Strontium sulfate

Strontium sulfate (SrSO₄) is the sulfate salt of strontium. It is a white crystalline powder and occurs in nature as the mineral celestine. It is poorly soluble in water to the extent of 1 part in 8,800. It is more soluble in dilute HCl and nitric acid and appreciably soluble in alkali chloride solutions (e.g. sodium chloride).

Strontium sulfate^[1]

Names
IUPAC name Strontium sulfate
Other names Celestine
Identifiers
CAS Number	7759-02-6 Y
3D model (JSmol)	Interactive image
ChemSpider	2341151 Y
ECHA InfoCard	100.028.955
EC Number	231-850-2
PubChem CID	3084026
UNII	7Q3KX2L47F N
CompTox Dashboard (EPA)	DTXSID10884419
InChI InChI=1S/H2O4S.Sr/c1-5(2,3)4;/h(H2,1,2,3,4);/q;+2/p-2 Y Key: UBXAKNTVXQMEAG-UHFFFAOYSA-L Y InChI=1/H2O4S.Sr/c1-5(2,3)4;/h(H2,1,2,3,4);/q;+2/p-2 Key: UBXAKNTVXQMEAG-NUQVWONBAV
SMILES [Sr+2].[O-]S([O-])(=O)=O
Properties
Chemical formula	SrSO4
Molar mass	183.68 g/mol
Appearance	white orthorhombic crystals
Density	3.96 g/cm3
Melting point	1,606 °C (2,923 °F; 1,879 K)
Solubility in water	0.0135 g/100 mL (25 °C) 0.014 g/100 mL (30 °C)
Solubility product (Ksp)	3.44 x 10−7
Solubility	insoluble in ethanol, alkalis slightly soluble in acids
Magnetic susceptibility (χ)	−57.9·10−6 cm3/mol
Refractive index (nD)	1.622[2]
Structure
Crystal structure	Orthorhombic, oP24
Space group	Pnma, No. 62[3]
Thermochemistry
Std molar entropy (S⦵298)	117.0 J·mol−1·K−1
Std enthalpy of formation (ΔfH⦵298)	−1453.1 kJ·mol−1
Hazards
NFPA 704 (fire diamond)	1 0 0
Flash point	Not flammable
Safety data sheet (SDS)	External MSDS data
Related compounds
Other anions	Strontium chloride Strontium oxide
Other cations	Beryllium sulfate Magnesium sulfate Calcium sulfate Barium sulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Structure

Strontium sulfate is a polymeric material, isostructural with barium sulfate. Crystallized strontium sulfate is utilized by a small group of radiolarian protozoa, called the Acantharea, as a main constituent of their skeleton.

Applications and chemistry

Strontium sulfate is of interest as a naturally occurring precursor to other strontium compounds, which are more useful. In industry it is converted to the carbonate for use as ceramic precursor and the nitrate for use in pyrotechnics.^[4]

The low aqueous solubility of strontium sulfate can lead to scale formation in processes where these ions meet. For example, it can form on surfaces of equipment in underground oil wells depending on the groundwater conditions.^[5][6]