Sodium perchlorate

Its heat of formation is −382.75 kJ/mol, i.e. it is thermally stable up to high temperatures. At 490 °C it undergoes thermal decomposition, producing sodium chloride and dioxygen. {{cite journal|last1 = Devlin|first1 = D. J.|last2 = Herley|first2 = P. J.|date = 1987|title = Thermal decomposition and dehydration of sodium perchlorate monohydrate

|url = https://www.sciencedirect.com/science/article/pii/0168733687800190|journal = Reactivity of Solids|volume = 3|issue = 1–2|pages = 75–84|doi = 10.1016/0168-7336(87)80019-|doi-broken-date = 1 November 2024|access-date = 3 May 2023}}

It crystallizes in the rhombic crystal system.{{cite book|last=Eagleson|first=Mary|title=Concise Encyclopedia Chemistry|url=https://archive.org/details/conciseencyclope00eagl|url-access=registration|others=revised, illustrated|access-date=March 7, 2013|year=1994|publisher=Walter de Gruyter|isbn=978-3-11-011451-5|page=1000}}

Perchloric acid is made by treating {{chem2|NaClO4}} with HCl. Ammonium perchlorate and potassium perchlorate, of interest in rocketry and pyrotechnics, are prepared by double decomposition from a solution of sodium perchlorate and ammonium chloride or potassium chloride, respectively.

Because of its high solubility (2096 g/L at 25 °C) and the inert behaviour of dissolved perchlorate, solutions of {{chem2|NaClO4}} are often used as unreactive background electrolyte (supporting electrolyte). Indeed, because the reduction reaction of perchlorate is kinetically limited even if it is a thermodynamically unstable compound, perchlorate is a redox non-sensitive anion. It is also a non-complexing anion with a fairly low ligand binding capacity.

In the past perchlorates were quite widely used in the synthesis of coordination compounds because their larger size (compared to halides) and excellent hydrogen bonding abilities made them highly effective counter-ions for complexes with ammine, aquo and halido ligands, often yielding highly crystalline products. However because of the hazards (see Safety Section below) associated with their use they have been largely superseded in most labs by much less risky counterions like fluoroborate (BF₄^–, PF₆^– and related anions.

Sodium perchlorate is the precursor to ammonium, potassium and lithium perchlorate salts, often taking advantage of their low solubility in water relative to {{chem2|NaClO4}} (209 g/(100 mL) at 25 °C).{{cite journal |doi=10.1021/ic00081a014 |title=Linkage Isomerism in Cobalt(III) Pentaammine Complexes of 2-Pyridone |date=1994 |last1=Angus |first1=Patricia M. |last2=Jackson |first2=W. Gregory |journal=Inorganic Chemistry |volume=33 |issue=3 |pages=477–483 }}

It is used for denaturating proteins in biochemistry and in standard DNA extraction and hybridization reactions in molecular biology.

Sodium perchlorate can be used to block iodine uptake before administration of iodinated contrast agents in patients with subclinical hyperthyroidism (suppressed TSH).Becker, C. (2007, September). Radiologisch praxisrelevante prophylaxe und therapie von nebenwirkungen jodhaltiger kontrastmittel. [Prophylaxis and treatment of side effects due to iodinated contrast media relevant to radiological practice]. Der Radiologe. 47(9), 768–773. {{doi|10.1007/s00117-007-1550-4}}

Sodium perchlorate is produced by anodic oxidation of sodium chlorate ({{chem2|NaClO3}}) at an inert electrode, such as platinum.{{cite encyclopedia|author=Helmut Vogt |author2=Jan Balej |author3=John E. Bennett |author4=Peter Wintzer |author5=Saeed Akbar Sheikh |author6=Patrizio Gallone |title=Chlorine Oxides and Chlorine Oxygen Acids|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|date=2000 |publisher= Wiley-VCH|doi=10.1002/14356007.a06_483|isbn=3-527-30673-0 }}

:{{chem2|Na+ClO3− + H2O → Na+ClO4− + 2 H+ + 2 e−}} (acidic medium)

:{{chem2|Na+ClO3− + 2 OH− → Na+ClO4− + H2O + 2 e−}} (alkaline medium)

All perchlorates are potent oxidisers. When mixed with organic compounds extreme combustion reactions can result, hence the use of such materials in fireworks, low tech rocket propellants and improvised explosives. Because of their kinetic inertness mixtures of perchlorate with organic compounds can ignite/detonate spontaneously and be shock sensitive.

Acute toxicity: The median lethal dose (LD₅₀) is 2 – 4 g/kg (rabbits, oral).

Chronic toxicity: The frequent consumption of drinking water with low concentrations (in the range of μg/L, ppb) of perchlorate is harmful for the thyroid gland as the perchlorate anion competes with the uptake of iodide severely disrupting thyroid function.

Environmental effects: Perchlorate anions are regarded as persistent pollutants that can cause long term contamination of drinking water and NaClO4's high solubility makes it highly mobile in the environment. Significant concerns have been raised about the environmental impacts of perchlorates because of its ability to disrupt iodide uptake and metabolism.{{cite journal |last1=Sijimol |first1=M. J. |last2=Mohan |first2=Mahesh |title=Environmental impacts of perchlorate with special reference to fireworks—a review |journal=Environmental Monitoring and Assessment |date=2014 |volume=186 |issue=11 |pages=7203–7210 |doi=10.1007/s10661-014-3921-4 |pmid=25004859 |bibcode=2014EMnAs.186.7203S }}

• Potassium perchlorate

{{reflist}}

• [https://webbook.nist.gov/cgi/cbook.cgi?ID=C7601890 WebBook page for NaClO₄]

{{Sodium compounds}}

{{Perchlorates}}

Category:Perchlorates

Category:Sodium compounds

Category:Deliquescent materials