Holmium polysulfide crystals: Structure, shape and composition

The variety of morphology, chemical composition and density of holmium polysulfide crystals grown from the flux in different as well as in the same experiments is observed. It was found that the crystals of different habits have the monoclinic structure, P21/m, a = 10.95, b = 11.45, c = 10.97 Å, β = 91.3°, as already known, and identical composition HoS1.837. All the crystals are twinned by the plane (101¯). It is shown that the diversity of crystal compositions and density values are due to the constitution of the flux in a crystal and displacement of a crystal in the growth zone. The formation of non-equilibrium growth forms is discussed.