Millon's base

Structural formula
General
Surname	Millon's base
Molecular formula	(Hg 2 N) OH • 2 H 2 O
Brief description	pale yellow cubic crystals
External identifiers / databases
CAS number 12529-66-7 Wikidata Q1935598
properties
Molar mass	468.25 g mol −1
Physical state	firmly
solubility	soluble in water
safety instructions
GHS hazard labeling no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

The Millon Base is a light yellow nitrogen - mercury compound of composition (Hg ₂ N) OH · 2 H ₂ O. It is after its discoverer Eugène Millon named.

Extraction and presentation

Millon's base or its chloride is produced by boiling the " infusible precipitate ":

${\displaystyle \mathrm {2\ Hg(NH_{2})Cl\longrightarrow [Hg_{2}N]Cl+NH_{4}Cl} }$

The base can also be obtained from mercury (II) oxide and aqueous ammonia.

${\displaystyle \mathrm {2\ HgO+NH_{3}\longrightarrow [Hg_{2}N]OH\cdot 2H_{2}O{\xrightarrow {110\ ^{\circ }C}}[Hg_{2}N]OH\cdot H_{2}O} }$

The bromide can be obtained by reacting mercury (II) bromide with ammonia.

${\displaystyle \mathrm {2\ HgBr_{2}+4\ NH_{3}\longrightarrow [Hg_{2}N]Br+3\ NH_{4}Br} }$

properties

Millon's base forms cubic crystals . The cations [Hg ₂ N] ⁺ form a space structure similar to the cristobalite structure (modification of silicon dioxide , SiO ₂ ), the cavities of which are occupied by hydroxide ions and water molecules. Each mercury atom is linearly connected to two nitrogen atoms, each nitrogen atom is tetrahedrally surrounded by 4 mercury atoms . Millon's base and its salts thus represent ion exchangers similar to zeolites .

Many other salts of Millon's base are known, for example bromide, orange-brown iodide, yellowish-white, water-insoluble nitrate and perchlorate.

Due to the intense red-brown color of the iodide of Millon's base, ammonia can also be detected in traces with the help of Neßler's reagent .

The base itself, as well as its salts, are not very stable and can explode on impact or blow, especially when dry. The base can be reversibly converted into the brown hydrates (Hg ₂ N) OH · H ₂ O and (Hg ₂ N) OH · 1/2 H ₂ O by careful heating . Complete removal of the water of hydration creates the "anhydride of Millon's base", (Hg ₂ N) OH.

Individual evidence

1. ↑ ^{a b c d e} Wissenschaft-Online-Lexika: Entry on "Millon's Base" in the Lexikon der Chemie. Retrieved August 4, 2010.
2. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
3. ↑ ^{a b} Entry on Millon's Base. In: Römpp Online . Georg Thieme Verlag, accessed on January 19, 2012.
4. ↑ Georg Brauer (Ed.), With the collaboration of Marianne Baudler a . a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume II, Ferdinand Enke, Stuttgart 1978, ISBN 3-432-87813-3 , p. 1059.
5. ^ WN Lipscomb: The structure of Millon's base and its salts . In: Acta Crystallographica . tape 4 , no. 2 , March 1951, p. 156-158 , doi : 10.1107 / S0365110X51000453 .
6. ↑ Cotton-Wilkinson, Inorganic Chemistry, 3rd Edition, Verlag Chemie 1974 ISBN 3-527-25503-6
7. ↑ S. Ebel, HJ Roth (editor): Lexicon of Pharmacy . Georg Thieme Verlag, 1987, ISBN 3-13-672201-9 , p. 440.
8. ^ Arnold Frederik Holleman, Egon Wiberg, Nils Wiberg: Textbook of Inorganic Chemistry . 81. – 90., Care. rev., verb. and strong exp. Edition. de Gruyter , Berlin 1976, ISBN 3-11-005962-2 .