Borax
Na2B4O5(OH)4·8H2OIMA symbol: Brxgrandfathered
Borax is a borate mineral with the formula Na2B4O5(OH)4·8H2O. It has a Mohs hardness of 2-2.5, typically white, gray or green in color, with an earthy or resinous luster, a specific gravity of 1.69-1.72. Its streak is white.
Photos
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Crystallography
| Space group | C 1 2/c 1 |
|---|---|
| Cell (Å, °) | a = 11.885, b = 10.654, c = 12.206; α = 90, β = 106.623, γ = 90 |
| Cell volume | 1481 ų, Z = 4 |
| Axial ratios | 1.1155:1:1.1457calculated from COD 1008812 |
| Source structure | COD 1008812 (Acta Crystallographica, Section B, 1978) — 1 of 4 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.564 | 4.848 | 2.83 | 5.694 | 2.576 | 2.969 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 75.6 | 59.2 | 38.6 | 35.1 | 27.8 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 1008812; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 1.71 g/cm³calculated from COD 1008812 |
|---|---|
| Hardness (Mohs) | 2-2.5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 1.69-1.72 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | gray, green, whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | earthy, resinous, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 381.37 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Na 12.06%, B 11.34%, O 71.32%, H 5.29% |
Classification
| Nickel-Strunz (10th) | 6.DA.10Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 6.DA.10Wikidata (CC0) |