Tetrayttrium difluoride disilicate orthosilicate, Y4F2[Si2O7][SiO4]

Tetra­yttrium difluoride disilicate orthosilicate, Y4F2[Si2O7][SiO4]

In the crystal structure of Y4F2[Si2O7][SiO4], three fundamental building blocks are present, viz. anionic disilicate and orthosilicate units ([Si2O7](6-) and [SiO4](4-)) and cationic [F2Y4](10+) entities. The latter are built up by two [FY3](8+) triangles sharing a common edge. The four crystallographically independent Y(3+) cations display coordination numbers of eight for one and of seven fo...

Lithium Disilicate Glass-Ceramic

ceramic on light transmission of light-emitting diode (LED) and quartz-tungsten-halogen units (QTH) were evaluated. Ceramic IPS e.max CAD shades A1, A2, A3, A3.5, high (HT) and low (LT) translucency were cut (1, 2, 3, 4 and 5 mm). Light sources emission spectra were determined. Light intensity incident and transmitted through each ceramic sample was measured to determine light transmission perc...

Tetra­yttrium(III) tris­ulfide disilicate

Tetra-yttrium(III) tris-ulfide disilicate, Y(4)S(3)(Si(2)O(7)), crystallizes in the Sm(4)S(3)(Si(2)O(7)) structure type. The structure consists of isolated (Si(2)O(7))(6-) units (2mm. symmetry) and two crystallo-graphically independent Y(3+) cations bridged by one S and one O atom. The first Y atom (site symmetry .m.) is coordinated by three O atoms and three S atoms in a trigonal-prismatic arr...

Comparative Crystal Chemistry of Orthosilicate Minerals

Beryllium Diammine Difluoride [BeF2(NH3)2]

Beryllium difluoride BeF2 reacts with liquid ammonia forming discrete diammine difluoro beryllium(II) [BeF2(NH3)2] molecules. The colorless compound crystallizes in the monoclinic space group P21/c with a = 4.8815(2), b = 6.8528(3), c = 10.3690(5) Å, β = 92.01(1)◦ , V = 346.65(3) Å3 at 123 K with Z = 4. [BeF2(NH3)2] is the first structurally characterized example of a berylliumammonia complex. ...