Erbium(III) sulfate

Erbium(III) sulfate
Names
	IUPAC name Erbium(III) sulfate
	Other names Dierbium trisulphate; Erbium Sulfate;
Identifiers
CAS Number	13478-49-4 Anhydrous; 10031-52-4 Octahydrate;
3D model (JSmol)	Interactive image;
ChemSpider	145961;
ECHA InfoCard	100.033.421
EC Number	680-959-5;
PubChem CID	166829;
UNII	859WC72L9X;
CompTox Dashboard (EPA)	DTXSID40648465;
	InChI InChI=1S/2Er.3H2O4S/c;;31-5(2,3)4/h;;3(H2,1,2,3,4)/q2*+3;;;/p-6 Key: SYDXSHCNMKOQFW-UHFFFAOYSA-H;
	SMILES [O-]S(=O)(=O)[O-].[O-]S(=O)(=O)[O-].[O-]S(=O)(=O)[O-].[Er+3].[Er+3];
Properties
Chemical formula	Er2O12S3
Molar mass	622.69 g·mol−1
Appearance	pink crystalline solid
Density	3.678 g/cm3 (anhydrous) ; 3.217 g/cm3 (octahydrate)
Melting point	400 °C (752 °F; 673 K) decomposes (octahydrate)
Solubility in water	octahydrate ; 160 g/L (20 °C) ; 65.3 g/L (40 °C)
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P264+P265, P271, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Erbium(III) sulfate is an erbium compound with the chemical formula Er₂(SO₄)₃. It is a pink crystalline salt, readily absorbing water to form an octahydrate.^[1] It is used as a colorant in glass manufacturing and porcelain enamel glazes, as well as a dopant in the production of optical fiber.^[2]

Structure

The anhydrous compound (Er₂(SO₄)₄) forms orthorhombic crystals (space group: Pbcn (No. 60), a = 1269.5 pm, b = 915.0 pm, c = 923.7 pm, molar volume = 161.5 cm³/mol, formula units = 4 units per cell).^[3]

A dimorphic hydrogensulfate (Er(HSO₄)₃) exists:

Form I: orthorhombic (space group: Pbca (No. 61), a = 1195.0 pm, b = 949.30 pm, c = 1644.3 pm, molar volume = 140.4 cm³/mol, formula units = 8 units per cell)^[3]
Form II: monoclinic (space group: P2₁/n (No. 14), a = 520.00 pm, b = 1357.8 pm, c = 1233.4 pm, β = 92.13 °, molar volume = 131.0 cm³/mol, formula units = 4 units per cell)^[3]

A mixed sulfate-hydrogensulfate (Er(HSO₄)(SO₄)) forms monoclinic crystals (space group: P2₁/n (No. 14), a = 545.61 pm, b = 1075.6 pm, c = 1053.1 pm, β = 104.58 °, molar volume = 90.0 cm³/mol, formula units = 4 units per cell).^[3]

Synthesis

Erbium sulfate can be prepared by dissolving erbium(III) oxide in sulfuric acid:^[4]

Er₂O₃ + 3 H₂SO₄ → Er₂(SO₄)₃ + 3 H₂O

The rod shaped "Form I" of the hydrogensulfate crystallizes from concentrated sulfuric acid at 250 °C.^[3] In diluted sulfuric acid (85% with added Na₂SO₄), the brick shaped "Form II" crystallizes at 250 °C, while at 60 °C the mixed sulfate-hydrogensulfate is obtained.

The anhydrous compound cannot be prepared from solution but crystallizes from molten salt (with sodium impurities).^[3]

References

^ Perry, Dale L. (2016-04-19). Handbook of Inorganic Compounds. CRC Press. pp. 164–165. ISBN 978-1-4398-1462-8.
^ "Erbium(III) sulfate octahydrate, 99.9% (REO) 10 g | Buy Online | Thermo Scientific Chemicals". www.thermofisher.com. Retrieved 2025-08-12.
^ ^a ^b ^c ^d ^e ^f Wickleder, Mathias S. (1998). "Sulfate und Hydrogensulfate des Erbiums: Er(HSO4)3-I, Er(HSO4)3-II, Er(SO4)(HSO4) und Er2(SO4)3". Zeitschrift für anorganische und allgemeine Chemie (in German). 624 (8): 1347–1354. doi:10.1002/(SICI)1521-3749(199808)624:8<1347::AID-ZAAC1347>3.0.CO;2-W. ISSN 1521-3749.
^ Wickleder, Mathias S. (1998-10-01). "Synthesis, Crystal Structure, and Thermal Behavior of the Rare Earth Sulfates (H₅O₂)M(SO₄)₂ (M = Ho, Er, Y)". Chemistry of Materials. 10 (10): 3212–3216. doi:10.1021/cm980301w. ISSN 0897-4756.

[1] Perry, Dale L. (2016-04-19). Handbook of Inorganic Compounds. CRC Press. pp. 164–165. ISBN 978-1-4398-1462-8.

[2] "Erbium(III) sulfate octahydrate, 99.9% (REO) 10 g | Buy Online | Thermo Scientific Chemicals". www.thermofisher.com. Retrieved 2025-08-12.

[Wickleder-3] ^ ^a ^b ^c ^d ^e ^f Wickleder, Mathias S. (1998). "Sulfate und Hydrogensulfate des Erbiums: Er(HSO4)3-I, Er(HSO4)3-II, Er(SO4)(HSO4) und Er2(SO4)3". Zeitschrift für anorganische und allgemeine Chemie (in German). 624 (8): 1347–1354. doi:10.1002/(SICI)1521-3749(199808)624:8<1347::AID-ZAAC1347>3.0.CO;2-W. ISSN 1521-3749.

[4] Wickleder, Mathias S. (1998-10-01). "Synthesis, Crystal Structure, and Thermal Behavior of the Rare Earth Sulfates (H₅O₂)M(SO₄)₂ (M = Ho, Er, Y)". Chemistry of Materials. 10 (10): 3212–3216. doi:10.1021/cm980301w. ISSN 0897-4756.

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