Kröhnkite
Na2Cu(SO4)2·2H2OIMA symbol: Khkgrandfathered
Kröhnkite is a sulfate mineral with the formula Na2Cu(SO4)2·2H2O, crystallizing in the monoclinic system. It has a Mohs hardness of 2-5, typically blue in color, with a vitreous luster, a specific gravity of 23. Its streak is white.
Photos
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Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | P 1 21/c 1 |
| Cell (Å, °) | a = 5.807, b = 12.656, c = 5.517; α = 90, β = 108.32, γ = 90 |
| Cell volume | 384.912 ų, Z = 2 |
| Axial ratios | 0.4588:1:0.4359calculated from COD 9007608 |
| Source structure | COD 9007608 (Acta Crystallographica, Section B, 1975) — 1 of 2 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.285 | 2.935 | 6.328 | 2.765 | 3.712 | 4.157 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 98.9 | 96 | 92.7 | 65.5 | 51.8 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9007608; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 2.914 g/cm³calculated from COD 9007608 |
|---|---|
| Hardness (Mohs) | 2-5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 23 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Color | bluesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) |
| Luster | vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 337.68 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Na 13.62%, Cu 18.82%, S 18.99%, O 47.38%, H 1.19% |
Classification
| Nickel-Strunz (10th) | 7.CC.30Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 7.CC.30Wikidata (CC0) |