Natrochalcite NaCu₂(SO₄)₂∙H₃O₂ from the Lavrion Mining District – a brief characterisation

Recently, samples of natrochalcite, NaCu₂(SO₄)₂∙H₃O₂, were discovered from the Esperanza Mine, Lavrion Mining District, Greece. In the present study this material is characterized by single crystal X-ray diffraction at ambient and LT conditions. Natrochalcite is monoclinic, space group C2/m, with a = 8.809(2), b = 6.196(1), c = 7.504(2) Å, β = 118.56(3)°, V = 359.7(1) ų, Z = 2, R1 = 0.0195 at room temperature. No symmetry change was observed down to 100K.