The halides, phosphines, ammonia and amines seen previously are monodentate ligands. Ligand Examples . • Ambident Ligand: An ambident ligand is that ligand which binds with the central metal atom or ion through more than one site. Bidentate means "two-toothed." Monodentate ligands have one atom that can bind to a central atom or ion. Monodentate ligands can be either ions or neutral molecules. 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. Monodentate ligands bind through only one donor atom. There are, however, exceptions. Monodentate means "one-toothed." Bidentate ligands bind through two donor sites. Ethylenediamine (en) is a typical bidentate ligand. The one example are halide ions such as C r , F − , I − and cyano, etc. 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 . 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. 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. 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. My favourite is probably $\ce{[Cr2(OAc)4(H2O)2]}$ or chromium(II) acetate monohydrate. For example, ammonia and chloride ion are monodentate ligands of copper in the complexes [Cu(NH 3) 6] 2+ and [CuCl 6] 2+. Usually monodentate ligands fall under this category of ligands. Chemists often represent ligands as spheres for simplicity, even though the "sphere" sometimes has three-dimensional structure of its own. 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. Monodentate ligands are sometimes referred to as being "one toothed" because they bind to the central metal atom at one point. Each end of this molecule contains a pair of nonbonding electrons that can form a covalent bond to a metal ion. Answer: A monodentate ligand has only one donor atom used to bond to the central metal atom or ion. Tridentate ligands have three binding sites. Water (H 2 O) and ammonia (NH 3) are examples of neutral monodentate ligands. A polydentate ligand has more than one donor site. The same goes if C attaches to the metal. Bidentate ligands have two donor sites. The lone pair on N is pointing in the opposite direction and cannot bind to the metal. Most cage structures discussed here are of low nuclearity (i.e. An example of a bidentate ligand is ethylenediamine. Monodentate ligands are Lewis bases that donate a single pair ("mono") of electrons to a metal atom. The term "monodentate" can be translated as "one tooth," referring to the ligand binding to the center through only one atom. Typical monodentate ligands are given in the figure below. Monodentate ligand is a ligand that has only one atom that coordinates directly to the central atom in a complex. Ethylenediamine is also an example of a chelating ligand. Non-chelating ligands such as ammonia (NH 3) are monodentate, with one point of attachment (one tooth). Other ligands are described as bidentate because they have two points of attachment. Other ligands can attach to the metal more than once. 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