View source for Indium(III) sulfate

{{chembox
| Watchedfields = changed
| verifiedrevid = 441619171
| Name = Indium(III) sulfate
| ImageFile =
| ImageName = Indium(III) sulfate
| OtherNames = Indium sulfate
|Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 24258
| PubChem = 26044
| RTECS = NL1925000
| InChI = 1/2In.3H2O4S/c;;3*1-5(2,3)4/h;;3*(H2,1,2,3,4)/q2*+3;;;/p-6
| InChIKey = XGCKLPDYTQRDTR-CYFPFDDLAA
| SMILES = [In+3].[In+3].[O-]S(=O)(=O)[O-].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/2In.3H2O4S/c;;3*1-5(2,3)4/h;;3*(H2,1,2,3,4)/q2*+3;;;/p-6
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = XGCKLPDYTQRDTR-UHFFFAOYSA-H
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 13464-82-9
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 514CE39CG4
| EINECS = 236-689-1
  }}
|Section2={{Chembox Properties
| Formula = In<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>
| MolarMass = 517.81 g/mol
| Appearance = white-gray odorless powder, [[hygroscopic]], monoclinic crystals
| Density = 3.44 g/cm<sup>3</sup>, solid
| Solubility = soluble, (539.2 g/L at 20&nbsp;°C)<ref>[http://www.indium.com/_dynamo/download.php?docid=153 Indium Sulfate. Product Data Sheet] {{Webarchive|url=https://web.archive.org/web/20120210100836/http://www.indium.com/_dynamo/download.php?docid=153 |date=10 February 2012 }} ''Indium Cooperation''</ref>
| MeltingPt = decomposes at 600&nbsp;°C<ref>Perry D, Phillips S (1995) [https://books.google.com/books?id=0fT4wfhF1AsC ''Handbook of Inorganic Compounds]: Version 2.0, An Electronic Database'', CRC Press {{ISBN|0-8493-8671-3}}</ref>
| BoilingPt =
  }}
|Section3={{Chembox Structure
| CrystalStruct = monoclinic (room temperature)
| SpaceGroup = P12<sub>1</sub>
| PointGroup =
| LattConst_a = 8.57&nbsp;Å<ref name=vil>{{cite book|last1=Villars|first1=Pierre|last2=Cenzual|first2=Karin|last3=Gladyshevskii|first3=Roman|title=Handbook of Inorganic Substances 2015|date=2015|publisher=Walter de Gruyter|page=654|url=https://books.google.com/books?id=DSp1BgAAQBAJ|isbn=9783110311747}}</ref>
| LattConst_b = 8.908&nbsp;Å
| LattConst_c = 14.66&nbsp;Å
| LattConst_alpha =
| LattConst_beta = 124.72
| LattConst_gamma =
| Coordination =
  }}
|Section4={{Chembox Structure
| CrystalStruct = rhombohedral
| SpaceGroup = R-3
| PointGroup =
| LattConst_a = 8.44&nbsp;Å<ref name=vil/><ref name=pall13>{{cite journal|last1=Pallister|first1=Peter J.|last2=Moudrakovski|first2=Igor L.|last3=Enright|first3=Gary D.|last4=Ripmeester|first4=John A.|title=Structural assessment of anhydrous sulfates with high field 33S solid state NMR and first principles calculations|journal=CrystEngComm|date=2013|volume=15|issue=43|pages=8808|doi=10.1039/C3CE41233D}}</ref>
| LattConst_b = 8.44&nbsp;Å
| LattConst_c = 23.093&nbsp;Å
| LattConst_alpha =
| LattConst_beta =
| LattConst_gamma = 120
| Coordination = 6 formula per cell
  }}
|Section5={{Chembox Thermochemistry
| DeltaGf =
| DeltaHc =
| DeltaHf =
| Entropy =
| HeatCapacity = 0.129<ref name=Nilson880>{{cite journal|last1=Nilson|first1=L. F.|last2=Pettersson|first2=Otto|title=On the Molecular Heat and Volume of the Rare Earths and Their Sulphates|journal=Proceedings of the Royal Society of London|date=1 January 1880|volume=31|issue=206–211|pages=46–51|doi=10.1098/rspl.1880.0005|bibcode=1880RSPS...31...46N|doi-access=free}}</ref>
  }}
|Section7={{Chembox Hazards
| ExternalSDS = [http://tttmetalpowder.com/wp-content/uploads/2012/12/Indium-Sulfate-Powder-801-MSDS.pdf tttmetalpowder]
| NFPA-H = 2
| NFPA-R = 0
| NFPA-F = 0
| NFPA_ref = <ref>{{cite web|url=https://www.pfaltzandbauer.com/SDSFile.ashx?ItemCode=I01140|title=Sfety Data Sheet Indium sulfate anhydrous 99.99%|publisher=Pfaltz & Bauer, Inc.|access-date=14 November 2017|archive-date=28 March 2022|archive-url=https://web.archive.org/web/20220328081801/https://www.pfaltzandbauer.com/SDSFile.ashx?ItemCode=I01140|url-status=dead}}</ref>
| PEL = 0.1<ref name=tr>{{cite web|author1=Tritrust Industrial C. Ltd.|title=MSDS OF Indium Sulfate|url=http://tttmetalpowder.com/wp-content/uploads/2012/12/Indium-Sulfate-Powder-801-MSDS.pdf|access-date=31 May 2015|archive-url=https://web.archive.org/web/20160304073452/http://tttmetalpowder.com/wp-content/uploads/2012/12/Indium-Sulfate-Powder-801-MSDS.pdf|archive-date=4 March 2016|url-status=dead}}</ref>
| TLV-TWA = 0.1<ref name=tr/>
| TLV-STEL = 0.3<ref name=tr/>
| GHSPictograms = {{GHS07}}
| GHSSignalWord= Warning
| HPhrases = {{H-phrases|315|319|335}}
| PPhrases = {{P-phrases|261|264|271|280|302+352|304+340|305+351+338|312|321|332+313|337+313|362|403+233|405|501}}
  }}
}}

'''Indium(III) sulfate''' (In<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>) is a [[sulfate]] salt of the metal [[indium]]. It is a sesquisulfate, meaning that the sulfate group occurs 1{{half}} times as much as the metal. It may be formed by the reaction of [[indium]], its [[indium(III) oxide|oxide]], or its carbonate with [[sulfuric acid]]. An excess of strong acid is required, otherwise insoluble basic salts are formed.<ref name=hes63/> As a solid indium sulfate can be [[anhydrous]], or take the form of a [[Hydrate|pentahydrate]] with five water molecules<ref name=Perret74/> or a nonahydrate with nine molecules of water. Indium sulfate is used in the production of indium or indium containing substances. Indium sulfate also can be found in basic salts, acidic salts or double salts including '''indium alum'''.

==Properties==
In water solution, the indium ion forms a complex with water and sulfate, examples being In(H<sub>2</sub>O)<sub>5</sub>(SO<sub>4</sub>)<sup>+</sup> and In(H<sub>2</sub>O)<sub>4</sub>(SO<sub>4</sub>)<sub>2</sub><sup>−</sup>.<ref name=cam81>{{cite journal|last1=Caminiti|first1=R.|last2=Paschina|first2=G.|title=An X-ray diffraction study of the structure of the aqua indium(III) ion in indium sulphate solution|journal=Chemical Physics Letters|date=September 1981|volume=82|issue=3|pages=487–491|doi=10.1016/0009-2614(81)85425-5|bibcode=1981CPL....82..487C}}</ref><ref name=cw>{{cite book|last1=Cotton|first1=F. Albert|last2=Wilkinson|first2=Geoffrey|title=Advanced Inorganic Chemistry|date=1966|publisher=John Wiley & Sons|page=438}}</ref> Indium is unusual in forming a sulfate complex. The effect on the sulfate ion is revealed in the [[Raman spectrum]].<ref name=hes63>{{cite journal|last1=Hester|first1=Ronald E.|last2=Plane|first2=Robert A.|last3=Walrafen|first3=George E.|title=Raman Spectra of Aqueous Solutions of Indium Sulfate, Nitrate, and Perchlorate|journal=The Journal of Chemical Physics|date=1963|volume=38|issue=1|pages=249|doi=10.1063/1.1733470|bibcode=1963JChPh..38..249H}}</ref> The proportion of sulfate complex increases with temperature showing the reaction that forms it is endothermic.  The proportion also increases with concentration of the solution and can be over a half.<ref name=Rud004/> The sulfate complex rapidly exchanges with water at a rate of over 10,000,000 per second, so that [[Nuclear magnetic resonance|NMR]] cannot detect the difference that results from a complexed and noncomplexed indium ion.<ref name=Rud004/> An indium sulfate water solution is quite acidic with a 0.14&nbsp;mol/liter solution having a pH of 1.85. If the pH rises above 3.4 then a precipitate will form.<ref>{{cite book|last1=Busev|first1=A.I.|title=The Analytical Chemistry of Indium|date=22 October 2013|publisher=Elsevier|page=30|url=https://books.google.com/books?id=pVf9BAAAQBAJ&pg=PA5|isbn=9781483149554}}</ref>

The Raman spectrum of the solution shows lines at 650, 1000 and 1125&nbsp;cm<sup>−1</sup> due to a sulfur–oxygen bonds in sulfate bound to indium. A line at 255&nbsp;cm<sup>−1</sup> is due to the indium-oxygen bond to the sulfate. The water attached to the indium atom causes a band at about 400&nbsp;cm<sup>−1</sup>.<ref name=hes63/>

Solid [[anhydrous]] indium sulfate has two crystalline forms. When formed by chlorine gas [[Chemical transport reaction|chemical transport]] at 848 K, it has a monoclinic form with unit cell dimensions a = 8.570&nbsp;Å, b = 8.908&nbsp;Å and c = 12.0521&nbsp;Å, β = 91.05°, and four formulae per cell. A high temperature form deposited at 973K has a hexagonal (or rhombohedral) form with cell dimensions of a = 8.440&nbsp;Å, c = 23.093&nbsp;Å and six formulae per cell.<ref name=Krause95>{{cite journal|last1=Krause|first1=M.|last2=Gruehn|first2=R.|title=Contributions on the thermal behaviour of sulphates XVII. Single crystal structure refinements of In2(SO4)3 and Ga2(SO4)3|journal=Zeitschrift für Kristallographie|date=January 1995|volume=210|issue=6|pages=427–431|doi=10.1524/zkri.1995.210.6.427|bibcode=1995ZK....210..427K}}</ref>

During extraction of indium, a sulfate solution of mixed metals, including indium sulfate, has trivalent metals partitioned into a kerosene solution of di-2-ethylhexyl hydrogen phosphate. Isododecylphosphetanic and diisooctylphosphinic acids can also be used for this function.  The kerosene mixture is then backwashed with an acid to recover the metals in a water solution and regenerate the extracting fluid.<ref name=Trav004>{{cite journal|last1=Travkin|first1=V. F.|last2=Kubasov|first2=V. L.|last3=Glubokov|first3=Yu. M.|last4=Busygina|first4=N. S.|last5=Kazanbaev|first5=L. A.|last6=Kozlov|first6=P. A.|title=Extraction of indium(III) from sulfate solutions with organophosphorus acids|journal=Russian Journal of Applied Chemistry|date=October 2004|volume=77|issue=10|pages=1613–1617|doi=10.1007/s11167-005-0082-9|s2cid=94902567}}</ref>

==Production==

Indium metal reacts with cold concentrated sulfuric acid to produce Indium sulfate and hydrogen gas. If hot concentrated sulfuric acid is used indium will reduce the sulfuric acid to sulfur dioxide.<ref>{{cite journal |last1=Geckler |first1=Robert P. |last2=Marchi |first2=Louis E. |title=Indium |journal=Journal of Chemical Education |date=August 1944 |volume=21 |issue=8 |pages=407 |doi=10.1021/ed021p407|bibcode=1944JChEd..21..407G }}</ref>

Indium sulfate can also be produced from a reaction of sulfuric acid on indium oxide, indium carbonate, or indium hydroxide.

==Reactions==
When heated to {{convert|710|K|C}} or above, indium sulfate decomposes by giving off sulfur trioxide vapour, yielding indium oxide.<ref name=Zhou999>{{cite journal|last1=Zhou|first1=Huijuan|last2=Cai|first2=Weiping|last3=Zhang|first3=Lide|title=Synthesis and structure of indium oxide nanoparticles dispersed within pores of mesoporous silica|journal=Materials Research Bulletin|date=April 1999|volume=34|issue=6|pages=845–849|doi=10.1016/S0025-5408(99)00080-X}}</ref>

:<chem>In2(SO4)3 -> In2O3 + 3SO3</chem>

Alkalis added to indium sulfate solutions precipitate basic salts. For example, [[potassium hydroxide]] produces either a basic sulfate, 2In<sub>2</sub>O<sub>3</sub>.SO<sub>3</sub>·''n''H<sub>2</sub>O, or KIn<sub>3</sub>(OH)<sub>6</sub>(SO<sub>4</sub>)<sub>2</sub> depending on pH.<ref>{{cite journal|last1=Grimes|first1=S. M.|title=Chapter 4. Al, Ga, In, Tl|journal=Annual Reports on the Progress of Chemistry, Section A|date=1984|volume=81|page=90|doi=10.1039/IC9848100075}}</ref> [[Sodium pyrophosphate]] causes a slimy precipitate of indium pyrophosphate, In<sub>4</sub>(P<sub>2</sub>O<sub>7</sub>)<sub>3</sub>·3H<sub>2</sub>O. [[Potassium periodate]] causes a precipitate of a basic indium periodate, 2InO<sub>5</sub>·In(OH)<sub>3</sub>·6H<sub>2</sub>O .<ref>{{cite book|last1=Busev|first1=A.I.|title=The Analytical Chemistry of Indium|date=22 October 2013|publisher=Elsevier|pages=67–68|url=https://books.google.com/books?id=pVf9BAAAQBAJ&pg=PA67|isbn=9781483149554}}</ref> [[Oxalic acid]] causes a precipitate of indium oxalate, In<sub>2</sub>(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>·10H<sub>2</sub>O. Alkali oxalates cause a precipitate of the alkali dioxalatoindate to form MIn(C<sub>2</sub>O<sub>4</sub>)<sub>2</sub>·3H<sub>2</sub>O, where M = Na, K or NH<sub>4</sub>.<ref>{{cite book|last1=Busev|first1=A.I.|title=The Analytical Chemistry of Indium|date=22 October 2013|publisher=Elsevier|pages=111–112|url=https://books.google.com/books?id=pVf9BAAAQBAJ&pg=PA111|isbn=9781483149554}}</ref>

==Related compounds==
===Hydrogen sulfates===
An acid sulfate, indium hydrogensulfate tetrahydrate with the formula HIn(SO<sub>4</sub>)<sub>2</sub>·4H<sub>2</sub>O crystallises in the orthorhombic system with unit cell dimensions a = 9.997&nbsp;Å, b = 5.477&nbsp;Å, c = 18.44&nbsp;Å, with four of the formula per cell. The density is 2.50&nbsp;cm<sup>−3</sup>. In the acid sulfate, two water molecules are linked to the indium atom and a [[hydronium ion]] H<sub>5</sub>O<sub>2</sub> takes care of the proton. This is part of an acid sulfate family that includes Al, Ga, In, Tl(III), Fe(III) and Ti(III). HIn(SO<sub>4</sub>)<sub>2</sub> is made by evaporating an indium sulfate in 40% sulfuric acid solution<ref name=Tudo79>{{cite journal|last1=Tudo|first1=J.|last2=Jolibois|first2=B.|last3=Laplace|first3=G.|last4=Nowogrocki|first4=G.|last5=Abraham|first5=F.|title=Structure cristalline du sulfate acide d'indium(III) hydraté|journal=Acta Crystallographica Section B|date=15 July 1979|volume=35|issue=7|pages=1580–1583|doi=10.1107/s0567740879007172|bibcode=1979AcCrB..35.1580T |language=fr}}</ref> or cooling indium sulfate in a 60% sulfuric acid solution.<ref name=Voropaeva007>{{cite journal|last1=Voropaeva|first1=E. Yu.|last2=Stenina|first2=I. A.|last3=Yaroslavtsev|first3=A. B.|title=Proton conduction in indium hydrogensulfate and hydrous zirconia composites|journal=Russian Journal of Inorganic Chemistry|date=January 2007|volume=52|issue=1|pages=1–6|doi=10.1134/S0036023607010019|s2cid=96716246}}</ref> As the acid tetrahydrate is heated it gives off water yielding a trihydrate, monohydrate, and an anhydrous form at 370, 385 and 482K. Above 505K it gives out more water and [[sulfur dioxide]] yielding the neutral indium sulfate.<ref name=Voropaeva007/> Indium hydrogensulfate is a [[proton conductor]] with conductivity 0.0002Ω<sup>−1</sup>cm<sup>−1</sup>.<ref name=Voropaeva007/>

===Basic sulfates===
A basic indium sulfate is made by adding ethanol to a water solution of indium sulfate. Crystals can be formed by using a 0.05 molar solution with twice the volume of ethanol, and waiting for several weeks for crystals to form.<ref name="Johanss61">{{cite journal|last1=Johansson|first1=Georg|title=The Crystal Structure of <math chem>\scriptstyle\ce{InOHSO4(H2O)2}</math>|journal=Acta Chemica Scandinavica|date=1961|volume=15|issue=7|pages=1437–1453|url=http://actachemscand.dk/pdf/acta_vol_15_p1437-1453.pdf|access-date=31 May 2015|doi=10.3891/acta.chem.scand.15-1437|doi-access=free}}</ref> InOHSO<sub>4</sub>·(H<sub>2</sub>O)<sub>2</sub> has monoclinic crystals with a=6.06&nbsp;Å b=7.89&nbsp;Å c=12.66&nbsp;Å and β=107.5°. Cell volume is 577.6&nbsp;Å<sup>3</sup>.<ref name=Johanss61/> Another basic indium sulfate InOHSO<sub>4</sub> with rhombohedral crystals is made by heating an indium sulfate solution at 160&nbsp;°C or over for about a week in a sealed tube.<ref name=Johanss62>{{cite journal|last1=Johansson|first1=Georg|title=The Crystal Structure of FeOHSO4 and InOHSO4|journal=Acta Chemica Scandinavica|date=1962|volume=16|issue=5|pages=1234–1244|url=http://actachemscand.org/pdf/acta_vol_16_p1234-1244.pdf|access-date=31 May 2015|doi=10.3891/acta.chem.scand.16-1234|doi-access=free}}</ref> This insoluble basic salt also forms if indium sulfate solution is diluted below 0.005 molar. So a precipitate forms from diluted solutions as well as from heated solutions.<ref name=Rud004/>

===Anhydrous double sulfates===
Two different types of anhydrous double indium sulfates have been made. One is from the family M{{Sup sub|I|3}}M<sup>III</sup>(XO<sub>4</sub>)<sub>3</sub>, with M<sup>I</sup> being a large singly positive ion such as K, Rb, Cs, Tl or NH<sub>3</sub>; M<sup>III</sup> is triply charged and can be Al, Ga, In, Tl, V, Cr, Fe, Sc and other rare earths; and X is S or Se.<ref name=Joli80>{{cite journal|last1=Jolibois|first1=B.|last2=Laplace|first2=G.|last3=Abraham|first3=F.|last4=Nowogrocki|first4=G.|title=The low-temperature forms of some M1/3MIII(XO4)3 compounds: structure of triammonium indium(III) trisulfate|journal=Acta Crystallographica Section B|date=15 November 1980|volume=36|issue=11|pages=2517–2519|doi=10.1107/S0567740880009338|bibcode=1980AcCrB..36.2517J }}</ref> Most of these have a [[rhombohedral]] crystal structure.  However, triammonium indium trisulfate, (NH<sub>4</sub>)<sub>3</sub>In(SO<sub>4</sub>)<sub>3</sub> converts from rhombohedral to monoclinic as the temperature drops below 80&nbsp;°C, and converts back into a rhombohedral form with space group ''R''3''c'' as the temperature rises above 110&nbsp;°C.<ref name=Joli80/> The low temperature monoclinic form has space group ''P''2<sub>1</sub>/''c'', a=8.96, b=15.64 c=9.13 β=108.28° Z=4<ref name=Joli80/> The high temperature form is termed "β-". An explanation for this transition is that ammonium (and also thallium) is a non-spherical ion and thus has lower symmetry.  However, when it is heated enough, dynamical disorder causing random orientations makes the ions on average spherically symmetric. Alkali metal ions are spherical in shape at all temperatures and form rhombohedral structures.<ref name=Joli80/> Double sulfates of this form exist of indium with the alkali metals sodium, potassium, rubidium, and cesium.  These can be formed by heating a solid mixture of the individual sulfates to 350&nbsp;°C.<ref name=Perret74>{{cite journal|last1=Perret|first1=R|last2=Tudo|first2=J|last3=Jolibois|first3=B|last4=Couchot|first4=P|title=Préparation et caractérisation cristallographique de quelques sulfates doubles d'indium(III) et de thallium(III), MI3MIII (SO4)3 (MI = Na, K, Rb et Cs)|journal=Journal of the Less Common Metals|date=July 1974|volume=37|issue=1|pages=9–12|language=fr|doi=10.1016/0022-5088(74)90003-4}}</ref>

{|class="wikitable" style="text-align:right"
!name
!formula
!molecular weight
!a Å
!c Å
!α
!volume Å<sup>3</sup>
!density
|-
| trisodium indium trisulfate
| {{Chem2|Na3In(SO4)3}}
| 471.97
| 13.970
| 8.771
| 109°00′
| 494
| 3.172
|-
| tripotassium indium trisulfate
| {{Chem2|K3In(SO4)3}}
| 520.30
| 14.862
| 8.960
| 109°45′
| 571
| 3.026
|-
| trirubidium indium trisulfate
| {{Chem2|Rb3In(SO4)3}}
| 659.41
| 15.413
| 9.136
| 110°03′
| 626
| 3.498
|-
| tricesium indium trisulfate
| {{Chem2|Cs3In(SO4)3}}
| 801.72
| 16.068
| 9.211
| 110°36′
| 687
| 3.876
|-
| triammonium indium trisulfate
| {{Chem2|(NH4)3In(SO4)3}}
| 361.06
| 15.531
| 9.163
| 120°
| 1914.1
| 1.88
|-
| colspan="8" |
|-
| ammonium indium disulfate
| {{Chem2|NH4In(SO4)2}}
| 324.98
| 4.902
| 8.703
| 73.643
| 171.27
| 3.15
|-
| rubidium indium disulfate
| {{Chem2|RbIn(SO4)2}}
| 392.41
| 4.908
| 8.7862
| 73.781
| 173.50
| 3.75
|-
| cesium indium disulfate
| {{Chem2|CsIn(SO4)2}}
| 439.85
| 4.956
| 9.2567
| 74.473
| 187.26
| 3.90
|-
| thallium indium disulfate
| {{Chem2|TlIn(SO4)2}}
| 511.33
| 4.919
| 8.7882
| 73.748
| 174.27
| 4.87
|}
Another series of anhydrous rhombohedral double salts in the same series of TlFe(SO<sub>4</sub>)<sub>2</sub> exists.  These can be made by heating a mixture of anhydrous sulfates at 350&nbsp;°C, or by dehydrating hydrous double alum type salts at 300&nbsp;°C.  The substances in this series are RbIn(SO<sub>4</sub>)<sub>2</sub>, CsIn(SO<sub>4</sub>)<sub>2</sub>, TlIn(SO<sub>4</sub>)<sub>2</sub> and NH<sub>4</sub>In(SO<sub>4</sub>)<sub>2</sub>. Although KIn(SO<sub>4</sub>)<sub>2</sub> exists it has a different crystalline form.<ref name=Perr72>{{cite journal|last1=Perret|first1=R.|last2=Couchot|first2=P.|title=Preparation et caracterisation cristallographique des sulfates et seleniates doubles anhydres d'indium M<sup>1</sup>In(XO<sub>4</sub>)<sub>2</sub>|journal=Journal of the Less Common Metals|date=June 1972|volume=27|issue=3|pages=333–338|language=fr|doi=10.1016/0022-5088(72)90065-3}}</ref>

===Hydrated double sulfates===
Hydrated double salts of indium in an [[alum]] structure exist with formula M<sup>I</sup>In(SO<sub>4</sub>)<sub>2</sub>·12H<sub>2</sub>O. All alums have a cubic crystal structure with space group ''Pa''3.<ref name=Beat81/> The indium cesium alum CsIn(SO<sub>4</sub>)<sub>2</sub>•12H<sub>2</sub>O<ref name=Rud004>{{cite journal|last1=Rudolph|first1=Wolfram W.|last2=Fischer|first2=Dieter|last3=Tomney|first3=Madelaine R.|last4=Pye|first4=Cory C.|title=Indium(iii) hydration in aqueous solutions of perchlorate, nitrate and sulfate. Raman and infrared spectroscopic studies and ab-initio molecular orbital calculations of indium(iii)-water clusters|journal=Physical Chemistry Chemical Physics|date=2004|volume=6|issue=22|pages=5145|doi=10.1039/b407419j|url=https://www.researchgate.net/publication/250465251|access-date=31 May 2015|bibcode=2004PCCP....6.5145R}}</ref> has formula weight 656.0, unit cell width 12.54&nbsp;Å, cell volume 1972&nbsp;Å<sup>3</sup> and density 2.20&nbsp;g/cm<sup>3</sup>.<ref name=Beat81>{{cite journal|last1=Beattie|first1=James K.|last2=Best|first2=Stephen P.|last3=Skelton|first3=Brian W.|last4=White|first4=Allan H.|title=Structural studies on the caesium alums, CsM III [SO<sub>4</sub>]<sub>2</sub>•12H<sub>2</sub>O|journal=Journal of the Chemical Society, Dalton Transactions|date=1981|issue=10|pages=2105–2111|doi=10.1039/DT9810002105}}</ref> It has the β alum structure.<ref name=Arm97>{{cite journal|last1=Armstrong|first1=Robert S.|last2=Berry|first2=Andrew J.|last3=Cole|first3=Bradley D.|last4=Nugent|first4=Kerry W.|title=Chromium luminescence as a probe of site effects in the alum lattice|journal=Journal of the Chemical Society, Dalton Transactions|date=1997|issue=3|pages=363–366|doi=10.1039/A605705E}}</ref> The cesium alum can be used in the analysis of indium.  It precipitates when [[cesium nitrate]] is added to indium sulfate solution with extra sulfuric acid added.<ref>{{cite book|last1=Busev|first1=A.I.|title=The Analytical Chemistry of Indium|date=22 October 2013|publisher=Elsevier|page=5|url=https://books.google.com/books?id=pVf9BAAAQBAJ&pg=PA5|isbn=9781483149554}}</ref>

Indium ammonium alum NH<sub>4</sub>In(SO<sub>4</sub>)<sub>2</sub>·12H<sub>2</sub>O<ref name=Ekeley36>{{cite journal|last1=Ekeley|first1=John B.|last2=Potratz|first2=Herbert A.|title=Some Double Salts of Indium and Organic Bases|journal=Journal of the American Chemical Society|date=June 1936|volume=58|issue=6|pages=907–909|doi=10.1021/ja01297a016}}</ref> is fairly unstable at room temperature and must be crystallised below 5&nbsp;°C.<ref>{{cite journal|last1=Fimland|first1=B. O.|last2=Svare|first2=I|title=NMR and dielectric studies of NH4+ motion in some ammonium alums|journal=Physica Scripta|date=1 September 1987|volume=36|issue=3|pages=559–562|doi=10.1088/0031-8949/36/3/031|bibcode=1987PhyS...36..559F|s2cid=250876849 }}</ref> It decomposes at 36&nbsp;°C to a tetrahydrate.<ref>{{cite book|title=The Encyclopædia Britannica: A Dictionary of Arts, Sciences, and General Literature|date=1888|page=533|volume=5|url=https://books.google.com/books?id=HKgMAAAAYAAJ&pg=PA533|access-date=3 June 2015}}</ref> It changes to a [[ferroelectric]] phase below 127K.<ref name=Bailey73>{{cite journal|last1=Bailey|first1=W. C.|last2=Story|first2=H. S.|title=Nuclear quadrupole coupling of 115In in NH<sub>4</sub>In(SO<sub>4</sub>)<sub>2</sub>•12H<sub>2</sub>O|journal=The Journal of Chemical Physics|date=1973|volume=58|issue=3|pages=1255–1256|doi=10.1063/1.1679317|bibcode=1973JChPh..58.1255B}}</ref> The alum methyl ammonium indium sulfate dodecahydrate CH<sub>3</sub>NH<sub>3</sub>In(SO<sub>4</sub>)<sub>2</sub>·12H<sub>2</sub>O becomes ferroelectric below 164K.<ref name=Navalgund75>{{cite journal|last1=Navalgund|first1=R. R.|last2=Gupta|first2=L. C.|title=EPR of Cr3+ in Methyl Ammonium Indium Sulfate Dodecahydrate|journal=Physica Status Solidi B|date=1 September 1975|volume=71|issue=1|pages=K87–K90|doi=10.1002/pssb.2220710161|bibcode=1975PSSBR..71...87N}}</ref> Potassium indium alum has not been crystallised.<ref>{{cite journal|last1=Purkayastha|first1=B.C.|last2=Das|first2=H.B.|title=A STUDY ON THE PROBABLE EXISTENCE OF POTASSIUM INDIUM ALUM WITH RADIOACTIVE NUCLEI. PART I|journal=Journal of the Indian Chemical Society|date=1 February 1963|volume=40}}</ref> Rubidum indium alum is highly [[efflorescent]] very easily losing its water.<ref>{{cite journal|last1=Ivanovski|first1=Vladimir|last2=Petruševski|first2=Vladimir M.|last3=Šoptrajanov|first3=Bojan|title=Vibrational spectra of hexaaqua complexes.|journal=Vibrational Spectroscopy|date=April 1999|volume=19|issue=2|pages=425–429|doi=10.1016/S0924-2031(98)00068-X}}</ref>

Another series of monoclinic hydrated double salts have four water molecules MIn(SO<sub>4</sub>)<sub>2</sub>·4H<sub>2</sub>O, with five formulae per unit cell, where M is NH<sub>4</sub>, K or Rb and the point group is P2<sub>1</sub>/c.  The prototype substance for the series is (NH<sub>4</sub>)Sm(SO<sub>4</sub>)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>.

{|class="wikitable" style="text-align:right"
!formula
!weight
!a Å
!b Å
!c Å
!β
!volume Å<sup>3</sup>
!density
!ref
|-
| NH<sub>4</sub>In(SO<sub>4</sub>)<sub>2</sub>•4H<sub>2</sub>O
| 397.04
| 10.651
| 10.745
| 9.279
| 102.67°
| 1036.08
| 3.182
|<ref>{{cite web|title=inorganic Materials Database|url=http://crystdb.nims.go.jp/crystdb/search-details?pageS=1&search-type=search-materials&pageP=0&need_more_type=prototype_number&tab=pageA&isConditionValueError=false&page=1&tabDetail=pageS&pageSubP=1&reference_id=4294985445&pageSubD=1&tabSub=pageA&pageSubA=1&isVisiblePeriodicTable=true&isNeedMoreValueError=false&need_more_value=&substance_id=17764&material_id=4295275489&condition_value=In+S+O+H+N&pageSubS=1&history=true&pageD=0&pageA=1&condition_type=chemical_system&errorCode=0|website=Atom Work|access-date=31 May 2015|archive-date=4 March 2016|archive-url=https://web.archive.org/web/20160304085836/http://crystdb.nims.go.jp/crystdb/search-details?pageS=1&search-type=search-materials&pageP=0&need_more_type=prototype_number&tab=pageA&isConditionValueError=false&page=1&tabDetail=pageS&pageSubP=1&reference_id=4294985445&pageSubD=1&tabSub=pageA&pageSubA=1&isVisiblePeriodicTable=true&isNeedMoreValueError=false&need_more_value=&substance_id=17764&material_id=4295275489&condition_value=In+S+O+H+N&pageSubS=1&history=true&pageD=0&pageA=1&condition_type=chemical_system&errorCode=0|url-status=dead}}</ref>
|-
| KIn(SO<sub>4</sub>)<sub>2</sub>•4H<sub>2</sub>O
| 418.10
| 10.581
| 10.641
| 9.224
| 101.93°
| 1016.1
| 3.416
|<ref>{{cite web|title=Inorganic Materials Database|url=http://crystdb.nims.go.jp/crystdb/search-details?pageS=1&search-type=search-materials&pageP=0&need_more_type=prototype_number&tab=pageA&isConditionValueError=false&page=1&tabDetail=pageS&pageSubP=1&reference_id=4294985445&pageSubD=1&tabSub=pageA&pageSubA=1&isVisiblePeriodicTable=true&isNeedMoreValueError=false&need_more_value=&substance_id=17760&material_id=4295275485&condition_value=In+S+O+H+K&pageSubS=1&history=true&pageD=0&pageA=1&condition_type=chemical_system&errorCode=0|website=AtomWork|access-date=31 May 2015}}{{Dead link|date=May 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
|-
| RbIn(SO<sub>4</sub>)<sub>2</sub>•4H<sub>2</sub>O
| 464.47
| 10.651
| 10.745
| 9.279
| 102.67°
| 1036.1
| 3.722
|<ref>{{cite web|title=Inorganic Materials Database|url=http://crystdb.nims.go.jp/crystdb/search-details?pageS=1&search-type=search-materials&pageP=0&need_more_type=prototype_number&tab=pageA&isConditionValueError=false&page=1&tabDetail=pageS&pageSubP=1&reference_id=4294985445&pageSubD=1&tabSub=pageA&pageSubA=1&isVisiblePeriodicTable=true&isNeedMoreValueError=false&need_more_value=&substance_id=17762&material_id=4295275487&condition_value=In+S+O+H+Rb&pageSubS=1&history=true&pageD=0&pageA=1&condition_type=chemical_system&errorCode=0|website=AtomWork|access-date=31 May 2015}}{{Dead link|date=May 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
|-
|}

[[Cadmium]] can also form a double sulfate, Cd<sub>3</sub>In<sub>2</sub>(SO<sub>4</sub>)<sub>6</sub>·26H<sub>2</sub>O.<ref name=Fed83>{{cite journal|last1=Fedorov|first1=P.I.|last2=Lovetskaya|first2=G.A.|last3=Starikova|first3=Z.A.|last4=Vlaskin|first4=O.I.|journal=Zhurnal Neorganicheskoj Khimii|date=November 1983|volume=28|issue=11|pages=2962–2965|title=[Study of zinc- and cadmium sulfates interaction with indium sulfate in aqueous solution at 25 deg C]}}</ref>

Crystals with less water also exist like KIn(SO<sub>4</sub>)<sub>2</sub>·H<sub>2</sub>O.<ref>{{cite journal|last1=Mukhatarova|bibcode=1979SPhD...24..140M|first1=N. N.|last2=Rastsvetaeva|first2=R. K.|last3=Ilyukhin|first3=V. V.|last4=Belov|first4=N. V.|title=Crystal structure of KIn(SO4)<sub>2</sub>·H<sub>2</sub>O|journal=Soviet Physics Doklady|date=March 1979|volume=24|page=140}}</ref>

===Organic double sulfates===
Organic base double sulfates of indium include the [[guanidinium]] salt [C(NH<sub>2</sub>)<sub>3</sub>][In(H<sub>2</sub>O)<sub>2</sub>(SO<sub>4</sub>)<sub>2</sub>], which crystallises in a monoclinic system with space group ''P''2<sub>1</sub>/''c'' a = 4.769&nbsp;Å, b = 20.416&nbsp;Å, c = 10.445&nbsp;Å, β = 93.39°, cell volume 1015.3&nbsp;Å<sup>3</sup>, 4 formulas per cell and density 2.637. [H<sub>2</sub>(4,4'-bi-py)][In<sub>2</sub>(H<sub>2</sub>O)<sub>6</sub>(SO<sub>4</sub>)<sub>4</sub>]·2H<sub>2</sub>O crystallises in the [[triclinic]] system with a = 7.143&nbsp;Å, b = 7.798&nbsp;Å, c = 12.580&nbsp;Å, α = 107.61°, β = 98.79°, γ = 93.89°, cell volume 655.2 Å<sup>3</sup>, one formula per cell and density 2.322.<ref name=Petrosyants006>{{cite journal|last1=Petrosyants|first1=S. P.|last2=Ilyukhin|first2=A. B.|last3=Ketsko|first3=V. A.|title=Supramolecular compounds of indium sulfates with nitrogen-containing cations|journal=Russian Journal of Coordination Chemistry|date=November 2006|volume=32|issue=11|pages=777–783|doi=10.1134/s1070328406110029|s2cid=95016069}}</ref> [H(2,2'-bipy)][In(H<sub>2</sub>O)(SO<sub>4</sub>)<sub>2</sub>]·2H<sub>2</sub>O, the [[hexamethylenediamine]] salt [H<sub>3</sub>N(CH<sub>2</sub>)<sub>6</sub>NH<sub>3</sub>][In(H<sub>2</sub>O)<sub>2</sub>(SO<sub>4</sub>)<sub>2</sub>]<sub>2</sub>·2H<sub>2</sub>O and [H<sub>2</sub>(Py(CH<sub>2</sub>)<sub>3</sub>Py)][In(H<sub>2</sub>O)<sub>2</sub>(SO<sub>4</sub>)<sub>2</sub>]<sub>2</sub>·2H<sub>2</sub>O also exist.<ref name="Petrosyants006" /> Yet other organic derivatives include those of [[triethylenetetramine]],<ref>{{cite journal|last1=Tian|first1=Zhen-Fen|title=Solvothermal Synthesis and Characterization of One-dimensional Chained Indium-Sulfate|journal=Chemical Journal of Chinese Universities|date=March 2009}}</ref> and [[amylamine|amylammonium]].<ref name="Ekeley36"/> Tri-''μ''-sulfato-''κ''<sup>6</sup>O:O'-bis[aqua(1,10-phenanthroline-''κ''<sup>2</sup>N,N')indium(III)] dihydrate, [In<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>(C<sub>12</sub>H<sub>8</sub>N<sub>2</sub>)2(H<sub>2</sub>O)<sub>2</sub>]·2H<sub>2</sub>O, has a 1,10-phenanthroline molecule linked to each indium ion.  Two indium ions are linked via three sulfate groups. It forms triclinic crystals with two formulas per unit cell. The density is 2.097 g/cm<sup>3</sup>.<ref>{{cite journal|last1=Shen|first1=Fwu Ming|last2=Lush|first2=Shie Fu|title=Tri-µ-sulfato-κ6O:O'-bis[aqua(1,10-phenanthroline- κ2N,N')indium(III)] dihydrate|journal=Acta Crystallographica Section E|date=15 September 2010|volume=66|issue=10|pages=m1260–m1261|doi=10.1107/S1600536810036330|pmid=21587408|url=http://journals.iucr.org/e/issues/2010/10/00/xu5026/xu5026sup0.html|access-date=3 June 2015|pmc=2983182}}</ref>

Dimethylindium sulfate [(CH<sub>3</sub>)<sub>2</sub>In]<sub>2</sub>SO<sub>4</sub> can be made by reacting [[trimethylindium]] with dry sulfuric acid.<ref name=Olapinski73>{{cite journal|last1=Olapinski|first1=H.|last2=Weidlein|first2=J.|title=Bis(dialkylmetall)sulfate der elemente gallium, indium und thallium|journal=Journal of Organometallic Chemistry|date=June 1973|volume=54|pages=87–93|doi=10.1016/s0022-328x(00)84995-5}}</ref>

===Mixed===
A double indium sulfate chloride salt has formula In<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>·InCl<sub>3</sub>·(17±1)H<sub>2</sub>O.<ref name=Kartz77>{{cite journal|last1=Kartzmark|first1=Elinor M.|title=Double salts of indium trichloride with the alkali chlorides, with ammonium chloride, and with indium sulfate|journal=Canadian Journal of Chemistry|date=August 1977|volume=55|issue=15|pages=2792–2798|doi=10.1139/v77-388|doi-access=}}</ref>

===Monovalent===
Indium(I) sulfate, In<sub>2</sub>SO<sub>4</sub> can be made in a solid state by heating indium metal with indium(III) sulfate,<ref>{{cite journal|last1=Dmitriev|first1=V.S.|last2=Malinov|first2=S.A.|last3=Dubovitskaya|first3=L.G.|last4=Smirnov|first4=V.A.|title=Vzaimodejstvie metallicheskogo indiya s sul'fatom indiya(3)|journal=Zhurnal Neorganicheskoj Khimii|date=September 1986|volume=31|issue=9|pages=2372–2377|trans-title=Metallic indium interaction with indium(3) sulfate|language=ru|issn=0044-457X}}</ref> but when dissolving in water or sulfuric acid, In<sup>+</sup> reacts to produce hydrogen gas.<ref name=Kozin>{{cite journal|last1=Kozin|first1=L.F.|last2=Egorova|first2=A.G.|title=Sul'fat odnovalentnogo indiya, ego sintez i svojstva|journal=Zhurnal Obshchej Khimii|date=May 1982|volume=52|issue=5|pages=1020–1024|trans-title=Monovalent indium sulfate, its synthesis and properties|language=ru|issn=0044-460X}}</ref> The mixed valence salt In<sup>I</sup>In<sup>III</sup>(SO<sub>4</sub>)<sub>2</sub> is also made by heating indium metal with indium(III) sulfate.<ref>{{cite book|last1=Downs|first1=A. J.|title=Chemistry of Aluminium, Gallium, Indium, and Thallium|date=31 May 1993|publisher=Springer|page=211|url=https://books.google.com/books?id=v-04Kn758yIC&pg=PA211|isbn=9780751401035}}</ref>

==Use==
[[File:Philco Surface Barrier transistor=1953.jpg|thumb|Philco surface-barrier transistor developed and produced in 1953]]
Indium sulfate is a commercially available chemical.  It can be used to electroplate indium metal,<ref>{{cite book|last1=Schwarz-Schampera|first1=Ulrich|last2=Herzig|first2=Peter M.|title=Indium: Geology, Mineralogy, and Economics|date=14 March 2013|publisher=Springer Science & Business Media|page=171|url=https://books.google.com/books?id=Fl4yBwAAQBAJ&pg=PA171|isbn=9783662050767}}</ref> as a hardening agent in gold electroplating<ref>{{cite web|title=Indium Corp. In2(SO4)3 Indium Sulfate Anhydrous|url=http://www.matweb.com/search/datasheettext.aspx?matguid=8e49d730509840efad0569f34042ca39|access-date=2 June 2015}}</ref> or to prepare other indium containing substances such as [[copper indium selenide]]. It has been sold as a health supplement, even though there is no evidence of benefit to humans, and it is toxic.<ref>{{cite web|last1=Bradley|first1=David|title=Health Benefits of Indium|url=http://www.sciencebase.com/science-blog/spurious-health-benefits-of-indium.html|access-date=2 June 2015|date=2 July 2008|archive-url=https://web.archive.org/web/20060316122701/http://www.sciencebase.com/science-blog/spurious-health-benefits-of-indium.html|archive-date=16 March 2006|url-status=dead}}</ref>

The first high-frequency [[transistor]] was the [[surface-barrier transistor|surface-barrier germanium transistor]] developed by [[Philco]] in 1953, capable of operating up to 60&nbsp;MHz.<ref>{{cite journal|journal=Proceedings of the IRE|date=December 1953|first1=W.E.|last1=Bradley|title=The Surface-Barrier Transistor: Part I-Principles of the Surface-Barrier Transistor|volume=41|issue=12|pages=1702–1706|doi=10.1109/JRPROC.1953.274351|s2cid=51652314}}</ref> These were made by etching depressions into an N-type germanium base from both sides with jets of indium sulfate until it was a few ten-thousandths of an inch thick. [[Indium]] electroplated into the depressions formed the collector and emitter.<ref>{{cite news|journal=Wall Street Journal|date=4 December 1953|page=4|title=Philco Claims Its Transistor Outperforms Others Now In Use}}</ref><ref>{{cite journal|journal=Electronics Magazine|date=January 1954|title=Electroplated Transistors Announced}}</ref>

==References==
{{reflist}}

{{Indium compounds}}
{{Sulfates}}
{{Use dmy dates|date=April 2017}}

[[Category:Sulfates]]
[[Category:Indium compounds]]