Elena Sokolova

My life-long interest has been in the TS-block minerals (TS = Titanium-Silicate), a fascinating group of 50 very complex and often poorly crystalline minerals, commonly with very small crystals. The main structural unit of the TS-block structures is a TS block which consists of a central O sheet of edge-sharing octahedra between H sheets of Ti(Nb) polyhedra and Si2O7 groups. There are four groups of TS-block structures defined by different topology and stereochemistry of the TS block, and these groups also show a wide range of chemical compositions (Sokolova 2006). I solved the crystal structures of TS-block minerals from the Khibiny and Lovozero alkaline massifs of the Kola Peninsula, Russia, and the Darai-Pioz alkali massif in Tajikistan. My work on TS-block minerals culminated in the establishment of the IMA-approved seidozerite supergroup which contains more than 50 minerals of 24 topologically different structure types (Sokolova & Cámara 2017). I used TEM to show that some of the TS-block minerals show nanoscale intergrowths that can account for the observation of spectroscopic signals that are not consistent with the refined crystal-structures. My work on the TS-block minerals has resulted in a coherent chemical and structural hierarchy for a wide variety of different crystal structures and chemical compositions. This quantitative relation allows prediction of new structure topologies of TS-block minerals from chemical composition. In fact, two minerals that had been predicted, were later found in Nature; they are kolskyite and shkatulkalite. I have worked extensively on astrophyllite-group minerals, showing that there are three distinct structure types with different linkage between adjacent HOH blocks, describing six new minerals, and establishing the astrophyllite supergroup (Sokolova et al. 2017). To date, I have published 248 refereed papers and has been involved in the description of 71 new mineral species.

Sokolova, E. and Cámara, F. (2018) From structure topology to chemical composition. XXV: new insights into the close packing of cations in the structures of the seidozerite-supergroup TS-block minerals. Zeitschrift für Kristallographie, 233(3-4), 205-221.

Sokolova, E. and Cámara, F. (2017) The seidozerite supergroup of TS-block minerals: nomenclature and classification, with change of the following names: rinkite to rinkite-(Ce), mosandrite to mosandrite-(Ce), hainite to hainite-(Y) and innelite-1T to innelite-1A. Mineralogical Magazine, 81(6), 1457-1484.

Sokolova, E. and Cámara, F. (2013) From structure topology to chemical composition. XVI. New developments in the crystal chemistry and prediction of new structure topologies for titanium disilicate minerals with the TS block. Canadian Mineralogist, 51(6), 861-891.

Sokolova, E. (2012) Further developments in the structure topology of the astrophyllite-group minerals. Mineralogical Magazine, 76(4), 863-882.

Sokolova, E. (2006) From structure topology to chemical composition: I. Structural hierarchy and stereochemistry in titanium disilicate minerals. Canadian Mineralogist, 44, 1273-1330.