Download citation
Acta Cryst. (2014). A70, C1099
Download citation
link to html
Sulfates and phosphates consisting of mixed anionic radicals (or heteropolyhedral units) constitute a large group of mineral species. In this contribution, we will summarize our recent results on some novel or poorly studied minerals, whose structures are based upon octahedral-tetrahedral structural units. During investigations of secondary pegmatite phosphates from Hagendorf (Germany), we have located a new whiteite-jahnsite-group mineral that was named whiteite-(CaMnMn) Its structure is formed by alternating anionic layers composed from MO6 octahedra and PO4 tetrahedra, and linked together thorugh M(2) cations and water molecules. The crystal structure of bonshtedtite, Na3Fe(PO4)(CO3), is similar to that of the other minerals of the bradleyite group. It is based upon the [Fe(PO4)(CO3)]3- layers oriented parallel to (001). Refinement of the crystal structure of girvasite at 110 K allowed to determine positions of H atoms and to reveal the hydrogen bonding scheme. The refinement confirmed that the proper chemical formula of the mineral should be written as NaCa2Mg3(PO4)4(CO3)(H2O)6, in contrast to the formula NaCa2Mg3(PO4)2[PO2(OH) 2](CO3)(OH)2(H2O)4 proposed in the original works. The crystal structure of cattiite, Mg3(PO4)2(H2O)22 contains two symmetrically independent Mg sites, tetrahedrally coordinated by water molecules to form octahedral complexes [Mg(H2O)6]. The crystal structure of vendidaite, Al2(SO4)(OH)3Cl(H2O)6, contains one symmetrically independent Al site coordinated by three OH groups and three H2O molecules. Together with the [Al2(OH)3(H2O)6]3+ chains, Cl- anions and (SO4)2- groups form pseudo-layers parallel to (010).Steklite, KAl(SO4)2, was first described as a technogenic phase in products of burning coal dumps (Chelyabinsk region, Russia). Steklite of natural origin was found in sublimates of the Yadovitaya (Poisonous) fumarole of the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Kamchatka, Russia.

Follow Acta Cryst. A
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds