ИСТИНА

The chemistry of low-dimensional magnets is rapidly evolving into a vast ar- ea of research. Presence of ions with non-compensated spins (e.g. Cu2+ d9, S = ½) is a necessary condition for the desired properties. The probability of forming a low-dimensional magnet system is high when the crystal structure is also low- dimensional. The compounds with a kagome-related net, A2Bcu3F12 (А = univalent, В = tetravalent cation) are prospective candidates, but their magnetic properties dif- fer substantially for various sets of A and B [1]. The objects of the current study are the compounds with А = Rb, Cs, and B = Sn, Ti, Zr. To find out the relationships between chemical composition, crystal structure, and magnetic properties, single-phase specimens (or those free from magnetic admixtures: fluorinated copper compounds or their hydrolysis products), or single crystals, are required. We employed solid-state routes from binary fluo- rides. Pelletized samples were annealed in argon-filled sealed copper tubes together with small amounts of xenon fluoride XeF2 as a fluorinating agent. All operations before annealing were performed in an argon-filled glovebox (H2O<1 ppm). The compounds Rb2ZrCu3F12 and Cs2-xRbxSnCu3F12 (x = 0.5, 1.0, 1.5) were prepared for the first time. The annealing protocol was established experimentally. For ex- ample, single crystals of Rb2ZrCu3F12 were prepared at 650ºС within 120 hrs. All synthesized compounds A2Bcu3F12 (А = Rb, Cs, and B = Sn, Ti, Zr) were diag- nosed by X-Ray diffraction and by magnetic susceptibility measurements in a wide temperature range. The Russian team was supported by RFBR, research projects no. 14-03- 00604-а, 12-03-00665-a and 12-03-92604-KO-a. The UK team weas supported by an Royal Society International Exchanges grant.