Chemputer: classification of central atom in a compound

Use this form to build your compund. You must define the atom of interest, the overall charge, and at least one attached group. The Chemputer will then calculate for the central atom:

Valence number (VN)
Coordination number (CN)
Oxidation number (ON)
MLXZ classification
MLXZ equivalent neutral class (ENC) classification

* denotes required field

Numbers of groups		Attached groups or ligands
Central element	*
Overall charge on compound	*
1st group	*	1st group	*
2nd group (if any)		2nd group
3rd group (if any)		3rd group
4th group (if any)		4th group

Classification of central element calculator

Use this form to build your compund. There are a number of points:

The valence number (VN) is the number of electrons that the central atom uses in bonding
The formal coordination number (CN) in most cases is the number of attached atoms but normal practice requires π-bound systems such as an alkene to contribute 1, not 2, to the count. Similarly, cyclopentadienyl and arenes contribute 3 not 5 or 6.
The oxidation number (VN) is often referred to as the oxidation state but IUPAC prefer the term oxidation number as this number is not a state of the compound.
The MLXZ class and the equivalent neutral class in some cases may require modification if the compound is particularly symmetric or has polyfunctional ligands.
The electron number (EN) is the number of electrons associated with the central atom and is made up from the atom's own electrons added to those contributed by the attached groups (usually called ligands in metal complexes).

References

The classification calculations used here are described in detail within the Oxford Primer:

Mark J. Winter, "d-Block Chemistry", Oxford University Press, 2nd edition, 2015, ISBN: 978-0-19-870096-8.

For an introduction to MLXZ classifications see:

M.L.H. Green, "A new approach to the formal classification of covalent compounds of the elements", J. Organometal. Chem., 1995, 500 127–148, doi: 10.1016/0022-328X(95)00508-N.

Chemputer, a set of simple calculators for chemistry: https://winter.group.shef.ac.uk/chemputer/
Copyright 1993-2023 Prof Mark J. Winter [Department of Chemistry, The University of Sheffield]. All rights reserved.