HMX
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HMX, also called octogen or cyclotetramethylene-tetranitramine, is a powerful, and relatively insensitive, nitroamine high explosive, chemically related to RDX.
History
First made in 1930, it is used almost exclusively in military applications including as the detonators in nuclear weapons, in the form of plastic bonded explosive, and as a solid rocket propellant.
Its molecule is an eight-membered ring made of four carbon and four nitrogen atoms, with a nitro group hanging off of each nitrogen atom. Because of its high molecular weight, it is one of the most powerful chemical explosives manufactured, although a number of newer ones, including HNIW and octanitrocubane are more powerful and less sensitive.
There are other names occasionally used for it — octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine, tetrahexamine tetranitramine, or cyclotetramethylene tetranitramine. It may be produced by nitration of hexamine in the presence of acetic anhydride, paraformaldehyde and ammonium nitrate. RDX produced using the Bachmann Process usually contains 8-10% HMX.
Like RDX, it has various mistranslations of its acronym including High Melting eXplosive, Her Majesty's eXplosive or even High velocity Military eXplosive. In fact the acronym simply means 'High Molecular weight rdX'.
Properties
The velocity of detonation of HMX at a density of 1.90 g/cm3 is 9,100 meters per second.
Its CAS Number is 2691-41-0. The chemical formula is C4H8N8O8. It is a colorless solid with a melting point of 276 to 286 °C, although it usually decomposes at 280 °C. Its molecular weight is 296.20 and its practical maximum density is 1.91 g/cm3, with a theoretical maximum crystal density of 1.96. It is slightly soluble in water.
HMX is used in melt-castable explosives when mixed with TNT, which as a class are referred to as "octols." Octol itself is 75% HMX, 25% TNT.
References:
- Cooper, Paul W., Explosives Engineering, New York: Wiley-VCH, 1996. ISBN 0-471-18636-8
- Urbanski, Tadeusz. Chemistry and Technology of Explosives. Vol. III., Warszawa: Polish Scientific Publishers, 1967de:Oktogen