Hydrothermal Formation of Calcium Copper Tetrasilicate

Darrah Johnson-McDaniel; Sara Comer; Joseph W Kolis; Tina T Salguero

doi:10.1002/chem.201503364

Hydrothermal Formation of Calcium Copper Tetrasilicate

Chemistry. 2015 Dec 1;21(49):17560-4. doi: 10.1002/chem.201503364. Epub 2015 Oct 20.

Authors

Darrah Johnson-McDaniel¹, Sara Comer², Joseph W Kolis², Tina T Salguero³

Affiliations

¹ Department of Chemistry, The University of Georgia, 140 Cedar Street, Athens, GA 30602 (USA).
² Department of Chemistry, Clemson University, 219 Hunter Laboratories, Clemson, SC 29634 (USA).
³ Department of Chemistry, The University of Georgia, 140 Cedar Street, Athens, GA 30602 (USA). salguero@uga.edu.

PMID: 26482329
DOI: 10.1002/chem.201503364

Abstract

We describe the first hydrothermal synthesis of CaCuSi4 O10 as micron-scale clusters of thin platelets, distinct from morphologies generated under salt-flux or solid-state conditions. The hydrothermal reaction conditions are surprisingly specific: too cold, and instead of CaCuSi4 O10 , a porous calcium copper silicate forms; too hot, and calcium silicate (CaSiO3 ) forms. The precursors also strongly impact the course of the reaction, with the most common side product being sodium copper silicate (Na2 CuSi4 O10 ). Optimized conditions for hydrothermal CaCuSi4 O10 formation from calcium chloride, copper(II) nitrate, sodium silicate, and ammonium hydroxide are 350 °C at 3000 psi for 72 h; at longer reaction times, competitive delamination and exfoliation causes crystal fragmentation. These results illustrate that CaCuSi4 O10 is an even more unique material than previously appreciated.

Keywords: crystal engineering; crystal growth; hydrothermal synthesis; layered compounds; silicates.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.