This 19-electron species is a good reducing agent, being readily oxidised to the yellow 18-electron cobaltacenium cation, which is isoelectronic with ferrocene. Reaction of anhydrous CoCl 2 with sodium cyclopentadienylide in THF gives the black sandwich compound cobaltocene. For example, the reaction of 1-norbonyllithium with CoCl 2 produces the brown, thermally stable cobalt(IV) tetralkyl - the only compound of its kind for which the detailed structure is fully known : In the laboratory, cobalt(II) chloride serves as a standard precursor for the synthesis of other cobalt compounds. Otherwise, aqueous solutions of cobalt(II) chlorides behave like other cobalt(II) salts, such as precipitating CoS upon treatment with H 2S. These cobalt (II) complexes are usually either octahedral or tetrahedral. Similarly, paper impregnated with cobalt chloride, known as "cobalt chloride paper" is used to detect the presence of water.ĬoCl 2♶H 2O and CoCl 2 are weak Lewis acids that convert to many other complexes. When cobalt(II) chloride is added as an indicator, the drying agent is blue when still active, pink when exhausted, corresponding to anhydrous and hydrated CoCl 2, respectively. In the US calcium sulfate is sold as a drying agent under the trade name Drierite. ![]() The hydrated form can be prepared from cobalt(II) hydroxide or cobalt(II) carbonate and hydrochloric acid.Ī common use for cobalt(II) chloride was for the detection of moisture, for example in drying agents such as silica gel this use was disscontinued due to the carcenogenic nature of cobalt salts. CoCl 2♶H 2O is deliquescent and the anhydrous salt CoCl 2 is hygroscopic, readily converting to the hydrate.Ĭobalt(II) chloride can be prepared in its anhydrous form from cobalt metal and chlorine gas: It has the interesting property that a concentrated aqueous solution is red at room temperature, but becomes blue when heated. This species dissolves readily in water and alcohol. In the solid state CoCl 2♶H 2O contains trans-♲H 2O, two water molecules in its formula unit being water of crystallization. The rose hexahydrate is one the most common cobalt compounds in the laboratory.Īqueous solutions of both CoCl 2 and the hydrate contain the species 2+. Because of this dramatic color change and the ease of the hydration/dehydration reaction, "cobalt chloride" is used as an indicator for water. CoCl 2 is blue, and CoCl 2♶H 2O is deep rose. Rhodium(III) chloride Iridium(III) chlorideĮxcept where noted otherwise, data are given for materials in their standard state (at 25 ☌, 100 kPa) Infobox disclaimer and referencesĬobalt(II) chloride is the chemical compound with the formula CoCl 2, although the term is used also to refer to the hexahydrate, which is a different chemical compound. 2 Dangerous for the environment ( N)Ĭobalt(II) fluoride Cobalt(II) bromide Cobalt(II) iodide Cobalt(II) oxide Other heavy metals should be collected separately.Toxic ( T) Carc. to AbfallverzeichnisV - Waste Catalogue Ordinance, Appendix 3). In this context, heavy metal means any compound of antimony, arsenic, cadmium, chromium(VI), copper, lead, nickel and tin, as well as these subtances in metallic form, if they are classified as hazardous (acc. Neither Raney nickel itself nor any filter residues should be allowed to dry out, otherwise they will spontaneously ignite in air. Stir Raney nickel (also: Urushibara nickel) in the form of an aqueous suspension into hydrochloric acid (Cat. P308 + P313: IF exposed or concerned: Get medical advice/ attention.Ħ.1D Non-combustible, acute toxic Cat.3 / toxic hazardous materials or hazardous materials causing chronic effectsġ5 Heavy metal-containing solutions and solids: container E. Remove contact lenses, if present and easy to do. ![]() P305 + P351 + P338: IF IN EYES: Rinse cautiously with water for several minutes. P302 + P352: IF ON SKIN: Wash with plenty of water. P301 + P312: IF SWALLOWED: Call a POISON CENTER/doctor if you feel unwell. P280: Wear protective gloves/ protective clothing/ eye protection/ face protection/ hearing protection. H410: Very toxic to aquatic life with long lasting effects. H341: Suspected of causing genetic defects. H334: May cause allergy or asthma symptoms or breathing difficulties if inhaled. ![]() H317: May cause an allergic skin reaction.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |