A Tungstate Chemical Garden

Abstract

Tungstate chemical gardens have been prepared for the first time. The synthesis was carried out using cobalt(II) chloride and sodium tungstate. The reaction occurred in three steps: chimney formation, swelling, and upwelling of the chemical garden. This result opens the door to a new variety of materials. Chemical gardens are fascinating self-organizing inorganic structures consisting mainly of tubes and vesicles, which biomimic plant-like structures. From a first description by Johann Glauber in 1646, [1] chemical gardens have attracted attention. In the last few years, scientists have been interested in chemical gardens to explore a wide variety of scientific questions. This research field has been recently called chemobrionics. [2] There is a great variety of subjects that can be studied through chemobrionics, e. g., corrosion, electrochemistry, sensors, and chemical motors. [2,3] One of the most interesting scientific questions in the ambit of chemobrionics is the origin of life, since life could have originated in oceanic hydrothermal vents, which are natural chemical gardens. [2,4-8] Experiments to promote the formation of classical chemical gardens consist in adding to a solution of an anion a metal salt (all except the too-soluble alkali metals), in solid form of single crystals or as polycrystalline powder compressed into a pellet, or alternatively as a second liquid. A number of different solutions and metals have been shown to lead to the growth of chemical gardens. [2] In the solution, the commonest anion used is silicate, but many other anions have been also used: e. g., carbonate, phosphate, borate, arsenate and chromate. [2] Metals used to precipitate chemical gardens have been, e. g., Ca, Mg, Co, Ba, Fe, Cu and Zn, just to mention a few. [2,9] Interestingly, the growth of chemical gardens using crystals of anions and solutions of cations have also been reported. [2,10] These kinds of inverted systems have been described for polyoxometalates (POMs). [9] POMs are complexes with polyatomic ions, which can contain W, Mo, Mn, P, or Si in their structure.

Dark-induced vertical growth of chemobrionic architectures in silver-based precipitating chemical gardens

“…Chemical gardens is a term often used to describe inorganic precipitates that resemble plant like growth, and these structures grow within minutes or hours of plunging metal ion salts into anionic solutions. 1–12 Though the chemical gardens are entirely composed of inorganic moieties, they have a biologically imitative look arising from their non-equilibrium architectures. The plant like or tube-like precipitation in the chemical gardens is a consequence of the diffusive translocation of ionic species upon osmotic imbalance arising in the reaction mixture.…”

Downward fingering accompanies upward tube growth in a chemical garden grown in a vertical confined geometry

“…Classical experiments of 3D gardens grown from a seed are still carried out by many scholars and have produced a lot of important results. 68–72 Typically, the procedure involves placing a seed crystal of metal salt at the bottom of the vessel and filling it with solution. Thereafter, precipitation occurs around the seed and forms a semi-permeable membrane, and we will then observe tubular filaments just like the upward-growing tubes reported in this paper.…”

Investigation of electronic structure, morphological features, optical, colorimetric, and supercapacitor electrode properties of CoWO4 crystals

“…This mineral, also known as ''Krasnoselskite", has been explored at Krasnoselskaya mines in Krasnogorsk, Chelyabinsk basin, Ural Mountains in Russia [2,3]. According to the literature [4], CoWO 4 crystals are not recognized as a natural mineral by the International Mineralogical Association (IMA) [5,6]. These crystals are oxides belonging to the wolframite family [7] with a general formula (AWO 4 ) (A = Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , and Zn 2+ ), space group (P2/c), symmetry point group (C 4 2h Þ, two molecular formula units per unit cell (Z = 2) and n°13 in the international crystallography table [8][9][10][11][12].…”