Manganese ferrocyanide

Manganese ferrocyanide, Mn2Fe(CN)6, is a white substance, which is turned green by chlorine water and oxidised to brown ferncyamde by bromine water.4... 

The acid filtrate is treated with excess of ammonium chloride and with ammonia to precipitate the ferric oxide and any alumina, the precipitate being tested for the latter in the usual way. The filtrate is divided into three parts one is acidified with acetic acid and tested for copper with ferrocyanide in another the manganese (if present) is precipitated with ammonium sulphide, lime and magnesia being then tested for in the third sulphates are tested for with barium chloride. Manganese is best sought in a separate portion of the substance by the well-known dry reaction. 

The most commonly used synthesis of [l,2,3]triazolo[l,5-fl]pyridines remains that from the hydrazones of 2-p) idyl-carboxaldehydes or -ketones by oxidation. Some hydrazones give triazolop) dines when boiled in methanol in the presence of air, but all other reported cases require an added oxidant. The use of the most common oxidants illustrates the versatility of the synthesis. Nickel peroxide, potassium ferrocyanide and bicarbonate, air and a copper-II salt, manganese dioxide or (diacetoxyiodo)benzene have been used (02AHC1). An alternative route from tosylhydrazones of 2-pyridyl-carboxaldehydes or ketones by treatment with base, usually morpholine, has been used for high yields of sensitive materials (02AHC1). 

Iron, uranium, chromium and manganese form colored alizarin lakes and, therefore, interfere in the Al-alizarin test. In some cases, the interference can be eliminated by precipitation as ferrocyanides. Thus, when the precipitation is carried out on filter paper impregnated with potassium ferrocyanide, the aluminum salt diffuses through the capillaries to the water zone encircling the fleck of precipitate and can be detected there by the alizarin reaction. 

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