| Abstrakt: |
AbstractSweetite, naturally occurring Zn(OH)2with tetragonal symmetry, has been found at Milltown, near Ashover, Derbyshire. It occurs as colourless or whitish bipyramids up to 1 mm in size scattered over the surface of colourless fluorite cubes. The cell dimensions are a 8,222 and c14.34Å with Z= 20. The strongest lines of the X-ray powder pattern are (d, I, hkl): 4.53 37 (112); 3.572 60 (004,202,211); 2.922 100 (213,220); 2.708 18 (105,204); 2.257 17 (224,215,321); 1.840 11 (226,420,413); 1.764 24 (316). Sweetite is uniaxial negative, ?1.635, ?1.628. Dmeasis close to 3.33 and Dcalc3.41. Chemical analysis gave 84.3% ZnO and 17.0% H2O, while theoretical figures for Zn(OH)2are 81.9 and 18.1% respectively. |
