For binary (two-element) molecular compounds, Greek prefixes are employed. Ionic compounds are given numerous names. With the exception of the prefix mono-, which is not used for the first element, the prefixes are written at the beginning of the names of each element. For example, potassium iodide is called KI, while sodium chloride is called NaCl.
Binary ionic compounds can be divided into two large groups on the basis of their stability: inorganic ions and organic ions. Inorganic ions are those that contain only elements with an atomic number greater than 20. These are the most stable compounds because they cannot give up any electrons to another molecule or particle. Organic ions are those that contain elements with an atomic number between 1 and 20. These compounds can lose one or more electrons and become unstable. However, such loss of electrons does not necessarily lead to destruction of the organism containing them. For example, vitamin C is an organic ion that can lose two electrons and still remain intact. On the other hand, people who do not eat fruits or vegetables will die when their bodies produce no more vitamin C.
Ions are attracted to each other due to the electric charge on their surfaces. If an ionizer is used as a source of ions, these will be iodine ions and chlorine ions. When neutral molecules come into contact with these ions, they will be absorbed onto the surface of the ionizer basket due to the electrical attraction between them.
When naming binary ionic compounds, start with the cation (specifying the charge if necessary), then move on to the nonmetal anion (element stem +-ide). Prefixes should not be used to specify how many of each element are present; this information is inferred in the compound's name. Ionic compounds contain only positive and negative ions, so they are always balanced. For example, sodium chloride is a salt composed of equal amounts of sodium and chlorine atoms bonded to each other. Because there is no more than one atom of any single element in the compound, it is an ionic salt.
Ion pairs are formed when an ion comes together with an oppositely charged particle or molecule. Ions can be either cations or anions. Cations are positively charged particles, while anions are negatively charged particles. When two ions of opposite charge meet, they cancel out each other's charges without forming any chemical bonds. However, if several ions come together, they will form a lattice structure by attaching themselves to adjacent ions. This is called an ionic crystal or solid.
Ionic compounds can be liquid or gas at room temperature. They are usually clear or white, but colored compounds do exist. Ionic compounds are important in chemistry because they provide a way to introduce other elements into a mixture.
Prefixes are used in the naming of molecular compounds to specify the number of a specific element present in the molecule. "Mono-" means one, "di-" means two, "tri-" means three, "tetra-" means four, "penta-" means five, "hexa-" means six, "hepta-" means seven, "octo-" means eight, "nona-" means nine, and "deca" means 10. For example, monomethylamine is named after its elements: one carbon, one nitrogen, and one hydrogen.
Molecules can contain any number of different elements, but only a few element combinations are common. Ammonia is made up of one atom each of nitrogen and ammonia is composed of three molecules of nitrogen bonded together.
When a metal cation creates more than one ion, ionic compounds are named using Roman numerals. Transition metals are metals that can produce more than one ion, however not all of them can. Ionic radii for transition metals are only available for some elements so the names include both the element and its radius.
For example, iron (Fe) has a neutral atom with a radius of about 0.71 nm and two ions with radii of 1.44 and 1.50 nm. Thus, the name of the compound containing these atoms is FeIIICl2. Transitional metals are defined as those that can exist in multiple valence states or have non-integer valence. Some examples are Cu, Zn, Cd. Ionic radii for these elements are available but they are usually only given for the +1 state so the names also include this value. For CuCl2 the radius is 1.54 nm while for ZnCl2 it's 0.72 nm and 1.07 nm for CdCl2.
Lithium is used to form compounds with many elements including bromine, carbon, nitrogen, oxygen, phosphorus, sulfur and zinc. These compounds contain either Li+ or Br- anions. Ionic radii are only available for Li+, therefore the names of these compounds include both the element and its radius.
The cation of an ionic compound is named first, followed by the anion. The cation is named for its element. K+1, for example, is known as the potassium ion, just as K is known as the potassium atom. Ionic compounds containing metals other than potassium are usually named for the metal they contain.
Ions are attracted to each other because of their opposite charges. Cations have a positive charge and will attract electrons from anions which have a negative charge. This is why it is necessary to name ions before describing them in terms of numbers. For example, if you were to describe magnesium chloride as a salt, it would be called a magnesium cation (Mg2+) combined with a chlorine anion (Cl-). Magnesium is the most common metallic element found in the earth's crust. It is used in many foods as a source of dietary magnesium. Chlorine is a greenish-yellow poisonous gas that is active against bacteria and some viruses. It is stored in large quantities under water and in the intestines of animals.
Ionicity is the property of molecules or atoms that give rise to salts or acids. Ionic compounds form when non-metal elements are combined with acids or bases. These combinations can be between two different substances (a binary combination) or one single substance combined with another (a ternary combination).
Binary covalent molecules, such as carbon dioxide, are made up of only two components. Binary compound names contain prefixes that specify the amount of atoms of each nonmetal present. With one exception, this name scheme is solely used for binary nonmetal compounds. The single exception is oxygen, which has a double bond to another oxygen molecule in water. Thus, the name of oxygen-oxygen bonding contains both monoatomic and diatomic prefixes.
Greek prefixes are used to describe the number of elements present in a compound. There are three main classes of binary compounds: metal compounds, nitrogenous compounds, and phosphorusorous compounds. Within these broad categories, there are many specific compounds. This article will focus on the relationship between Greek prefixes and the elements they designate as opposed to other factors such as hybridization or multiplicity.
The presence of a Greek prefix indicates that the element it describes is incorporated into the compound in a binary form. For example, copper(II) sulfate incorporates copper and sulfur into its structure in a binary fashion. Because copper and sulfur are both nonmetals, the compound is considered to be a nonmetal binary compound. Nonmetal binary compounds make up the largest group of organic chemicals. In general, these compounds contain equal numbers of electrons in their valence shells. The only way for electrons to occupy higher energy levels is if two nonmetals attract each other with one electron from each atom.