Lucky Number 13: A 13-Layer Polytype of the Alkyne Hydrogenation Catalyst CaGaGe.

Polytypism, the ability of materials to form crystal structures with different stacking sequences, occasionally causes materials with the same stoichiometry and similar local structures to have profoundly different properties. Herein, we discover a metastable 13-layer trigonal (13T) polytype of CaGaGe, a layered intermetallic phase comprised of [GaGe] honeycombs separated by Ca. 13T-CaGaGe is synthesized from arc-melting the elements, and its structure is elucidated via neutron powder diffraction.

RbInCl: A Monoclinic Double Perovskite Derivative with Bright Sb-Activated Photoluminescence.

Here, we present the synthesis and crystal structure of RbInCl prepared from air stable reagents via a two-step process that proceeds through the intermediate RbInCl·HO. RbInCl crystallizes with the RbYCl structure type (2/), which can be derived from the double perovskite structure by noncooperative tilting of isolated [InCl] octahedra. Despite this lowering of symmetry, the optical properties are similar to the cubic double perovskite CsNaInCl.

Broadband White Emission in CsAgInBiCl Phosphors.

The photoluminescent properties of the lead-free double perovskite solid solution CsAgInBiCl have been investigated. The In end member, CsAgInCl, is a direct gap semiconductor that absorbs UV light (λ < 350 nm) and shows little to no photoluminescence. Incorporation of Bi leads to a strong sub-band gap absorption that peaks in the near UV (∼360 nm) and extends into the visible.