Molybdenum blue

Colloidal solution of molybdenum blue

Molybdenum blue (also mineral indigo ) is a name for molybdenum oxide hydroxides with the general composition Mo _x O _y (OH) _z . The oxidation number of molybdenum is between 5 and 6. For example, molybdenum has the oxidation number 5 in the Mo ₂ O ₄ (OH) ₂ compound, the mean oxidation number 5.5 in the Mo ₄ O ₁₀ (OH) ₂ compound and 5.5 in Mo ₈ O ₁₅ (OH) _{16 has} the mean oxidation number 5.75. These three connections were first presented and characterized by Oskar Glemser in 1951 . There are crystalline and amorphous modifications of molybdenum blue.

Manufacturing

Molybdenum blue is obtained as a colloidal solution after the reduction of acidified molybdate solutions with a reducing agent such as tin (II) ions, zinc , sulfur dioxide , hydrazine or hydrogen sulfide . Production from molybdenum (VI) oxide by reduction with hydrogen or with lithium aluminum hydride is also possible.

${\displaystyle \mathrm {4\ MoO_{3}+H_{2}\longrightarrow Mo_{4}O_{10}(OH)_{2}} }$

Applications

The formation of molybdenum blue is important in analytical chemistry for the detection of molybdenum and phosphates .

Individual evidence

1. ^ Oskar Glemser , Gertrud Lutz: About molybdenum blue . In: Journal of Inorganic and General Chemistry . tape 264 , no. 1 , 1951, p. 17-33 , doi : 10.1002 / zaac.19512640104 .
2. ↑ Cotton / Wilkinson: Inorganische Chemie , Verlag Chemie, Weinheim 1967, p. 873.
3. ↑ ^{a b} Heinrich Remy : Textbook of Inorganic Chemistry Volume II , Academic Publishing Company Geest & Portig, Leipzig 1961, pp. 205–206.