Polycyclic nonaromatic hydrocarbons

Basketane is a polycyclic alkane with the chemical formula C10H12. The name is taken from its structural similarity to a basket shape. Basketane was first synthesized in 1966, independently by Masamune and Dauben and Whalen.

Tetrahedrane is a hypothetical platonic hydrocarbon with chemical formula and a tetrahedral structure. The molecule would be subject to considerable angle strain and has not been synthesized . However, a number of derivatives have been prepared. In a more general sense, the term tetrahedranes is used to describe a class of molecules and ions with related structure, e.g. white phosphorus.

Dodecahedrane is a chemical compound, a hydrocarbon with formula , whose carbon atoms are arranged as the vertices (corners) of a regular dodecahedron. Each carbon is bound to three neighbouring carbon atoms and to a hydrogen atom. This compound is one of the three possible Platonic hydrocarbons, the other two being cubane and tetrahedrane.

Twistane (IUPAC name: tricyclo[4.4.0.03,8]decane) is an organic compound with the formula C10H16. It is a cycloalkane and an isomer of the simplest diamondoid, adamantane, and like adamantane, is not very volatile. Twistane was named for the way its rings are permanently forced into the cyclohexane conformation known as the "twist-boat". The compound was first reported by Whitlock in 1962.

Longifolene is a common sesquiterpene. It is an oily liquid hydrocarbon found primarily in the high-boiling fraction of certain pine resins. The name is derived from that of a pine species from which the compound was isolated. It is a tricyclic chiral molecule. The enantiomer commonly found in pines and other higher plants exhibits a positive optical rotation of +42.73°. The other enantiomer (optical rotation −42.73°) is found in small amounts in certain fungi and liverworts. ==Occurrence== Terpentine obtained from Pinus longifolia (obsolete name for Pinus roxburghii Sarg.) contains as much as

Oleanane is a natural triterpenoid. It is commonly found in woody angiosperms and as a result is often used as an indicator of these plants in the fossil record. It is a member of the oleanoid series, which consists of pentacyclic triterpenoids (such as beta-amyrin and taraxerol) where all rings are six-membered.

Pagodane is an organic compound with formula whose carbon skeleton was said to resemble a pagoda, hence the name. It is a polycyclic hydrocarbon whose molecule has the D2h point symmetry group. The compound is a highly crystalline solid that melts at 243 °C, is barely soluble in most organic solvents and moderately soluble in benzene and chloroform. It sublimes at low pressure.

thumb|Iceane, colored by symmetry, Carbon in black and blue, hydrogen in white and cyan Iceane is a saturated polycyclic hydrocarbon with formula . It has a cage-like molecular structure, whose carbon skeleton can be viewed as three fused cyclohexane rings in the boat conformation; or as two such rings in the chair conformation, connected by three parallel axial bonds. The spatial arrangement of carbon atoms in iceane is the lonsdalite crystalline structure.

Heptalene is a polycyclic hydrocarbon with chemical formula , composed of two fused cycloheptatriene rings. It is an unstable, non-planar compound which is non-aromatic. The dianion, however, satisfies Hückel's rule, is thermally stable, and is planar.

[[File:Propellanes.png|thumb|300px|right|Some propellanes. From left to right: [1.1.1]propellane, [2.2.2]propellane, and 1,3-dehydroadamantane (a methylene-bridged derivative of [3.3.1]propellane).]]

Basketene (IUPAC name: pentacyclo[4.4.0.02,5.03,8.04,7]dec-9-ene

Spiropentadiene, or bowtiediene, is a hydrocarbon with formula . The simplest spiro-connected diene, it is very unstable—decomposing even below −100 °C—due to its high bond strain and does not occur in nature. Its synthesis was reported in 1991.

Gonane (cyclopentanoperhydrophenanthrene) is a chemical compound with formula , whose structure consists of four hydrocarbon rings fused together: three cyclohexane units and one cyclopentane. It can also be viewed as the result of fusing a cyclopentane molecule with a fully hydrogenated molecule of phenanthrene, hence the more descriptive name "perhydrocyclopenta[a]phenanthrene". The non-systematic version of the above name is "cyclopentanoperhydrophenanthrene".

Perhydropyrene is a hydrocarbon similar to pyrene. Single bonds with hydrogen replace the double bonds in the benzene rings.

[[File:Fenestranes.png|thumb|400px|right|Fenestranes, from left to right: generic fenestrane, [4.4.4.4]fenestrane with carbon atoms shown and [5.5.5.5]fenestrane]] A fenestrane in organic chemistry is a type of chemical compound with a central quaternary carbon atom which serves as a common vertex for four fused carbocycles. They can be regarded as spiro compounds twice over. Because of their inherent strain and instability, fenestranes are of theoretical interest to chemists. The name—proposed in 1972 by Vlasios Georgian and Martin Saltzman—is derived from the Latin word for window, fenestra.

Isoindene is a flammable polycyclic hydrocarbon with chemical formula C9H8. It is composed of a cyclohexadiene ring fused with a cyclopentadiene ring.

Cuneane () is a saturated hydrocarbon with the formula and a 3D structure resembling a wedge, hence the name. Cuneane may be produced from cubane by metal-ion-catalyzed σ-bond rearrangement. Similar reactions are known for () and bishomocubane ().

thumb|Simple ladderane structure thumb|A licorice model of the chemical structure of the 3-ladderane molecule

Spiropentane is a hydrocarbon with formula . It is the simplest spiro-connected cycloalkane, a triangulane. It took several years after the discovery in 1887 until the structure of the molecule was determined. According to the nomenclature rules for spiro compounds, the systematic name is spiro[2.2]pentane. However, there can be no constitutive isomeric spiropentanes, hence the name is unique without brackets and numbers.

thumb|Diamantane, colored by symmetry, carbon black, blue, purple, and hydrogen as white, yellow, and cyan Diamantane (also called congressane) is an organic compound that is a member of the diamondoids. These are cage hydrocarbons with structures similar to a subunit of the diamond lattice. It is a colorless solid that has been a topic of research since its discovery in oil and separation from deep natural gas condensates. Diamondoids such as diamantane exhibit unusual properties, including low surface energies, high densities, high hydrophobicities, and resistance to oxidation.

The prismanes are a class of hydrocarbon compounds consisting of prism-like polyhedra of various numbers of sides on the polygonal base. Chemically, it is a series of fused cyclobutane rings (a ladderane, with all-cis/all-syn geometry) that wraps around to join its ends and form a band, with cycloalkane edges. Their chemical formula is (C2H2)n, where n is the number of cyclobutane sides (the size of the cycloalkane base), and that number also forms the basis for a system of nomenclature within this class. The first few chemicals in this class are:

Tricyclodecane (TCD) is an organic compound with the formula C10H16. It is classed as a hydrocarbon. It has two main stereoisomers–the endo and exo forms. Its primary use in the exo form is as a component of jet fuel. It is used here primarily because of its high energy density. The exo isomer also has a low freezing point. Because of this, its properties have been studied extensively. It is often called tetrahydrodicyclopentadiene.

Calicene or triapentafulvalene is a hydrocarbon of the fulvalene class with chemical formula C8H6, composed of a cyclopentadiene ring and a cyclopropene ring linked by a double bond. Its name is derived from the Latin calix meaning "goblet", from its shape.