Transition metal perchlorate complexes are coordination complexes with one or more perchlorate ligands. Perchlorate can bind to metals through one, two, three, or all four oxygen atoms. Usually however, perchlorate is a counterion, not a ligand.
Transition metal perchlorate complexes are coordination complexes with one or more perchlorate ligands. Perchlorate can bind to metals through one, two, three, or all four oxygen atoms. Usually however, perchlorate is a counterion, not a ligand.
Homoleptic complexes, i.e. complexes where all the ligands are the same (in this case perchlorate), are of fundamental interest because of their simple stoichiometries.
Several anhydrous metal diperchlorate complexes are known but most are not molecular (and hence, not complexes). For example, many compounds with the formula M(ClO4)2 are coordination polymers (M = Mn, Fe, Co, Ni, Cu). An exception to this pattern is palladium(II) perchlorate Pd(ClO4)2, which is a square planar complex consisting of a pair of bidentate perchlorate ligands. Furthermore, anhydrous Cu(ClO4)2 is sublimable, which implies the existence of molecular Cu(ClO4)2. [1]
Titanium(IV) perchlorate and zirconium(IV) perchlorate are molecular, featuring four bidentate perchlorate ligands. They are volatile.
More common than homoleptic complexes are those with two or more types of ligands. A classic case is the dicationic complex pentamminecobalt(III) perchlorate, which had resisted formation by conventional substitution reactions. [2] It was prepared by oxidation of the azide complex: [3]
Another mixed ligand complex is the perchlorate complex of the ferric derivative of octaethylporphyrin. [4]
![View of the structure of hydrated copper perchlorate, showing the well separated
[Cu(H2O)6] and
ClO-4 ions. Color code: red = O, Cu, green = Cl. Copper(II)-perchlorate-hexahydrate-unit-cell-3D-bs-17.png](http://upload.wikimedia.org/wikipedia/commons/thumb/3/3f/Copper%28II%29-perchlorate-hexahydrate-unit-cell-3D-bs-17.png/220px-Copper%28II%29-perchlorate-hexahydrate-unit-cell-3D-bs-17.png)
Being the conjugate base of the strongly acidic perchloric acid, perchlorate is very weakly basic. It is more commonly encountered as a counterion in coordination chemistry. Illustrative of its low basicity is the ability of water to outcompete perchlorate as a ligand for metal ions is indicated by the multitude of aquo complexes with noncoordinated perchlorate. Ferrous perchlorate, cobalt(II) perchlorate, chromium(III) perchlorate, manganese(II) perchlorate, nickel(II) perchlorate, and copper(II) perchlorate are commonly encountered as their hexaaquo complexes. [5]
The preparation of perchlorate complexes can be challenging because perchlorate is a weakly ligand.
Chlorine trioxide is an important precursor to anhydrous perchlorate complexes. It serves as a source of ClO+2 and ClO−4. It reacts with vanadium pentoxide (V2O5) to give VO2(ClO4) and VO(ClO4)3. Hydrated mercury and cadmium perchlorates can be dehydrated with Cl2O6, affording anhydrous compounds. [6]
In some cases, chlorine trioxide serves both as an oxidant and a dehydrating agent:
Silver perchlorate, which has some solubility in noncoordinating solvents, reacts with some metal chlorides to give the corresponding perchlorate complex. [4]
Anhydrous perchlorate complexes are susceptible to hydrolysis:
Upon heating, perchlorate complexes yield oxides, evolving chlorine oxides in the process. For example, thermolysis of titanium perchlorate gives TiO2, ClO2, and O2 The titanyl species TiO(ClO4)2 is an intermediate in this decomposition. [7]
Perchlorate complexes and the reagents used to prepare them are often dangerously explosive intrinsically and especially in contact with organic compounds. [6]
Inorganic chemistry deals with synthesis and behavior of inorganic and organometallic compounds. This field covers chemical compounds that are not carbon-based, which are the subjects of organic chemistry. The distinction between the two disciplines is far from absolute, as there is much overlap in the subdiscipline of organometallic chemistry. It has applications in every aspect of the chemical industry, including catalysis, materials science, pigments, surfactants, coatings, medications, fuels, and agriculture.
Perchloric acid is a mineral acid with the formula HClO4. Usually found as an aqueous solution, this colorless compound is a stronger acid than sulfuric acid, nitric acid and hydrochloric acid. It is a powerful oxidizer when hot, but aqueous solutions up to approximately 70% by weight at room temperature are generally safe, only showing strong acid features and no oxidizing properties. Perchloric acid is useful for preparing perchlorate salts, especially ammonium perchlorate, an important rocket fuel component. Perchloric acid is dangerously corrosive and readily forms potentially explosive mixtures.
Iron(III) chloride describes the inorganic compounds with the formula FeCl3(H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated forms which are both hygroscopic. They feature iron in its +3 oxidation state. The anhydrous derivative is a Lewis acid, while all forms are mild oxidizing agents. It is used as a water cleaner and as an etchant for metals.
Titanium tetrachloride is the inorganic compound with the formula TiCl4. It is an important intermediate in the production of titanium metal and the pigment titanium dioxide. TiCl4 is a volatile liquid. Upon contact with humid air, it forms thick clouds of titanium dioxide and hydrochloric acid, a reaction that was formerly exploited for use in smoke machines. It is sometimes referred to as "tickle" or "tickle 4", as a phonetic representation of the symbols of its molecular formula.
Copper(II) chloride, also known as cupric chloride, is an inorganic compound with the chemical formula CuCl2. The monoclinic yellowish-brown anhydrous form slowly absorbs moisture to form the orthorhombic blue-green dihydrate CuCl2·2H2O, with two water molecules of hydration. It is industrially produced for use as a co-catalyst in the Wacker process.
Rhodium(III) chloride refers to inorganic compounds with the formula RhCl3(H2O)n, where n varies from 0 to 3. These are diamagnetic red-brown solids. The soluble trihydrated (n = 3) salt is the usual compound of commerce. It is widely used to prepare compounds used in homogeneous catalysis.
Sodium perchlorate is an inorganic compound with the chemical formula NaClO4. It consists of sodium cations Na+ and perchlorate anions ClO−4. It is a white crystalline, hygroscopic solid that is highly soluble in water and ethanol. It is usually encountered as sodium perchlorate monohydrate NaClO4·H2O. The compound is noteworthy as the most water-soluble of the common perchlorate salts.
Dichlorine hexoxide is the chemical compound with the molecular formula Cl
2O
6, which is correct for its gaseous state. However, in liquid or solid form, this chlorine oxide ionizes into the dark red ionic compound chloryl perchlorate [ClO
2]+
[ClO
4]−
, which may be thought of as the mixed anhydride of chloric and perchloric acids. This compound is a notable perchlorating agent.
Chlorine perchlorate is a chemical compound with the formula Cl2O4. This chlorine oxide is an asymmetric oxide, with one chlorine atom in +1 oxidation state and the other +7, with proper formula ClOClO3. It is produced by the photodimerization of chlorine dioxide (ClO2) at room temperature by 436 nm ultraviolet light:
Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. A few metal halides are discrete molecules, such as uranium hexafluoride, but most adopt polymeric structures, such as palladium chloride.
Perchloratoborate is an anion of the form [B(ClO4)4]−. It can form partly stable solid salts with heavy alkali metals. They are more stable than nitratoborate salts. K[B(ClO4)4] decomposes at 35 °C, Rb[B(ClO4)4] is stable to 50 °C, and Cs[B(ClO4)4] can exist up to 80 °C.
Copper(II) perchlorate is an inorganic compound with the chemical formula Cu(ClO4)2(H2O)x. The anhydrous solid is rarely encountered but several hydrates are known. Most important is the perchlorate salt of the aquo complex copper(II) perchlorate hexahydrate, [Cu(H2O)6]2+.
Titanium nitrate is the inorganic compound with formula Ti(NO3)4. It is a colorless, diamagnetic solid that sublimes readily. It is an unusual example of a volatile binary transition metal nitrate. Ill defined species called titanium nitrate are produced upon dissolution of titanium or its oxides in nitric acid.
Titanium perchlorate is a molecular compound of titanium and perchlorate groups with formula Ti(ClO4)4. Anhydrous titanium perchlorate decomposes explosively at 130 °C and melts at 85 °C with a slight decomposition. It sublimes in a vacuum as low as 70 °C. Being a molecular with four perchlorate ligands, it is an unusual example of a transition metal perchlorate complex.
Zirconium perchlorate is an inorganic compound with the formula Zr(ClO4)4. It is a hygroscopic colorless solid that sublimes in a vacuum at 70 °C. These properties show that the compound is covalently bonded molecule, rather than a salt. It is an example of a transition metal perchlorate complex.
Iron(II) perchlorate is the inorganic compound with the formula Fe(ClO4)2·6H2O. A green, water-soluble solid, it is produced by the reaction of iron metal with dilute perchloric acid followed by evaporation of the solution:
Nickel(II) perchlorate is a collection of inorganic compounds with the chemical formula of Ni(ClO4)2(H2O)x. Its colors of these solids vary with the degree of hydration. For example, the hydrate forms cyan crystals, the pentahydrate forms green crystals, but the hexahydrate (Ni(ClO4)2·6H2O) forms blue crystals. Nickel(II) perchlorate hexahydrate is highly soluble in water and soluble in some polar organic solvents.
Samarium(III) perchlorate is an inorganic compound with the chemical formula Sm(ClO4)3.
Nitrosyl perchlorate is the inorganic compound with the formula NO(ClO4). A hygroscopic white solid, it is the salt of the nitrosonium cation with the perchlorate anion. It is an oxidant and strong electrophile, but has fallen out of use with the availability of the closely related salt nitrosonium tetrafluoroborate NO(BF4).
Cobalt(II) perchlorate is an inorganic chemical compound with the formula Co(ClO4)2·nH2O (n = 0,6). The pink anhydrous and red hexahydrate forms are both hygroscopic solids.