Search results
Results From The WOW.Com Content Network
Dissolution of vanadium pentoxide in strongly basic aqueous solution gives the colourless VO 3− 4 ion. On acidification, this solution's colour gradually darkens through orange to red at around pH 7. Brown hydrated V2O5 precipitates around pH 2, redissolving to form a light yellow solution containing the [VO 2 (H 2 O) 4] + ion. The number and ...
Complexes of vanadium(II) and (III) are relatively exchange inert and reducing. Those of V(IV) and V(V) are oxidants. Vanadium ion is rather large and some complexes achieve coordination numbers greater than 6, as is the case in [V(CN) 7] 4−. Oxovanadium(V) also forms 7 coordinate coordination complexes with tetradentate ligands and peroxides ...
The name was based on the wide range of colors found in vanadium compounds. Del Río's lead mineral was ultimately named vanadinite for its vanadium content. In 1867, Henry Enfield Roscoe obtained the pure element. Vanadium occurs naturally in about 65 minerals and fossil fuel deposits. It is produced in China and Russia from steel smelter slag.
The color of chemicals is a physical property of chemicals that in most cases comes from the excitation of electrons due to an absorption of energy performed by the chemical. The study of chemical structure by means of energy absorption and release is generally referred to as spectroscopy .
Structure of vanadyl acetylacetonate Cavansite, a mineral containing the vanadyl cation that illustrates its characteristic color. The vanadyl or oxovanadium(IV) cation, VO 2+, [1] is a functional group that is common in the coordination chemistry of vanadium. Complexes containing this functional group are characteristically blue and paramagnetic.
The compound is prepared by the addition of ammonium salts to solutions of vanadate ions, generated by dissolution of V 2 O 5 in basic aqueous solutions, such as hot sodium carbonate. The compound precipitates as a colourless solid. [3] [4] This precipitation step can be slow.
Vanadyl perchlorate or vanadyl triperchlorate is a golden yellow coloured liquid or crystalline compound of vanadium, oxygen and perchlorate group. The substance consists of molecules covalently bound and is quite volatile; it ignites organic solvents on contact and explodes at temperatures above 80 °C.
When the pH of the solution is increased by adding an alkaline solution to it, the extent of hydrolysis increases. Measurements of pH or colour change are used to derive the equilibrium constant for the reaction. Further hydrolysis may occur, producing dimeric, trimeric or polymeric species containing hydroxy- or oxy- groups.