Iodide-Iodates M[IO]·AgI, M = Bi, Tb, with a Framework Structure and High Second-Harmonic Generation Optical Response.

Single crystals of two new iodide-iodates, Bi[IO]·AgI and Tb[IO]·AgI, are synthesized in hydrothermal systems. The anionic parts in both iodide-iodates are characterized as a complex charged framework of isolated IO umbrella-like groups and large Bi(Tb)-O polyhedra similar to those previously found in La[IO][IO](PbO). Broad channels along the c-axis contain compensators: (AgI) umbrella-like groups and additional Ag ions which form Ag tetrahedral clusters augmented with I halogen.

Modulated structure of Lu4AlCu2B9O23 from low-temperature single-crystal X-ray data.

A second-order phase transition with both displacive and disorder mechanisms was discovered in Lu4AlCu2B9O23 using single-crystal X-ray diffraction techniques by cooling down the sample to 110 K. Low-temperature structure modulations are mainly associated with Cu atoms surrounded by O atoms. The fivefold asymmetric environment leads to a special copper position splitting into a pair of general ones so that four O atoms coordinate each of them.

Acentric polyborate, Li3[B8O12(OH)3], with a new type of anionic layer and Li atoms in the cavities.

Single crystals of Li3[B8O12(OH)3] were synthesized under hydrothermal conditions using a complex initial composition that included SiO2. The crystal structure is acentric, space group P62c, with a = 8.9301(2) Å and c = 15.