Terpenes are biomolecules with a linear, cyclic or mixed linear and cyclic structure formed by isoprene units. Terpenes are produced by different plants, in particular by conifers of which they are the fundamental components of resins and essential oils (read the sheet Christmas is pine scent). They also are components of flowers aroma, characterizing the scent of each plant, such as rosemary and other aromas used in cooking. Biochemically, they are the biosynthetic precursors of steroids and carotenoids.
Among the terpenes we include:
• the pinene, which is found in coniferous resin;
• limonene, which is found in citrus peel;
• camphene (2,2-dimethyl-3-methylene-bicycle[2.2.1]heptane) which is a constituent of turpentine, citronella oil and other essential oils;
• myrcene (7-Methyl-3-methylideneocta-1,6-diene) which is the aroma of essential oils widely used in the perfume industry;
If you have not already done so, download Avogadro for free and watch the tutorials if necessary.
Open an Avogadro page for each compound and recall the molecules using the current names or IUPAC names (file → import → fetch file by chemical name). After observing the structure and properties (view → properties) indicate which characteristics have in common and what they differ. Then detect if they have linear, cyclical or mixed structure.