Fiery mercury

Structural formula
General
Surname	Fiery mercury
other names	Mercury (II) fulminate; Mercury fulminate; Mercury difulminate; Mercury cyanate;
Molecular formula	Hg (CNO) 2
Brief description	white-gray powder
External identifiers / databases
EC number	211-057-8
ECHA InfoCard	100.010.053
PubChem	11022444
Wikidata	Q309033
properties
Molar mass	284.62 g mol −1
Physical state	firmly
density	4.42 g cm −3
Melting point	explodes above 160–180 ° C
solubility	slightly soluble in water (100 mg l −1 at 15.5 ° C)
safety instructions
H and P phrases	H: 200-331-311-301-373-410
	P: ?
MAK	0.1 mg m −3
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Mercury fulminate (chemical: mercury (II) fulminate ) is the mercury salt of fulminate . In its purest form, it forms colorless crystals. Fumed mercury is poisonous and decomposes even with low mechanical or thermal stress.

history

The fiery mercury was probably isolated for the first time by Kunkel von Löwenstern and other alchemists at the end of the 17th century . The production from mercury , ethanol and nitric acid was first described in 1799 by the Englishman E. Howard .

Due to its pronounced initiating ability, fumed mercury was the most widespread initial explosive at the time. It was used in primers and detonators . Alfred Nobel used fumed mercury in detonators to ignite dynamite . It was only this relatively safe ignition method that established the broad success of dynamite explosives. In the German Empire alone, the annual production of fumed mercury at the beginning of the 20th century was around 100 t.

In the meantime, however, fiery mercury has been replaced by other substances, e.g. B. lead azide .

Extraction and presentation

Mercury fulminate is produced by reacting elemental mercury or mercury (II) oxide with concentrated nitric acid in the presence of ethanol. The synthesis of large amounts of mercury fulminate requires strict safety precautions and may only be carried out by trained specialists.

The method for silver fulminate described in 1901 by the Italian Angelico can be used to represent small quantities . Instead of ethanol, the reaction takes place here with aqueous solutions of malonic acid and sodium nitrite .

Impurities caused by by-products can be removed by recrystallizing one or more times from ammonia solution. Fiery mercury crystallizes from aqueous solutions as hemihydrate Hg (CNO) ₂ · ½ H ₂ O.

properties

Physical Properties

Mercury fulminate is readily soluble in hot water , ethanol and nitric acid , but only poorly soluble in cold water.

Chemical properties

Mercury fulminate decomposes explosively even under low mechanical or thermal stress. This creates elemental mercury , nitrogen and carbon monoxide :

{\ displaystyle \ mathrm {ONC {-} Hg {-} CNO \ longrightarrow Hg + N_ {2} +2 \ CO}}

Here the decay can easily turn into a detonation (v = 5000 m / s) by damming or igniting larger quantities .

Since the explosion creates a cloud of atomic, toxic mercury vapor, it is no longer used as an explosive today.

Crystal structure

Investigations into the crystal lattice of fumed mercury were carried out as early as the 1930s. It was not until 2007 that clear results were achieved. Flash mercury is therefore orthorhombic . The Hg atoms and the two surrounding C atoms are - as already suspected - arranged linearly, so that the molecular, stretched arrangement of ONC-Hg-CNO is confirmed.

contaminated mercury fulminate
Comparison picture of the quality extremes
pure mercury fulminate

safety instructions

Mercury fulminate is an initial explosive and therefore particularly explosive. An explosion can occur due to ignition sources or mechanical effects such as friction or impact, but also due to the effects of radiation , drying or contact with other chemical compounds such as sulfuric acid .

Mercury fulminate is poisonous and dangerous for the environment; It represents a particularly high hazard potential for aquatic organisms. Stored under water, it is not explosive and chemically stable.

Individual evidence

↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Properties of the Elements and Inorganic Compounds, pp. 4-76.
↑ ^a ^b ^c ^d ^e ^f Entry on mercury fulminate in the GESTIS substance database of the IFA , accessed on February 17, 2017(JavaScript required) .
↑ Entry on Mercury difulminate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
^ Wissenschaft-Online-Lexika: Entry on "Mercury fulminate" in the Lexikon der Chemie , accessed on July 11, 2013.
↑ Beck, Evers, Göbel, Oehlinger, Klapötke: The Crystal and Molecular Structure of Mercury Fulminate (fiery mercury) . Z. anorg. allg. Chem. 2007, Vol. 633, No. 9, pp. 1417-1422.

literature

R. Knoll: The fiery mercury and other explosives. , Survival Press, Radolfz., November 2001, ISBN 3-8311-2876-6
A. Stettbacher: The guns and explosives. 2nd edition, Leipzig, 1933.

[crc-1] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Properties of the Elements and Inorganic Compounds, pp. 4-76.

[GESTIS-2] ↑ ^a ^b ^c ^d ^e ^f Entry on mercury fulminate in the GESTIS substance database of the IFA , accessed on February 17, 2017(JavaScript required) .

[CLP_100.010.053-3] Entry on Mercury difulminate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[4] Wissenschaft-Online-Lexika: Entry on "Mercury fulminate" in the Lexikon der Chemie , accessed on July 11, 2013.

[5] Beck, Evers, Göbel, Oehlinger, Klapötke: The Crystal and Molecular Structure of Mercury Fulminate (fiery mercury) . Z. anorg. allg. Chem. 2007, Vol. 633, No. 9, pp. 1417-1422.