Abstract
Campigliaite, a new copper and manganese sulfate mineral, occurs as tufts of light blue crystals in the sulfide ore bodies of Temperino mine, Campiglia Marittima, Tuscany, Italy. It is monoclinic, space group C2, with a = 21.707, b = 6.098, c = 11.245Å, β = 100.3°. The tiny crystals, elongated [010] and flattened {100}, are always twinned (100). The calculated density is 3.06 g cm−3. Optically it is biaxial (−) with α = 1.589, β = 1.645, γ = 1.659. The strongest lines in the X-ray powder pattern are 10.68(100)(200), 5.34 (60)(400), 3.56 (44)(600), 2.673(5)(022 and 800).
The structure was solved using 689 independent reflections and refined to an R value of 0.124. The dominant structural feature is the arrangement of copper–oxygen polyhedra into dense sheets, parallel to (100). The sulfate groups are linked by a comer to both sides of sheets. The Mn atom coordinates four water molecules and two oxygen atoms of sulfate groups belonging to the same Cu–O–S layer. Subsequent layers are connected to each other by hydrogen bonds. The relationship between the structures of campigliaite and devillite and serpierite is discussed.
