group

Pmmn (No. 59)

C2/c (No. 15)
Unit cell dimensions

a=11.510 Å, b=4.369 Å,  c=3.563 Å

α=90°, β=90°, γ=90°

a=11.972 Å, b=4.702 Å, c=5.325 Å

α=90°, β=104.41°, γ=90°

Unit cell volume179 Å3300 Å3
Formula units per unit cell24