Lanthanite-(Nd), Nd₂(CO₃)₃·8H₂O

Abstract

Lanthanite-(Nd), ideally Nd2(CO3)3·8H2O [dineodymium(III) tricarbonate octa­hydrate], is a member of the lanthanite mineral group characterized by the general formula REE 2(CO3)3·8H2O, where REE is a 10-coordinated rare earth element. Based on single-crystal X-ray diffraction of a natural sample from Mitsukoshi, Hizen-cho, Karatsu City, Saga Prefecture, Japan, this study presents the first structure determination of lanthanite-(Nd). Its structure is very similar to that of other members of the lanthanite group. It is composed of infinite sheets made up of corner- and edge-sharing of two NdO10-polyhedra (both with site symmetry ..2) and two carbonate triangles (site symmetries ..2 and 1) parallel to the ab plane, and stacked perpendicular to c. These layers are linked to one another only through hydrogen bonding involving the water mol­ecules.

Soaking the Rare-Earth Carbonates for a Change: An Alternative Approach to Explore Carbonate Nonlinear Optical Crystals

“…We choose to experiment with two major rare-earth carbonate structures, namely RE 2 (CO 3 ) 3 ·8H 2 O (RE = La–Nd) and RE 2 (CO 3 ) 3 ·2H 2 O (RE = Sm–Lu). − Structurewise, RE 2 (CO 3 ) 3 ·8H 2 O consists of RE-CO 3 2– layers, with crystalline water molecules positioned in between two neighboring layers and connecting them with hydrogen bonds . Similarly, RE 2 (CO 3 ) 3 ·2H 2 O is also a pseudolayer structure of RE-CO 3 2– layers, but with the layers connecting to each other via the carbonate groups .…”