mercury(II) sulfate

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The anhydrous compound features Hg²⁺ in a highly distorted tetrahedral HgO₄ environment. Two Hg-O distances are 2.22 Å and the others are 2.28 and 2.42 Å.{{cite journal |doi=10.1524/zkri.1980.0011|title=A Reinvestigation of the Crystal Structures of HgSO₄ and CdSO₄|journal=Zeitschrift für Kristallographie - Crystalline Materials|year=1980|volume=153|issue=1–2|pages=121–129|bibcode=1980ZK....153..121A|last1=Aurivillius|first1=Karin|last2=Stålhandske|first2=Claes}} In the monohydrate, Hg²⁺ adopts a linear coordination geometry with Hg-O (sulfate) and Hg-O (water) bond lengths of 2.179 and 2.228 Å, respectively. Four weaker bonds are also observed with Hg---O distances >2.5 Å.{{cite journal |doi=10.1107/s0567740880002361|title=An X-ray and Neutron Diffraction Study of Mercury(II) Sulphate Monohydrate|year=1980|last1=Stålhandske|first1=C.|journal=Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry|volume=36|pages=23–26}}

In 1932, the Japanese chemical company Chisso Corporation began using mercury sulfate as the catalyst for the production of acetaldehyde from acetylene and water. Though it was unknown at the time, methylmercury is formed as a side product of this reaction. Exposure and consumption of the mercury waste products, including methylmercury, that were dumped into Minamata Bay by Chisso are believed to be the cause of Minamata disease in Minamata, Japan.[http://www.bu.edu/sustainability/minamata-disease/ Minamata Disease] {{webarchive |url=https://web.archive.org/web/20191113002620/http://www.bu.edu/sustainability/minamata-disease/ |date=13 November 2019}}. Boston University. Retrieved 2016-11-10.

Mercury sulfate can be produced

by treating mercury with hot concentrated sulfuric acid:{{cite book |doi=10.1002/14356007.a16_269.pub2|chapter=Mercury, Mercury Alloys, and Mercury Compounds|title=Ullmann's Encyclopedia of Industrial Chemistry|year=2006|last1=Simon|first1=Matthias|last2=Jönk|first2=Peter|last3=Wühl-Couturier|first3=Gabriele|last4=Halbach|first4=Stefan|isbn=3527306730}}

:{{chem2 | Hg + 2 H2SO4 -> HgSO4 + SO2 + 2 H2O }}

Alternatively yellow mercuric oxide reacts also with concentrated sulfuric acid.{{cite journal|last=Robey|first=R. F.|author2=Robertson, N. C.|title=Test for tert-Butyl and Isopropyl Alcohols with Deniges Reagent|journal=Analytical Chemistry|date=May 1947|volume=19|issue=5|pages=310–311|doi=10.1021/ac60005a007}}

An acidic solution of mercury sulfate is known as Denigés' reagent. It was commonly used throughout the 20th century as a qualitative analysis reagent. If Denigés' reagent is added to a solution containing compounds that have tertiary alcohols, a yellow or red precipitate will form.{{cite journal |last=Marks |first=E.M. |author2=Lipkin, D. |title=Reaction of Aliphatic Ethers with Denigés' Reagent |journal=J. Org. Chem. |year=1939 |volume=3 |issue=6 |pages=598–602 |doi=10.1021/jo01223a008}}

File:Rxn scheme for HgSO4 (cropped).png

Mercury sulfate, as well as other mercury(II) compounds, are commonly used as catalysts in oxymercuration-demercuration, a type of electrophilic addition reaction that results in hydration of an unsaturated compound. The hydration of an alkene gives an alcohol. The regioselectivity is that predicted by Markovnikov's rule. For an alkyne, the result is an enol, which tautomerizes to give the carbonyl.{{Cite book |last1=Clayden |first1=Jonathan |title=Organic chemistry |last2=Greeves |first2=Nick |last3=Warren |first3=Stuart |date=2012 |publisher=Oxford university press |isbn=978-0-19-927029-3 |edition=2nd |location=Oxford |pages=444–445}} At one time, this chemistry was employed commercially for the preparation of acetaldehyde from acetylene:{{cite book |doi=10.1002/14356007.a01_031.pub2 |chapter=Acetaldehyde |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2006 |last1=Eckert |first1=Marc |last2=Fleischmann |first2=Gerald |last3=Jira |first3=Reinhard |last4=Bolt |first4=Hermann M. |last5=Golka |first5=Klaus |isbn=978-3-527-30385-4 }}

:{{chem2|C2H2 + H2O -> CH3CHO}}

A related and specialized example is the conversion of 2,5-dimethylhexyne-2,5-diol to 2,2,5,5-tetramethyltetrahydrofuran using aqueous mercury sulfate without the addition of acid.{{cite journal|last=Wasacz|first=J. P.|author2=Badding, V. G.|title=A hydration of an alkyne illustrating steam and vacuum distillation|journal=Journal of Chemical Education|year=1982|volume=59|issue=8|page=694|doi=10.1021/ed059p694|bibcode=1982JChEd..59..694W}}

Inhalation of HgSO₄ can result in acute poisoning: causing tightness in the chest, difficulties breathing, coughing and pain. Exposure of HgSO₄ to the eyes can cause ulceration of conjunctiva and cornea. If mercury sulfate is exposed to the skin it may cause sensitization dermatitis. Lastly, ingestion of mercury sulfate will cause necrosis, pain, vomiting, and severe purging. Ingestion can result in death within a few hours due to peripheral vascular collapse.

It was used in the late 19th century to induce vomiting for medical reasons.{{Cite journal |last=Hubbard |date=1846-06-24 |title=On the Effects of the Sub-Sulphate of Mercury, (Turpeth Mineral,) As An Emetic |journal=BMJ |language=en |volume=s1-10 |issue=25 |pages=288–289 |doi=10.1136/bmj.s1-10.25.288 |issn=0959-8138 |pmc=2559525 |pmid=20794001}}

• {{cite journal | title =The role of mercury salts in the catalytic transformation of acetylene into acetaldehyde, and a new commercial process for manufacture of paraaldehyde | author1=Vogt, R | author2= Nieuwland, J | journal = J. Am. Chem. Soc. | volume = 43 | issue = 9 | pages=2071–81 | date=September 1921 | doi = 10.1021/ja01442a010| url=https://zenodo.org/record/1428816 }}

{{reflist|30em}}

{{Commons category|Mercury(II) sulfate}}

• [https://web.archive.org/web/20060425193836/http://www.npi.gov.au/database/substance-info/profiles/53.html National Pollutant Inventory – Mercury and compounds Fact Sheet]
• [https://www.cdc.gov/niosh/npg/npgd0383.html NIOSH Pocket Guide to Chemical Hazards]

{{Mercury compounds}}

{{Sulfates}}

{{sulfur compounds}}

Category:Sulfates

Category:Mercury(II) compounds