Answer: A monodentate ligand has only one donor atom used to bond to the central metal atom or ion. The one example are halide ions such as C r , F − , I − and cyano, etc. • Ambident Ligand: An ambident ligand is that ligand which binds with the central metal atom or ion through more than one site. For example, when chemists draw the structure for [Ni(NH 3) 6] 2+, each ammonia ligand is represented as a sphere.The sphere represents the donor atom of the ligand. Monodentate ligands are Lewis bases that donate a single pair ("mono") of electrons to a metal atom. Monodentate ligands are sometimes referred to as being "one toothed" because they bind to the central metal atom at one point. For example, ammonia and chloride ion are monodentate ligands of copper in the complexes [Cu(NH 3) 6] 2+ and [CuCl 6] 2+. Typical monodentate ligands are given in the figure below. Monodentate ligands have one atom that can bind to a central atom or ion. Ligands: The molecular or ionic species which gets attached directly to the central metal atom or ion during the formation of a complex is called a ligand . Bidentate ligands bind through two donor sites. Chemists often represent ligands as spheres for simplicity, even though the "sphere" sometimes has three-dimensional structure of its own. Non-chelating ligands such as ammonia (NH 3) are monodentate, with one point of attachment (one tooth). The halides, phosphines, ammonia and amines seen previously are monodentate ligands. Usually monodentate ligands fall under this category of ligands. My favourite is probably $\ce{[Cr2(OAc)4(H2O)2]}$ or chromium(II) acetate monohydrate. Bidentate ligands have two donor sites. The lone pair on N is pointing in the opposite direction and cannot bind to the metal. Bidentate means "two-toothed." Other ligands are described as bidentate because they have two points of attachment. There are, however, exceptions. For example, in the complex [Co(NH 3) 6] 3+, Co 3+ is the central atom and in the co-ordination compound [Pt(NH 3) 4][PtCl 4], Pt 2+ is the central ion. Monodentate ligands bind through only one donor atom. Ethylenediamine is also an example of a chelating ligand. The same goes if C attaches to the metal. Monodentate ligand is a ligand that has only one atom that coordinates directly to the central atom in a complex. Coordinate bonds are usually not very strong, do not liberate enough energy and it would thus be more favourable for one of the two $\ce{O-M}$ bonds to be broken leading to acetate as a monodentate ligand. Ethylenediamine (en) is a typical bidentate ligand. Answer: Try to visualize this...because cyanide is a linear molecule, if the N attaches to metal, then the lone pair on C is pointing 180 degrees away and there is no way for this lone pair to wrap around and bind to the metal. Monodentate ligands can be either ions or neutral molecules. Monodentate means "one-toothed." A polydentate ligand has more than one donor site. Other ligands can attach to the metal more than once. This review mainly covers the ligand shape (length and angle) dependent variation of M n L 2n (M = square-planar coordinated metal center; L = bis-monodentate ligand; n = nuclearity) cage structures. Water (H 2 O) and ammonia (NH 3) are examples of neutral monodentate ligands. The term "monodentate" can be translated as "one tooth," referring to the ligand binding to the center through only one atom. Tridentate ligands have three binding sites. Most cage structures discussed here are of low nuclearity (i.e. Each end of this molecule contains a pair of nonbonding electrons that can form a covalent bond to a metal ion. The most common example of these types of ligands is EDTA (ethylene di–amine tetra acetic acid). An example of a bidentate ligand is ethylenediamine. Ligand Examples . 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