It is a collection of rules for naming inorganic compounds, as recommended by the International Union of Pure and Applied Chemistry (IUPAC).
These are: Additionally there are recommendations for the following: For a simple compound such as AlCl3 the different naming conventions yield the following: Throughout the recommendations the use of the electronegativity of elements for sequencing has been replaced by a formal list which is loosely based on electronegativity.
The recommendations still use the terms electropositive and electronegative to refer to an element's relative position in this list.
A simple rule of thumb ignoring lanthanides and actinides is: The full list, from highest to lowest "electronegativity" (with the addition of elements 112 through 118, that had not yet been named in 2005, to their respective groups): Note "treat separately" means to use the decision table on each component An indeterminate sample simply takes the element name.
Similarly other examples of lattice compounds are: As an alternative to di-, tri- prefixes either charge or oxidation state can be used.
This naming method generally follows established IUPAC organic nomenclature.
Acceptable alternative names for some of the parent hydrides are water rather than oxidane and ammonia rather than azane.
Where a compound has non standard bonding as compared to the parent hydride for example PCl5 the lambda convention is used.
Examples are: The recommendations describe three ways of assigning "parent" names to homonuclear monocyclic hydrides (i.e single rings consisting of one element): The stoichiometric name is followed by the number of hydrogen atoms in brackets.
Examples are: For organometallic compounds of groups 1–2 can use additive (indicating a molecular aggregate) or compositional naming.
Examples are: However the recommendation notes that future nomenclature projects will be addressing these compounds.
The number of ligands coordinating is indicated by the prefixes di-, tri-, tetra- penta- etc.
For example in basic beryllium acetate which can be visualised as a tetrahedral arrangement of Be atoms linked by 6 acetate ions forming a cage with a central oxide anion, the formula and name are as follows: The μ4 describes the bridging of the central oxide ion.
(Note the use of the kappa convention to describe the bridging of the acetate ion where both oxygen atoms are involved.)
For example: Where there is more than one bond formed from a ligand by a particular element a numerical superscript gives the count.
A configuration index is determined from the positions of the ligands and together with the polyhedral symbol is placed at the beginning of the name.
For example in the complex (SP-4-3)-(acetonitrile)dichlorido(pyridine)platinum(II) the (SP-4-3) at the beginning of the name describes a square planar geometry, 4 coordinate with a configuration index of 3 indicating the position of the ligands around the central atom.
Additive nomenclature is generally recommended for organometallic compounds of groups 3-12 (transition metals and zinc, cadmium and mercury).
The terminology does NOT apply to compounds of the s- or p-block elements such as Ba(C5H5)2 or Sn(C5H5)2.
A pair of brackets contain a count of the bonds formed (if greater than 1), followed by the italicised element atomic symbols separated by an "em-dash".
[4] Examples: decacarbonyldimanganese bis(pentacarbonylmanganese)(Mn—Mn) dodecacarbonyltetrarhodium tri-μ-carbonyl-1:2κ2C;1:3κ2C;2:3κ2C-nonacarbonyl- 1κ2C,2κ2C,3κ2C,4κ3C-[Td-(13)-Δ4-closo]-tetrarhodium(6 Rh—Rh) or tri-μ-carbonyl-1:2κ2C;1:3κ2C;2:3κ2C-nonacarbonyl- 1κ2C,2κ2C,3κ2C,4κ3C-tetrahedro-tetrarhodium(6 Rh—Rh) The recommendations include a description of hydrogen names for acids.
The recommendations give a full list of acceptable names for common acids and related anions.
However a mineral name can be used to specify the structure type in a formula e.g. A simple notation may be used where little information on the mechanism for variability is either available or is not required to be conveyed: Where there is a continuous range of composition this can be written e.g., K(Br,Cl) for a mixture of KBr and KCl and (Li2,Mg)Cl2 for a mixture of LiCl and MgCl2.
Note that cation vacancies in CoO could be described by CoO1−x Point defects, site symmetry and site occupancy can all be described using Kröger–Vink notation, note that the IUPAC preference is for vacancies to be specified by V rather than V (the element vanadium).