Birnessite
(Na,Ca,K)0.6(Mn4+,Mn3+)2O4·1.5H2OIMA symbol: Birgrandfathered
Birnessite is an oxide or hydroxide mineral with the formula (Na,Ca,K)0.6(Mn4+,Mn3+)2O4·1.5H2O. It has a calculated density of 3.297 g/cm3.
Crystallography
| Space group | C -1 |
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| Cell (Å, °) | a = 5.178, b = 2.8509, c = 7.3344; α = 89.45, β = 103.18, γ = 89.91 |
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| Cell volume | 105.412 ų, Z = 2 |
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| Axial ratios | 1.8163:1:2.5727calculated from COD 9010155 |
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| Source structure | COD 9010155 (American Mineralogist, 2007) — 1 of 9 structures |
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Powder X-ray diffraction (calculated)
| d (Å) | 7.141 | 3.57 | 2.521 | 2.427 | 1.868 | 2.147 |
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| I/I₀ | 100 | 26.6 | 9.7 | 8.2 | 7.7 | 6.9 |
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xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9010155; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.297 g/cm³calculated from COD 9010155 |
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Classification
| Nickel-Strunz (10th) | 4.FL.45Wikidata (CC0) |
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| Nickel-Strunz (9th) | 4.FL.45Wikidata (CC0) |
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