The crystal structure of Ba_2F_2(S~(6+)O_3S~(2-)), a natural thiosulphate weathering product of old smelting slags at the Surrender Mill, Yorkshire, UK

摘要

The crystal structure of Ba_2F_2(S~(6+)O_3S~(2-), a natural thiosulphate weathering product of old smelting slags at the Surrender Mill, Yorkshire, England, UK, has been solved to R = 0.88 percent for 399 unique [F_00000 > 4 sigma F] reflections and 0.91 percent for all 407 reflections. The compound is monoclinic, C2/m, a 15.3172(5), b 4.5898(1), c 4.6320(2) A, (3 101.449(1) deg, V 319.17(2) A~3. The structure of Ba_2F_2(S~(6+)O_3S~(2-)) consists of BaF_2Ba layer fragments of the fluorite-type structure of frankdicksonite (BaF_2) parallel to (100) alternating with layers of thiosulphate groups. The layer sequence in one unit cell is (S~(6+)O_3S~(2-))-BaF_2Ba-(S~(6+)O_3S~(2-))-BaF_2Ba. The structure resembles that of grandreefite, Pb_2F_2SO_4.