Coordination numbers examples

Number d3 higher coordination numbers. Examples are CsCuClj (infinite single chains,... 

Crystal Type Cation Coordination Number Anion Coordination Number Examples... 

Coordination number Examples Page in text Shape... 

Conventional complexes of amines such as en, dien, and dipy are known, together with A-bonded thiocyanato complexes. With few exceptions they have high coordination numbers. Examples of such complexes are Ln en3Cl3, [La en4(CF3S03)]2+, LaL(CF3S03)2]+, and [YbL(CF3S03)]2+ (where L represents a macrocyclic octa-amine), in which coordination numbers of 9,9,10, and 9, respectively, are displayed. In aqueous solution thiocyanato complexes have appreciable formation constants, and SCN can be used as elutant for ion-exchange separations. The [Ln(NCS)6]3 ions are octahedral. 

Many chemical molecules that are not stable under normal conditions at room temperature are found in high-temperature vapors. These include gaseous molecular forms of compounds such as metal oxides or chlorides that are normally encountered as solids at room temperature. Other species found in high-temperature vapors have unusual valencies and coordination numbers. Examples are the molecules OPCl and O2PCI, which contain unusual two-coordinate trivalent and three-coordinate pentavalent phosphorus atoms, respectively. It is of interest to study such species to extend our knowledge of the structure and bonding of small molecules to new regions of the periodic table. Moreover, many such species are proposed chemical reaction intermediates. 

This is a rare coordination number. Many compounds which might appear to be three-coordinate as judged from their stoichiometry are found upon examination to have higher coordination numbers. Examples are CsCuClj (infinite single chains. —Cl—CuCU—Cl—, C.N. = 4 at 228 and 236 pm two more Cl from adjacent segments at 278 pm note the operation of the Jahn-Teller effect), KCuClj (infinite double chains, CI4—(Cu CU)—CI4, C.N. = 6, distorted octahedron), and NH4CdCl3 (infinite double chaims, C.N. = 6, undistorted). 

The d orbital splitting depends on the oxidation state of a given ion hence twb complex ions with the same shape, ligands and coordination number can differ in colour, for example... 

Oxidation state Electronic configuration Coordination number Metal atom geometry Example CAS Registry Number... 

The majority of U(V1) coordination chemistry has been explored with the trans-ddo s.o uranyl cation, UO " 2- The simplest complexes are ammonia adducts, of importance because of the ease of their synthesis and their versatihty as starting materials for other complexes. In addition to ammonia, many of the ligand types mentioned ia the iatroduction have been complexed with U(V1) and usually have coordination numbers of either 6 or 8. As a result of these coordination environments a majority of the complexes have an octahedral or hexagonal bipyramidal coordination environment. Examples iuclude U02X2L (X = hahde, OR, NO3, RCO2, L = NH3, primary, secondary, and tertiary amines, py n = 2-4), U02(N03)2L (L = en, diamiaobenzene n = 1, 2). The use of thiocyanates has lead to the isolation of typically 6 or 8 coordinate neutral and anionic species, ie, [U02(NCS)J j)/H20 (x = 2-5). 

A hydroxyl group is situated ortho to a carboxyl group which as a bidentate ligand is terminally metallized on the fiber when aftertreated with dichromate. An example is Alizarine Yellow GG [584-42-9] (50) (Cl Mordant Yellow 1 Cl 14025). Cr(III) has a coordination number of six, and therefore normally two dye molecules of the sahcyhc type are chelated to the metal ion. 

Ceitain acid dyes can have thek fastness piopeities impioved by combining the dye with a metal atom (chelation). The most common metal is chromium, although cobalt is sometimes used, and this can be introduced in a number of ways. The basic mechanism is donation of electron pans by groups in the dye (ligands) to a metal ion. For example, has a coordination number of 6, and therefore will accept six lone pans of electrons. Typical ligand groups... 

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