In chemistry, a polyoxometalate (abbreviated POM) is a polyatomic ion, usually an anion, that consists of three or more transition metal oxyanions linked together by shared oxygen atoms to form closed 3-dimensional frameworks.
 The metal atoms are usually group 6 (Mo, W) or less commonly group 5 (V, Nb, Ta) transition metals in their high oxidation states.
 They are usually colorless or orange, diamagnetic anions. Two broad families are recognized, isopolymetalates, composed of only one kind of metal and oxide, and heteropolymetalates, composed of one metal, oxide, and a main group oxyanion (phosphate, silicate, etc.).
 Many exceptions to these general statements exist.
In inorganic chemistry, a Nowotny chimney ladder phase (NCL phase) is a particular intermetallic crystal structure found with certain binary compounds. NLC phases are generally tetragonal and are composed of two separate sublattices.
 The first is a tetragonal array of transition metal atoms, generally from group 4 through group 9 of the periodic table.
 Contained within this array of transition metal atoms is a second network of main group atoms, typically from group 13 (boron group) or group 14 (carbon group).
 The transition metal atoms form a chimney with helical zigzag chain.
 The main-group elements form a ladder spiraling around the transition metal helix.
Propane ( ) is a three-carbon alkane with the molecular formula CH.
 It is a gas at standard temperature and pressure, but compressible to a transportable liquid.
 A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for barbecue grills. Propane is one of a group of liquefied petroleum gases (LP gases).
 The others include butane, propylene, butadiene, butylene, isobutylene, and mixtures thereof.
Diatomic molecules are molecules composed of only two atoms, of the same or different chemical elements.
 The prefix "di-" is of Greek origin, meaning "two".
 If a diatomic molecule consists of two atoms of the same element, such as hydrogen (H) or oxygen (O), then it is said to be homonuclear.
 Otherwise, if a diatomic molecule consists of two different atoms, such as carbon monoxide (CO) or nitric oxide (NO), the molecule is said to be heteronuclear.
A carbon–carbon bond is a covalent bond between two carbon atoms.
 The most common form is the single bond: a bond composed of two electrons, one from each of the two atoms.
 The carbon–carbon single bond is a sigma bond and is formed between one hybridized orbital from each of the carbon atoms.
 In ethane, the orbitals are sp-hybridized orbitals, but single bonds formed between carbon atoms with other hybridisations do occur (e.g. sp to sp).
 In fact, the carbon atoms in the single bond need not be of the same hybridisation.
 Carbon atoms can also form double bonds in compounds called alkenes or triple bonds in compounds called alkynes.
 A double bond is formed with an sp-hybridized orbital and a p-orbital that isn't involved in the hybridization.
 A triple bond is formed with an sp-hybridized orbital and two p-orbitals from each atom.
 The use of the p-orbitals forms a pi bond.
A primary carbon is a carbon atom which is bound to only one other carbon atom.
 It is thus at the end of a carbon chain.
 In case of an alkane, three hydrogen atoms are bound to a primary carbones (see propane in the figure on the right).
 A hydrogen atom could also be replaced by a hydroxy group, which would make the molecule to a primary alcohol.
In chemistry, a chemical compound, or simply a compound, is a molecule (or molecular entity) composed of atoms of more than one element, that are associated via chemical bonds; or a corresponding chemical species, which is a pure chemical substance composed of many identical such compound molecules.
 There are four types of compounds, depending on how the constituent atoms are held together: molecules held together by covalent bonds, ionic compounds held together by ionic bonds, intermetallic compounds held together by metallic bonds, and certain complexes held together by coordinate covalent bonds.
 Many chemical compounds have a unique numerical identifier assigned by the Chemical Abstracts Service (CAS): its CAS number.
The connectivity of a molecule often has a strong influence on its physical and chemical properties and behavior.
 Two molecules composed of the same numbers of the same types of atoms (i.e. a pair of isomers) might have completely different chemical and/or physical properties if the atoms are connected differently or in different positions.
 In such cases, a structural formula is useful, as it illustrates which atoms are bonded to which other ones.
 From the connectivity, it is often possible to deduce the approximate shape of the molecule.
Metaproscaline, or 3,4-dimethoxy-5-propoxyphenethylamine, is a lesser-known psychedelic drug.
 It is an analog of proscaline.
 Metaproscaline was first synthesized by Alexander Shulgin.
 In his book "PiHKAL (Phenethylamines i Have Known And Loved)", the dosage and the duration are unknown.
 Metaproscaline produces few to no effects.
 Very little data exists about the pharmacological properties, metabolism, and toxicity of metaproscaline.
1,1,1,2-Tetrachloropropane is a compound of chlorine, hydrogen, and carbon.
 It has chemical formula CHCl.
 The structure has a propane skeleton, but four of the hydrogen atoms are replaced by chlorine atoms.

Question: Which is composed of more atoms, Metaproscaline or Propane?
Answer: Metaproscaline