Table 1. Solubility Data of Calcium Sulfates in H₂SO₄ Solutions from the Literature.

T, K	H2SO4, molality	pointsa	reported experimental error (%)	solid phase	reference
298.15–363.15	0–4.0030	20 (20)	0.1–2	CaSO4·2H2O	Wang et al.11
298.15–363.15	0.4854–0.4990	4 (4)	5	CaSO4·2H2O	Azimi and Papangelakis14
303.15–353.15	0–0.7931	12 (12)	6	CaSO4·2H2O	Farrah et al.15
298.15–333.15	0–4.7000	74 (76)b	4	CaSO4·2H2O	Marshall and Jones18
283.15–368.15	0–6.8429	31(44)c		CaSO4·2H2O	Zdanovskii et al.16,17
298.15–316.15	0–3.4081	2 (26)d	0.1	CaSO4·2H2O	Cameron and Breazeale19
298.15–363.15	0–4.6531	23 (28)e	0.1–2	CaSO4	Wang et al.11
363.15–378.15	0–0.7922	0 (8)	6	CaSO4	Farrah et al.15
398.15–623.15	0–1.2090	17(145)f	4	CaSO4	Marshall and Jones18
283.15–323.15	0–4.3767	24 (26)g		CaSO4	Zdanovskii16
373.15	2.64–7.90	0 (3)	0.45–4.117	CaSO4	Ling and Demopoulos13
398.15	0–1.0450	12 (12)	4	CaSO4·0.5H2O	Marshall and Jones18
298.15–368.15	0–6.8246	27 (32)h		CaSO4·0.5H2O	Zdanovskii et al.17
373.15	0–1.93	14 (14)	1.70–7.52	CaSO4·0.5H2O	Ling and Demopoulos13

^aTotal number of data points in the parentheses.

^bExcept points 2.384 and 4.7 mol/kg H₂SO₄ at 313.15 K.

^cAll points at 283.15 excluded except at 2.5525 mol/kg H₂SO₄, excluded points from 1.8038 to 6.8011 mol/kg H₂SO₄ at 298.15 K, excluded 0.8296 mol/kg H₂SO₄ at 308.15 K, all points excluded at 315.15 K, excluded 4.3781 and 6.8047 mol/kg H₂SO₄ at 323.15 K, excluded 6.8146 mol/kg H₂SO₄ at 348.15 K and 6.8429 mol/kg H₂SO₄ at 368.15 K.

^dIncluded only 0.0831 mol/kg H₂SO₄ at 298.15 K and 0.0496 mol/kg H₂SO₄ at 316.15 K.

^eExcept points 3.0 and 4.5007 mol/kg H₂SO₄ at 323.15 K, 0.2001 and 3.0021 mol/kg H₂SO₄ at 348.15 K, and 3.0002 mol/kg H₂SO₄ at 363.15 K.

^fAll points included at 398.15 K, included only 0.476–0.564 mol/kg H₂SO₄ at 423.15 K, included 0.00085–0.0023 and 0.481–0.578 mol/kg H₂SO₄ at 448.15 K, included 0.00014 and from 0.488 to 0.585 mol/kg H₂SO₄ at 473.15 K, all data above 473.15 K excluded.

^gIncluded all points except 2.5565 and 4.3767 mol/kg H₂SO₄ at 323.15 K.

^hIncluded all except points 6.8036 mol/kg H₂SO₄ at 298.15 K, 4.3823 and 6.8053 mol/kg H₂SO₄ at 323.15 K, 6.8121 mol/kg H₂SO₄ at 348.15 K, and 6.8246 mol/kg H₂SO₄ at 368.15 K.