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| {{chembox
| | 38 year-old Engineering Specialists Greg Chavous from La Malbaie, has hobbies for example r/c cars, new launch property singapore and ornithology. that covered taking a trip to National History Park – Citadel.<br><br>Feel free to surf to my blog post - [http://stage.meclub.com/content/singapore-govt-condominium The Skywoods condo video] |
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| | Name = Sulfamic acid
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| | ImageFile = Zwitterion Structural Formulae V.1.svg
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| | ImageSize = 220px
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| | ImageName = Tautomerism of sulfamic acid
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| | ImageFileL1 = Sulfamic_acid.png
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| | ImageSizeL1 = 110px
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| | ImageNameL1 = Ball-and-stick model of the canonical neutral form
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| | ImageFileR1 = Sulfamic acid zwitterion stick ball.png
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| | ImageSizeR1 = 110px
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| | ImageNameR1 = Ball-and-stick model of the zwitterionic form
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| | ImageFile2 = Sample of sulfamic acid.jpg
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| | ImageSize2 = 250px
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| | IUPACName = Sulfamic acid
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| | Section1 = {{Chembox Identifiers
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| | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
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| | ChemSpiderID = 5767
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| | PubChem = 5987
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| | InChI = 1/H3NO3S/c1-5(2,3)4/h(H3,1,2,3,4)
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| | InChIKey = IIACRCGMVDHOTQ-UHFFFAOYAK
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| | ChEBI_Ref = {{ebicite|correct|EBI}}
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| | ChEBI = 9330
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| | SMILES = O=S(=O)(O)N
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| | ChEMBL_Ref = {{ebicite|correct|EBI}}
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| | ChEMBL = 68253
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| | StdInChI_Ref = {{stdinchicite|correct|chemspider}}
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| | StdInChI = 1S/H3NO3S/c1-5(2,3)4/h(H3,1,2,3,4)
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| | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
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| | StdInChIKey = IIACRCGMVDHOTQ-UHFFFAOYSA-N
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| | CASNo = 5329-14-6
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| | CASNo_Ref = {{cascite|correct|CAS}}
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| | UNNumber = 2967
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| | EINECS = 226-218-8
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| | RTECS = WO5950000
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| }}
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| | Section2 = {{Chembox Properties
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| | Formula = H<sub>3</sub>NSO<sub>3</sub>
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| | MolarMass = 97.10 g/mol
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| | Appearance = white crystals
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| | MeltingPt = 205 °C decomp.
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| | Density = 2.15 g/cm<sup>3</sup>
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| | Solubility = moderate, with slow hydrolysis
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| | pKa = 1.0<ref>{{cite doi|10.1039/JR9600004236}}</ref>
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| }}
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| | Section7 = {{Chembox Hazards
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| | ExternalMSDS = [http://www.inchem.org/documents/icsc/icsc/eics0328.htm ICSC 0328]
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| | EUIndex = 016-026-00-0
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| | EUClass = Irritant ('''Xi''')
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| | RPhrases = {{R36/38}} {{R52/53}}
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| | SPhrases = {{S2}} {{S26}} {{S28}} {{S61}}
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| | NFPA-H =
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| | NFPA-F =
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| | NFPA-R =
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| | NFPA-O =
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| | FlashPt =
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| }}
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| | Section8 = {{Chembox Related
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| | OtherAnions =
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| | OtherCations = [[Ammonium sulfamate]]
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| | OtherFunctn =
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| | Function =
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| | OtherCpds =
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| }}
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| }}
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| '''Sulfamic acid''', also known as '''amidosulfonic acid''', '''amidosulfuric acid''', '''aminosulfonic acid''', and '''sulfamidic acid''', is a molecular compound with the formula H<sub>3</sub>NSO<sub>3</sub>. This colorless, water-soluble compound finds many applications. Sulfamic acid melts at 205 °C before decomposing at higher temperatures to H<sub>2</sub>O, SO<sub>3</sub>, SO<sub>2</sub>, and N<sub>2</sub>.<ref name ="kirk-othmer">{{cite doi|10.1002/0471238961.1921120625151908.a01}}</ref>
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| Sulfamic acid (H<sub>3</sub>NSO<sub>3</sub>) may be considered an intermediate compound between [[sulfuric acid]] (H<sub>2</sub>SO<sub>4</sub>), and [[sulfamide]] (H<sub>4</sub>N<sub>2</sub>SO<sub>2</sub>), effectively - though see [[#Structure and reactivity|below]] - replacing an -OH group with an -NH<sub>2</sub> group at each step. This pattern can extend no further in either direction without breaking down the -SO<sub>2</sub> group. '''Sulfamates''' are derivatives of sulfamic acid.
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| ==Production==
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| Sulfamic acid is produced industrially by treating [[urea]] with a mixture of [[sulfur trioxide]] and [[sulfuric acid]] (or [[oleum]]). The conversion is conducted in two stages:
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| :OC(NH<sub>2</sub>)<sub>2</sub> + SO<sub>3</sub> → OC(NH<sub>2</sub>)(NHSO<sub>3</sub>H)
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| :OC(NH<sub>2</sub>)(NHSO<sub>3</sub>H) + H<sub>2</sub>SO<sub>4</sub> → CO<sub>2</sub> + 2 H<sub>3</sub>NSO<sub>3</sub>
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| In this way, approximately 96,000 tons were produced in 1995.<ref>A. Metzger "Sulfamic Acid" in Ullmann's Encyclopedia of Industrial Chemistry, 2012, Wily-VCH, Weinheim. {{DOI|10.1002/14356007.a25_439}}</ref>
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| ==Structure and reactivity==
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| The compound is well described by the formula H<sub>3</sub>NSO<sub>3</sub>, not the [[tautomer]] H<sub>2</sub>NSO<sub>2</sub>(OH). The relevant bond distances are S=O, 1.44 and S-N 1.77 [[Ångström|Å]]. The greater length of the S-N distance is consistent with a single bond.<ref>{{cite doi|10.1107/S0567740877002568}}</ref> Furthermore, a [[neutron diffraction]] study located the hydrogen atoms, all three of which are 1.03 [[Ångström|Å]] distant from nitrogen.<ref name="Sass">{{cite doi|10.1107/S0365110X60000789}}</ref> In the solid state, the molecule of sulfamic acid is well described by a [[zwitterion]]ic form :
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| {|align="center" class="wikitable"
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| |<center>[[File:Sulfamic-acid-from-xtal-3D-balls.png|150px]]</center>
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| |-
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| |<center>[[Ball-and-stick model]] of a sulfamic<br>acid zwitterion in the crystal<ref name="Sass" /></center>
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| |}
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| Water solutions are unstable and slowly hydrolyze to [[ammonium bisulfate]], but the crystalline solid is indefinitely stable under ordinary storage conditions. Its behavior resembles that of [[urea]], (H<sub>2</sub>N)<sub>2</sub>CO. Both feature [[amino group]]s linked to electron-withdrawing centers that can participate in [[delocalized bond]]ing. Both liberate [[ammonia]] upon heating in water.
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| ===Acid-base reactions===
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| Sulfamic acid is a moderately strong acid, ''K''<sub>a</sub> = 1.01 x 10<sup>−1</sup>. Because the solid is non-[[hygroscopic]], it is used as a standard in [[acidimetry]] (quantitative assays of acid content).
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| :H<sub>3</sub>NSO<sub>3</sub> + NaOH → NaH<sub>2</sub>NSO<sub>3</sub> + H<sub>2</sub>O
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| Double deprotonation can be effected in [[ammonia|NH<sub>3</sub>]] solution to give [HNSO<sub>3</sub>]<sup>2−</sup>.<ref name ="L.B. Clapp">{{cite doi|10.1021/ed020p189}}</ref>
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| :H<sub>3</sub>NSO<sub>3</sub> + 2 NH<sub>3</sub> → [HNSO<sub>3</sub>]<sup>2−</sup> + 2 [NH<sub>4</sub>]<sup>+</sup>
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| ===Reaction with nitric and nitrous acids===
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| With [[nitrous acid|HNO<sub>2</sub>]], sulfamic acid reacts to give [[nitrogen|N<sub>2</sub>]], while with [[nitric acid|HNO<sub>3</sub>]], it affords [[nitrous oxide|N<sub>2</sub>O]].
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| :HNO<sub>2</sub> + H<sub>3</sub>NSO<sub>3</sub> → H<sub>2</sub>SO<sub>4</sub> + N<sub>2</sub> + H<sub>2</sub>O
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| :HNO<sub>3</sub> + H<sub>3</sub>NSO<sub>3</sub> → H<sub>2</sub>SO<sub>4</sub> + N<sub>2</sub>O + H<sub>2</sub>O
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| ===Reaction with hypochlorite===
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| The reaction of excess [[hypochlorite]] with sulfamic acid or a sulfamate salt gives rise reversibly to both N-chlorosulfamate and N,N-dichlorosulfamate.<ref>{{cite patent|US|3328294}}</ref><ref>{{cite patent|FR|2087248}}</ref><ref>{{cite doi|10.1021/cr60324a002}}</ref>
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| :HClO + H<sub>2</sub>NSO<sub>3</sub>H → ClNHSO<sub>3</sub>H + H<sub>2</sub>O
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| :HClO + ClNHSO<sub>3</sub>H <math>\rightleftarrows</math> Cl<sub>2</sub>NSO<sub>3</sub>H + H<sub>2</sub>O
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| Consequently sulfamic acid is used as hypochlorite scavenger in the oxidation of [[aldehydes]] with [[chlorite]] such as the [[Pinnick oxidation]].
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| ==Applications==
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| Sulfamic acid is mainly a precursor to sweet-tasting compounds. Reaction with [[cyclohexylamine]] followed by addition of [[sodium hydroxide|NaOH]] gives C<sub>6</sub>H<sub>11</sub>NHSO<sub>3</sub>Na, [[sodium cyclamate]]. Related compounds are also [[sweetener]]s, see [[acesulfame potassium]].
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| Sulfamates have been used in the design of many types of therapeutic agents such as [[antibiotic]]s, nucleoside/nucleotide [[human immunodeficiency virus]] (HIV) [[reverse transcriptase inhibitor]]s, [[HIV protease inhibitor]]s (PIs), anti-cancer drugs ([[steroid sulfatase]] and [[carbonic anhydrase]] inhibitors), anti-[[epilepsy|epileptic]] drugs, and [[weight loss drug]]s.<ref>{{cite doi|10.1002/med.20021}}</ref>
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| ===Cleaning agent===
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| Sulfamic acid is used as an acidic [[cleaning agent]], sometimes pure or as a component of proprietary mixtures, typically for [[metal]]s and [[ceramic]]s. It is frequently used for removing [[rust]] and [[limescale]], replacing the more volatile and irritating [[hydrochloric acid]], which is however cheaper. It is often a component of household [[descaling agent]]s, for example, Lime-A-Way Thick Gel contains up to 8% sulfamic acid and pH 2 - 2.2,<ref>{{cite web |url= http://www.hardwarestore.com/media/msds/125835.pdf|title= Material Safety Data Sheet - Lime-A-Way Lime, Calcium and Rust Cleaner (Trigger Spray)|last=Benckiser |first=Reckitt|work= hardwarestore.com|accessdate= 17 November 2011}}</ref> or [[detergent]]s used for removal of [[limescale]]. When compared to most of the common strong mineral acids, sulfamic acid has desirable water descaling properties, low volatility, low toxicity. It forms water-soluble salts of calcium and ferric iron.
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| Importantly, sulfamic acid is preferable to use in household in comparison to hydrochloric acid for its intrinsic safety. If erroneously mixed with hypochlorite based products such as [[bleach]], it does not form [[chlorine]] gas, where the most common acids would; the reaction ([[Neutralization (chemistry)|neutralization]]) with [[ammonia|NH<sub>3</sub>]], produces a salt as depicted in the section above.
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| Its also finds applications in the industrial cleaning of dairy and brew-house equipment. Although it is considered less corrosive than [[hydrochloric acid]], [[corrosion inhibitor]]s are often added to commercial cleansers of which it is a component. Some of its domestic use, e.g. [[Easy-Off]], for descaling include home coffee and espresso equipment and in denture cleaners.
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| ===Other uses===
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| * [[Catalyst]] for [[esterification]] process
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| * [[Dye]] and [[pigment]] manufacturing
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| * [[Herbicide]]
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| * Coagulator for [[urea-formaldehyde resin]]s
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| * Ingredient in [[fire retardant|fire extinguishing media]]. Sulfamic acid is the main raw material for [[ammonium sulfamate]] which is a widely used herbicide and fire retardant material for household product.
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| * Pulp and paper industry as a chloride stabilizer
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| * Synthesis of [[nitrous oxide]] by reaction with nitric acid
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| * The deprotonated form (sulfamate) is a common counterion for nickel(II) in [[electroplating]].
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| ===Silver polishing===
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| According to the label on the consumer product, the liquid silver cleaning product ''TarnX ''contains [[thiourea]], a [[detergent]], and sulfamic acid.
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| ==References==
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| {{reflist}}
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| ==External links==
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| * {{cite web |url= http://www.osha.gov/dts/chemicalsampling/data/CH_268428.html|title= Chemical Sampling Information - Sulfamic Acid|first= |last= |author= |authorlink= |coauthors= |date= 6 May 1997|work= |publisher= Occupational Health & Safety Administration|accessdate= 17 November 2011}}
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| * {{cite book |last1= Cremlyn|first1= R.J.|title= An Introduction to Organosulfur Chemistry|year= 1996|publisher= John Wiley and Sons|location= Chichester|isbn= 978-0-471-95512-2}}
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| * {{Greenwood&Earnshaw}}
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| {{Commons category|Sulfamic acid}}
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| {{Hydrogen compounds}}
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| {{DEFAULTSORT:Sulfamic Acid}}
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| [[Category:Hydrogen compounds]]
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| [[Category:Sulfur oxoacids]]
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| [[Category:Household chemicals]]
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| [[Category:Cleaning product components]]
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| [[Category:Sulfamates]]
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