Sulfate carbonate

The sulfate carbonates are a compound carbonates, or mixed anion compounds that contain sulfate and carbonate ions. Sulfate carbonate minerals are in the 7.DG and 5.BF Nickel-Strunz groupings.^[1]

They may be formed by crystallization from a water solution, or by melting a carbonate and sulfate together.

In some structures carbonate and sulfate can substitute for each other. For example a range from 1.4 to 2.2 Na₂SO₄•Na₂CO₃ is stable as a solid solution.^[2] Silvialite can substitute about half its sulfate with carbonate^[3] and the high temperature hexagonal form of sodium sulfate (I) Na₂SO₄ can substitute unlimited proportions of carbonate instead of sulfate.^[4]

^ "Susannite: Mineral information, data and localities". www.mindat.org. Retrieved 10 May 2020.
^ Green, Stanley J.; Frattali, Francis J. (September 1946). "The System Sodium Carbonate-Sodium Sulfate-Sodium Hydroxide-Water at 100°". Journal of the American Chemical Society. 68 (9): 1789–1794. doi:10.1021/ja01213a033.
^ Teertstra, D. K.; Schindler, M.; Sherriff, B. L.; Hawthorne, F. C. (June 1999). "Silvialite, a new sulfate-dominant member of the scapolite group with an Al-Si composition near the 14/ m – P 4 2 / n phase transition". Mineralogical Magazine. 63 (3): 321–329. Bibcode:1999MinM...63..321T. doi:10.1180/002646199548547. ISSN 0026-461X. S2CID 129588463.
^ Eysel, W.; Höfer, H. H.; Keester, K. L.; Hahn, Th. (1985-02-01). "Crystal chemistry and structure of Na 2 SO 4 (I) and its solid solutions". Acta Crystallographica Section B: Structural Science. 41 (1): 5–11. Bibcode:1985AcCrB..41....5E. doi:10.1107/S0108768185001501. ISSN 0108-7681.

[sus-1] "Susannite: Mineral information, data and localities". www.mindat.org. Retrieved 10 May 2020.

[2] Green, Stanley J.; Frattali, Francis J. (September 1946). "The System Sodium Carbonate-Sodium Sulfate-Sodium Hydroxide-Water at 100°". Journal of the American Chemical Society. 68 (9): 1789–1794. doi:10.1021/ja01213a033.

[3] Teertstra, D. K.; Schindler, M.; Sherriff, B. L.; Hawthorne, F. C. (June 1999). "Silvialite, a new sulfate-dominant member of the scapolite group with an Al-Si composition near the 14/ m – P 4 2 / n phase transition". Mineralogical Magazine. 63 (3): 321–329. Bibcode:1999MinM...63..321T. doi:10.1180/002646199548547. ISSN 0026-461X. S2CID 129588463.

[4] Eysel, W.; Höfer, H. H.; Keester, K. L.; Hahn, Th. (1985-02-01). "Crystal chemistry and structure of Na 2 SO 4 (I) and its solid solutions". Acta Crystallographica Section B: Structural Science. 41 (1): 5–11. Bibcode:1985AcCrB..41....5E. doi:10.1107/S0108768185001501. ISSN 0108-7681.

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