Tetraiodomercurate(II) is an inorganic dianion that is found in potassium tetraiodomercurate(II), as well as various other salts. Tetraiodomercurate(II) has the chemical formula HgI2−4. The central mercury atom in this coordination complex has a +2 oxidation state. Although the complex has tetrahedral molecular geometry, its exact geometry can be influenced by hydrogen bonding to the iodine atoms.[1]

Salts

At room temperature, salts of tetraiodomercurate(II) come in various colors ranging from red to light yellow.[2]

Silver tetraiodomercurate(II) and copper tetraiodomercurate(II), Ag2HgI4 and Cu2HgI4 respectively, can be generated from the precursor potassium tetraiodomercurate(II) and are thermochromic.[3][2][4] Its indium, gold, thallium, rubidium, cesium, and lithium salts are not thermochromic.[5][unreliable source?]

The aqueous solution of its barium salt, barium tetraiodomercurate(II) [de] (BaHgI4), is known as Rohrbach's solution and has historically been used as a heavy liquid.[6][7]

References

  1. ↑ Terao, Hiromitsu; Gesing, Thorsten M.; Ishihara, Hideta; Furukawa, Yoshihiro; Gowda, B. Thimme (2009). "Bis(guanidinium) tetraiodidomercurate(II)". Acta Crystallographica Section e Structure Reports Online. 65 (5): m503. doi:10.1107/S160053680901280X. PMC 2977565. PMID 21583751.
  2. 1 2 Jaw, Huey-Rong C.; Mooney, Margaret M.; Novinson, Thomas; Kaska, William C.; Zink, Jeffrey I. (1987-05-01). "Optical properties of the thermochromic compounds Ag2HgI4 and Cu2HgI4". Inorganic Chemistry. 26 (9): 1387–1391. doi:10.1021/ic00256a011. ISSN 0020-1669.
  3. ↑ Raditoiu, Valentin; Radovici, Constantin; Raditoiu, Alina; Nicolae, Cristian Andi; Culita, Daniela Cristina; Fierascu, Radu Claudiu; Amariutei, Viorica; Wagner, Luminita Eugenia (2013-10-01). "Switching behavior of thermochromic copper and silver tetraiodomercurate embedded in silica hybrid materials". Optical Materials. 35 (12): 2565–2572. Bibcode:2013OptMa..35.2565R. doi:10.1016/j.optmat.2013.07.027. ISSN 0925-3467.
  4. ↑ Handbook of Preparative Inorganic Chemistry 1 & 2, Brauer.
  5. ↑ US4832933A, Novinson, Thomas, "Metal tetraiodomercurates as infrared detectors", issued 1989-05-23
  6. ↑ "Inorganic analysis". Analyst. 37 (433): 145–153. 1912-01-01. Bibcode:1912Ana....37..145.. doi:10.1039/AN9123700145. ISSN 1364-5528.
  7. ↑ Dictionary of Chemistry. ISBN 978-0-07-141046-5.
source: https://en.wikipedia.org/wiki/Tetraiodomercurate(II)