Chloroanion Explained

A chloroanion is an anion that contains an element and chlorine atoms. They are also known as complex chlorides. They can occur in salts, or in solution, but not as pure acids. They mostly can be considered as chlorometallates^[1] which are a subclass of halometallates.

The maximum number of chlorido- ligands around a central atom may not be as many as for fluoroanions, as the chlorine atom is bigger than the fluorine.^[2] Some chloroanions are dimeric, where there is a bond between a pair of metal atoms, or some of the chloro ligands are in a bridge position, connected to two atoms.^[3]

Some chloroanions are stable in a solution in water, whereas others are decomposed. They may be stable in a molten salt, such as an ionic liquid.^[4] In the solid form some are only stable with large cations, as when there are small cations they may form two separate chloride salt phases.

Chloroanions include many transition metal chloride complexes, but there are also chloroanions for main-group elements, including some non-metals.

List

• Tetrachloroberyllate ^[5]
• Tetrachloromagnesate ^[6]
• Tetrachloroborate ^[7]
• Tetrachloroaluminate ^[8]
• Hexachloroaluminate ^[9]
  • • • • • • Tetrachlorogallate(III) Hexachlorothallate(III) Hexachlorogermanate(IV) Hexachlorophosphate(V) Hexachloroarsenate(V) Hexachlorochromate(III) Nonachlorodichromate(III), contains two chromium atoms are linked via three chloride bridges
• Octachlorodimolybdate(II), contains quadruple bond

Notes and References

1. Web site: chlorometallate anion - Ontology Browser - Rat Genome Database . rgd.mcw.edu.
2. Book: Wulfsberg . Gary . Inorganic Chemistry . 16 March 2000 . University Science Books . 978-1-891389-01-6 . 114 . en.
3. Book: Wulfsberg . Gary . Inorganic Chemistry . 16 March 2000 . University Science Books . 978-1-891389-01-6 . en. 750.
4. Estager . Julien . Oliferenko . Alexander A. . Seddon . Kenneth R. . Swadźba-Kwaśny . Małgorzata . Chlorometallate(iii) ionic liquids as Lewis acidic catalysts – a quantitative study of acceptor properties . Dalton Transactions . 2010 . 39 . 47 . 11375–11382 . 10.1039/C0DT00895H. 20981382 .
5. Book: Raghavan . P. S. . Concepts And Problems In Inorganic Chemistry . 1998 . Discovery Publishing House . 978-81-7141-418-5 . 95 . en.
6. Sobota . Piotr . Reaction of Grignard reagent with tetra-N-butylammonium cation. The formation of [Mg(THF)6]2+, [Mg2-Cl)3(THF)6]+ and [MgCl4]2− ions . Journal of Organometallic Chemistry . July 1985 . 290 . 1 . c1–c3 . 10.1016/0022-328X(85)80155-8.
7. Book: Muetterties . Earl L. . The Chemistry of Boron and Its Compounds . 1967 . Wiley . 978-0-471-62350-2 . 336–337 . en.
8. Book: Evaluation of Room-Temperature Chloroaluminate Molten Salts as Electrolytes for High Energy Density Batteries . 1990 . Defense Technical Information Center . en.
9. Book: Ramsden . Eileen . Barker . Ray . Barsby . Darrel . Commons . Rob . Rizzo . Gez . Swales . Michala . Wood . Ian . Rounce . J. F. . Lowe . T. L. . Chambers . Joan Sybil . Crawshaw . D. J. . Jefferson . Brian . Bowles . David . Mullan . Eddie . Wiseman . Garry . Rayneau . John . Heylings . Mike . Wagner . Rob . Cavill . Steve . Beadsworth . Tony . Rourke . C. P. . Gaulter . Mark . Gaulter . Brian . Smedley . Robert . Cook . Ian . A-Level Chemistry . 8 October 2020 . OUP Oxford . 978-1-382-01786-2 . en.