As a chemical expert with a deep understanding of organic chemistry and nomenclature, I can provide a detailed explanation on the topic of ethene and ethylene.

Ethene and ethylene are indeed the same chemical substance. They refer to the same molecule, which is the simplest alkene, with the chemical formula C2H4. This molecule consists of two carbon atoms double-bonded to each other and each carbon atom is also bonded to two hydrogen atoms. The double bond between the carbon atoms is what makes it an alkene, which is a class of hydrocarbons.

The confusion between the terms "ethene" and "ethylene" arises from the historical usage and the evolution of chemical nomenclature. Historically, the name "ethylene" was widely used and recognized in the scientific community. However, the International Union of Pure and Applied Chemistry (IUPAC), which is the governing body that sets standards for chemical nomenclature, has specific rules for naming organic compounds.

According to the IUPAC nomenclature rules, the systematic name for this molecule is "ethene." This is derived from the suffix "-ene," which is used for alkenes, and the prefix "eth-," which indicates the presence of two carbon atoms in the longest continuous chain of carbon atoms. The prefix "eth-" is derived from ethane (C2H6), the alkane with two carbon atoms.

The reference to the 1979 IUPAC nomenclature rules and the subsequent change in 1993 is an important part of the story. In 1979, IUPAC made an exception to allow the retention of the non-systematic name "ethylene" for this molecule. This was a deviation from the strict application of the IUPAC rules, which typically require the use of systematic names. However, in 1993, IUPAC reversed this decision and standardized the name to "ethene" to maintain consistency with the nomenclature system.

Despite this change, the name "ethylene" is still commonly used, particularly in the industry and in some regions, due to its historical prevalence and familiarity. However, from a strict nomenclature standpoint, the correct name according to IUPAC is "ethene."

It's also worth noting that the use of "ethene" versus "ethylene" can sometimes reflect regional preferences or the specific field of study. For example, in some parts of the world, "ethylene" might still be preferred, while in academic or research settings where adherence to IUPAC nomenclature is emphasized, "ethene" would be the term of choice.

In summary, while "ethene" and "ethylene" refer to the same chemical substance, the term "ethene" is the systematic and currently accepted IUPAC name. The use of "ethylene" persists due to historical usage and regional preferences, but when following the IUPAC nomenclature rules, one should use "ethene."

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The 1979 IUPAC nomenclature rules made an exception for retaining the non-systematic name ethylene, however, this decision was reversed in the 1993 rules so the IUPAC name is now ethene.read more >>