Tetracoordinate
Encyclopedia
Tetracoordinate in coordination chemistry generally refers to four ligand
s or atomic attachments to a single metal centre. Tetracoordinate species can form tetrahedral
, square planar or pyramidal
geometries. This is usually dictated by lone electron pairs
on the metal centre.
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...
s or atomic attachments to a single metal centre. Tetracoordinate species can form tetrahedral
Tetrahedral molecular geometry
In a tetrahedral molecular geometry a central atom is located at the center with four substituents that are located at the corners of a tetrahedron. The bond angles are cos−1 ≈ 109.5° when all four substituents are the same, as in CH4. This molecular geometry is common throughout the first...
, square planar or pyramidal
Trigonal pyramid (chemistry)
In chemistry, a trigonal pyramid is a molecular geometry with one atom at the apex and three atoms at the corners of a trigonal base. When all three atoms at the corners are identical, the molecule belongs to point group C3v. One example of a molecule with a trigonal pyramidal geometry is ammonia...
geometries. This is usually dictated by lone electron pairs
Lone pair
In chemistry, a lone pair is a valence electron pair without bonding or sharing with other atoms. They are found in the outermost electron shell of an atom, so lone pairs are a subset of a molecule's valence electrons...
on the metal centre.