Topic
Susannite
About: Susannite is a research topic. Over the lifetime, 12 publications have been published within this topic receiving 117 citations.
Papers
TL;DR: The crystal structure of macphersonite (Pb 4 SO 4 (CO 3 ) 2 (OH) 2, Pcab, a = 9.242(2), b = 23.050(5), c = 10.383(2) Aa) from Leadhills, Scotland has been determined to an R = 0.053 as discussed by the authors.
Abstract: The crystal structure of macphersonite (Pb 4 SO 4 (CO 3 ) 2 (OH) 2 , Pcab, a = 9.242(2), b = 23.050(5), c = 10.383(2) Aa) from Leadhills, Scotland has been determined to an R = 0.053. The structure has many features in common with its polymorph leadhillite including three distinct types of layers. Layer A includes sulphate tetrahedra, Layer B is composed of Pb and OH, while Layer C is composed of Pb and CO 3 with topology identical to that in cerussite. In both macphersonite and leadhillite these layers are stacked along [010] as ...BABCCBABCC... The double CC layer is almost identical in the two structures and forms a structural backbone and occurs in other structures including hydrocerussite and plumbonacrite. The sulphate layer shows the greatest difference between the two structures and can be described by a pattern of up or down pointing tetrahedra. For macphersonite the sequence along [001] is ...UDUDUD... while in leadhillite the sequence along [010] is ...UDDUUDDU... This latter sequence effectively doubles b relative to the equivalent direction in macphersonite. Susannite, a third polymorph, may have yet another sequence of sulphates to give trigonal symmetry; by heating leadhillite, displacive movements of sulphate groups may occur with a conversion to susannite.
25 citations
TL;DR: In this article, the authors measured the Raman spectrum of the basic carbonate-sulphate minerals known as leadhillite, susannite, and caledonite and compared the spectra of these minerals with those of cerussite, hydrocerussite and anglesite.
Abstract: The Raman spectrum of the basic carbonate-sulphate minerals known as leadhillite, susannite and caledonite have been measured and the spectra compared with the Raman spectra of cerussite, hydrocerussite and anglesite. Characteristic spectral patterns are observed for each mineral. The wavenumber position of the hydroxyl stretching bands is used to estimate the hydrogen bond distances in the minerals. The hydrogen bond distances for leadhillite polymorphs vary from 2.783 to 2.916 A. In comparison the estimated hydrogen bond distances for hydrocerussite are much longer with values of 2.961 and 3.127 A. The width of the hydroxyl stretching vibration provides an estimate of the variation of hydrogen bond distances for the OH groups in the mineral. The variation in bond length is greater for the longer hydrogen bonds. Characteristic sulphate and carbonate vibrations are also identified.
23 citations
TL;DR: Mattheddleite as discussed by the authors is a lead member of the apatite group with sulphur and silicon totally replacing phosphorus, occurs as tiny crystals (a 9.96 g/cm 3 ).
Abstract: Synopsis Mattheddleite, a new lead member of the apatite group with sulphur and silicon totally replacing phosphorus, occurs as tiny crystals ( a 9.963 and c 7.464 A (the cell volume is 642 A 3 ). The calculated density is 6.96 g/cm 3 . The strongest lines in the powder pattern are [ d , ( I ) ( hkl )]: 2.988 (100) (112, 211), 4.32 (40) (200), 4.13 (40) (111), 2.877 (40) (300), 3.26 (30) (210). Single crystal Weissenberg photographs are close to those of pyromorphite, space group P6 3 /m. Chemically, mattheddleite does not contain S and Si in the expected 1:1 ratio, and the ideal formula may be expressed as Pb 20 (SiO 4 ) 7 (SO 4 ) 4 Cl 4 . The infrared spectrum is very similar to that of hydroxyellestadite. Associated minerals are lanarkite, cerussite, hydrocerussite, caledonite, leadhillite, susannite, and macphersonite. The mineral is named after Matthew Forster Heddle (1828–1897), a famous Scottish mineralogist.
20 citations
TL;DR: Macphersonite as discussed by the authors is a polymorph of leadhillite and susannite and has a perfect cleavage on {010}. Optically it is negative with 2Vα 35-36°, α = 1.87, β = 2.00 and γ = 0.10.
Abstract: Macphersonite is white, resinous to adamantine, hardness (Mohs) 2½−3, density 6.50–6.55 gm/cm3 and possesses a perfect cleavage on {010}. Optically it is negative with 2Vα 35–36°, α = 1.87, β = 2.00 and γ = 2.01, α = b, γ = c, and γ = a, dispersion r > v. Polysynthetic twinning, with either coarse or fine lamellae, is common, as are contact twins. Crystals are orthorhombic, tabular on b with a 10.37, b 23.10 and c 9.25 A, cell volume 2215.8 A3 and space group Pcab; Z is 8 formula units. The seven strongest lines in the X-ray powder pattern are 3.274 (50) 052; 3.234 (100) 251; 2.654 (90) 351,203; 2.598 (30) 172, 400; 2.310 (30) 004, 371, 0.10.0; 2.182 (30) 263; and 2.033 (30) 234, 452, 154, 1.10.2. Electronprobe-microanalysis-determined chemistry leads to the empirical formula (Pb4.08, Cu0.10, Cd0.07)Σ4.25S0.90 C2.18O10.55(OH)1.58 which yields the ideal formula Pb4(SO4)(CO3)2(OH)2 and hence macphersonite is a polymorph of leadhillite and susannite. The infrared spectrum shows basic similarities to leadhillite and susannite spectra with additional diagnostic absorption bands. Macphersonite shows an identical thermogravimetric behaviour to that of leadhillite. It is associated, in varying combinations, with leadhillite, susannite, cerussite, caledonite, pyromorphite, scotlandite, galena, and the ‘lead hydroxyapatite’ of Temple (1955). The new mineral mimics leadhillite.
15 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2005 | 1 |
| 2003 | 1 |
| 1999 | 1 |
| 1998 | 1 |
| 1990 | 1 |
| 1987 | 1 |