How many chemical bonds are there in C5H12


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n-Pentane is a colorless liquid with the empirical formula C.5H12 and is one of the alkanes. The name “pentane” is derived from the five bonded carbon atoms (penta, Greek: “five”). It is the linear representative of the three structural isomers of pentanes (n-Pentane, isopentane and neopentane).

Extraction and presentation

Pentanes occur in natural gases, cracked gases and gasoline and can be obtained from them by distillation. They are part of the petroleum ether.


Pentane is a colorless liquid that smells like petrol. It is non-polar and therefore hardly soluble in water, for example, but can be mixed with most organic solvents. The solubility in water is 40 mg / l (20 ° C).

The compound forms azeotropic mixtures with a number of other solvents. The azeotropic compositions and boiling points can be found in the following table. No azeotropes are made with cyclohexane, n-Hexane, n-Heptane, toluene, benzene, n-Propanol, n-Butanol, i-Butanol, 2-butanol, chloroform, THF and acetic acid are formed.[5]

The extremely flammable liquid is very volatile and evaporates at room temperature. This creates explosive gas mixtures with the air (see experiments with light petrol). The flash point of n-Pentane is -49 ° C, the ignition temperature is 309 ° C. The vapors are heavier than air and spread on the ground. Inhaling the vapors has an anesthetic effect in higher concentrations; dizziness, drowsiness, headache, nausea and cardiac arrhythmias can occur.


Today it is often used as a CFC-free refrigerant (R601) in refrigerators and air conditioning systems, as a solvent and for foaming rigid polyurethane foams, phenolic resin and polystyrene.

Individual evidence

  1. 1,01,11,21,31,41,51,61,7Entry to CAS no. 109-66-0 in the GESTIS substance database of the IFA, accessed on January 13, 2008 (JavaScript required).
  2. ↑ Thieme Chemistry (ed.): RÖMPP Online - Version 3.5. Georg Thieme Verlag KG, Stuttgart 2009.
  3. 3,03,1Entry from the CLP regulation too CAS no. 109-66-0 in the GESTIS substance database of the IFA (JavaScript required)
  4. ↑ Since December 1, 2012, only GHS hazardous substance labeling has been permitted for substances. The R-phrases of this substance may still be used to classify preparations until June 1, 2015, after which the EU hazardous substance labeling is of purely historical interest.
  5. 5,05,1IN THE. Smallwood: Handbook of organic solvent properties, Arnold London 1996, ISBN 0 340 64578 4, pp. 12-13.