Laboratory Methods of Inorganic Chemistry, 2nd English Ed. 1928

162 SUBSTITUTED AMMONIUM COMPOUNDS.

134. Millon's Base.
     Millon's base, Hg 2 NOH. 2 H 2 O, is formed by the action of mercuric oxide
     upon an ammonia solution. Since, by merely heating, this compound is
     changed first to the monohydrate and then to dimercuriammonium hydrox-
     ide, Hg 2 NOH, it follows that in Millon's base itself the mercury is probably
     united to the nitrogen atom, as is unquestionably the case in the dehydration
     product. Whether the water is present in the compound as water of crystalli-
     zation, or whether it is combined by atomic valences, has not been established.
     In the latter case Millon's base would be regarded as dihydroxydimercuri-
     ammonium hydroxide (I) and its first dehydration product as oxydimercuri-
     ammonium hydroxide (II);

HOHg N / Hg\

;NH 2 OH (I) O' ,NH 2 OH (II).

The ability of mercury to replace hydrogen in certain compounds, with the
formation of substances like the above, which are stable in presence of water,
is also apparent in several series of mercury organic compounds.

Treat a solution of 25 g. mercuric chloride in 200 c.c. of water

at 70° with a solution of 7.5 g. sodium hydroxide in 20 c.c'water,

wash the resulting precipitate several times by decantation,

collect it on a suction filter and wash it further with water. Mean-

while prepare a carbonate-free solution of ammonia by distilling

a mixture of 150 g. concentrated ammonia with 20 g. of lime, first

placing 100 c.c. of cold water in the receiver. Introduce the

moist mercuric oxide into this ammonia solution and allow the

mixture to stand with frequent shaking for a day or two in

the dark. Collect the product on a suction filter, wash it with

water, alcohol and finally with ether, and dry it at the temperature

of the laboratory.

Salts of Millon's Base.

When solutions of ordinary salts are treated with Millon's base, salts of the

latter, which are very difficultly soluble, and free metal hydroxide, are formed.

Shake a little of Millon's base with a dilute solution of potassium

iodide. The solution becomes alkaline, and the brown residue is,

in all probability, identical with the well-known precipitate

obtained in the test for ammonia with Nessler's reagent. Filter

the solution through a double filter of hardened paper, and clarify

the turbid filtrate by shaking it with pieces of torn filter paper and