Sulfate

Author: Hans-Jürgen Schwarz

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Overview

In this overview the most frequently occurring salts with suklphate as the anion are listed. The various salt phases are discussed in detail on separate pages, their occurrence and their damage potential is explained and the damage szmptoms are illustrated in an documentation..

Name	Formula	Solubility[g/l] 20°C	Deliqueszenz-humidity	Light refraction/ Birefringence	notes
Calciumsulfate - Gipsum	CaSO4•2H2O	2,41		nx = 1,521 ny = 1,523 nz = 1,530 Δ = 0,009	poorly water-soluble
Bassanite	CaSO4•0,5H2O	3,0		no = 1,558 ne = 1,586 Δ = 0,028	poorly water-soluble
Magnesiumsulfate - Epsomite	MgSO4•7H2O	710	90,1(20), 94(30)	nx = 1,433 ny = 1,455 nz = 1,461 Δ = 0,028	to prepare in aqueous solution at 50°C
Hexahydrite	MgSO4•6H2O	660		nx = 1,426 ny = 1,453 nz = 1,456 Δ = 0,030	to prepare in aqueous solution at 48 ° -69 ° C
Pentahydrite	MgSO4•5H2O			nx = 1,482 ny = 1,492 nz = 1,493 Δ = 0,011	not stable in air
Starkeyite	MgSO4•4H2O			nx = 1,49 ny = 1,491 nz = 1,497 Δ = 0,007	not stable in air
Kieserite	MgSO4•H2O	684(100°C)		nx = 1,523-1,520 ny = 1,535-1,533 nz = 1,586-1,584 Δ = 0,063-0,064	to produce in aqueous solution above 67 ° C
Darapskite	Na3(SO4)(NO3)• H2O			nx = 1,391 ny = 1,481 nz = 1,486 Δ = 0,095	produce from an aqueous solution of Na2SO4 andNaNO3 at 14°-50°C
Mirabilite	Na2SO4•10H2O	900	87(25), 90(23), 93,6(20)	nx = 1,394-1,396 ny = 1,396-1,410 nz = 1,398-1,419 Δ = 0,004-0,023	easily lose a little water and transforms at 32 ° C into thenardite which shows anomalous blue or brown interference colors
Natriumsulfate - Thenardite	Na2SO4	162	81,7 (25)	nx = 1,468 ny = 1,473 nz = 1,483 Δ = 0,015
Aphthitalite (Glaserite)	K3Na(SO4)2			no = 1,487-1,491 ne = 1,492-1,499 Δ = 0,005-0,008
Arcanite	K2SO4	110 147 (40)	97,6 (20)	nx = 1,494 ny = 1,495 nz = 1,497 Δ = 0,003
Astrakanite (Bloedite)	Na2Mg(SO4)2•4H2O			nx = 1,483-1,486 ny = 1,486-1,488 nz = 1,487-1,489 Δ = 0,004-0,003
Schönite (Pikromerite)	K2Mg(SO4)2•6H2O	250		nx = 1,461 ny = 1,463 nz = 1,476 Δ = 0,015
Boussingaultite	(NH4)2Mg(SO4)2•6H2O	159 (0) 1300 (100)		nx = 1,472 ny = 1,473 nz = 1,479 Δ = 0,007
Syngenite	K2Ca(SO4)2•H2O	2,5		nx = 1,501 ny = 1,517 nz = 1,518 Δ = 0,017
Gorgeyite	K2Ca5(SO4)6•H2O			nx = 1,560 ny = 1,569 nz = 1,584 Δ = 0,024
Ettringite	Ca6Al2(SO4)3(OH)12• 26H2O			no = 1,491 ne = 1,470 Δ = 0,021	not water-soluble
Thaumasite	Ca3Si(OH)6(CO3)(SO4)• 12H2O			no =1,468 ne = 1,507 Δ = 0,039	not water-soluble

an atom or molecule with a negative electrical charge.