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Three new microporous compounds with octahedral-pentahedral-tetrahedral framework structures (so called OPT materials) with metalophosphate composition were prepared under solvothermal conditions and characterized by X-ray diffraction and Mössbauer spectroscopy. Ironalumino- and irongallophosphates are violet and brown-violet crystals with NH4[Fe1.15Al1.85P3O12](H2O)2 and NH4[Fe1.05Ga1.95P3O12] (H2O)2 composition. Nickelgallophosphate NH4[Ni1.0Ga2.0P3O12](H2O)2 forms light yellow lozenges. All products have isotype crystal structures in space group C2/c. The framework structures are built of corner- and edge-sharing distorted octahedra, trigonal bipyramids and phosphate tetrahedra. Iron occurs in two different valence states and occupies different polyhedra types in the structures, confirmed by Mössbauer spectroscopy. The compounds have three-dimensional channel systems which are filled by ammonium groups and water molecules, forming a strong hydrogen bonding system. Upon heating, the frameworks collapse during deammonization at temperatures below 573 K. A deformation analysis of the different coordination polyhedra in comparable compounds was performed and the structural relationship to a similar ammonium gallophosphate is discussed.

New, remarkably dry parts of the Gamslöcher-Kolowrat Cave at 728 to 853 m depth have been explored in the Untersberg near Salzburg in Austria. This region is called the Desert, its greatest cavity is called the White Hall. The new cave part is characterized by various white speleothems. The predominant ones are snow-like calcite powder with an extremely low density, and fine gypsum needles. Gypsum also occurs in the form of balls stuck to vertical walls. In addition, fluorescent hydromagnesite crusts, Mg 5 (CO 3 ) 4 (OH) 2 ·4H 2 O, as well as the sodium sulfate mineral mirabilite were identified in this part of the cave. Mirabilite and gypsum needles differ from the gypsum balls in their isotopic sulfur signature (δ 34 S of -16.9‰ and -18.4‰ vs. +2.9‰). The unusually low sulfur isotopic compositional values are tentatively explained by a source of bacteriogenetic sulfur from sulfides.