Tecnologia em Metalurgia, Materiais e Mineração
https://tecnologiammm.com.br/article/doi/10.4322/2176-1523.0854
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

CRESCIMENTO E CARACTERIZAÇÃO DOS CRISTAIS MISTOS (NH4)2NiXCu(1–X)(SO4)2.6H2O

[EN] GROWTH AND CHARACTERIZATION OF MIXED CRYSTALS (NH4)2NiXCu(1–X)(SO4)2.6H2O

Silva, Fabiane Leocádia da; Franco, Carlos Joel

Downloads: 0
Views: 314

Resumo

Cristais da família cristalográfica do sal de Tutton A2B(XO4)2.6H2O, A=K, NH4, Rb, Cs, Tl, B=Mg, Mn, Fe, Co, Ni, Cu, Zn, Cd, V, Cr, X=S e Se têm sido investigados por diversas técnicas experimentais com o objetivo de compreender suas propriedades físicas e potenciais aplicações tecnológicas. Investigações sobre o comportamento estrutural têm sido realizadas por difração de raios-x a fim de compreender suas propriedades estruturais, principalmente a distorção Jahn‑Teller presentes nos cristais com cromo e cobre. A estrutura dos cristais desta série à temperatura ambiente é monoclínica, grupo espacial P21/a com duas moléculas por célula unitária. Bons monocristais da série (NH4)2NixCu(1–x)(SO4)2.6H2O com 0< x <1 foram obtidos em todo o intervalo de composição. Os resultados do crescimento dos cristais, das medidas de difração de raios-x, microscopia óptica e microscopia de força atômica foram obtidos para estes cristais. Dados de difração de raios-x revelam que a estrutura das amostras com x em torno de 0,5 apresenta-se com forte distorção quando comparada com aquelas de baixos ou altos valores de x.

Palavras-chave

Cristais mistos, Difração de raios-x, Microscopia óptica, Microscopia de força atômica.

Abstract

Crystals of the family of crystallographic Tutton salt A2B(XO4)2.6H2O, A=K, NH4, Rb, Cs, Tl, B=Mg, Mn, Fe, Co, Ni, Cu, Zn, Cd, V, Cr, X=S e Se has been investigated by various experimental techniques in order to understand their physical properties and potential technological applications. Investigations on the structural stability have been performed by x-ray diffraction in order to understand their structural properties, mainly the Jahn-Teller distortion present in the crystals with chromium and copper. The crystal structure of this series at room temperature is monoclinic, space group P21/a with two molecules per unit cell. Results of crystal growth series (NH4)2NixCu(1–x)(SO4)2.6H2O with 0 < x <1 and results of measurements of X ray diffraction, optical microscopy and Atomic force microscopy were obtained. Crystals of this family were obtained over the entire range of composition, though for higher concentrations of copper exhibit milky appearance. Data X ray diffraction revealed that the structure of the samples with x around 0.5 is presented with strong distortion when compared with those of low or high values of x.

Keywords

Mixed crystals, X Ray diffraction, Optical microscopy, Atomic force microscopy.

Referências

1 Chen Z, Fei S, Strauss HL. Switching the Jahn−teller distortion in crystalline ammonium hexaaquacopper sulfate (Tutton salt) with infrared radiation. Journal of the American Chemical Society. 1998;120(34):8789-8796. http://dx.doi.org/10.1021/ja980782k.

2 Dobe C, Carver G, Bürgi HB, Tregenna-Piggott PL, McIntyre GJ, Augustyniak-Jablokow MA, et al. Low-temperature single-crystal Raman and neutron-diffraction study of the hydrogenous ammonium copper(II) Tutton salt and the deuterated analogue in the metastable state. Inorganic Chemistry. 2003;42(25):8524-8533. http://dx.doi.org/10.1021/ic0343511. PMid:14658909.

3 Andreeta JP. Cristalização: teoria e prática. São Carlos: IFSC-USP; 2000.

4 Brown GM, Chidambaram R. The structure of copper ammonium sulfate hexahydrate from neutron diffraction data. Acta Crystallographica. Section B, Structural Crystallography and Crystal Chemistry. 1969;25(4):676-687. http://dx.doi.org/10.1107/S0567740869002810.

5 Kirfel A, Klapper H, Schäfer W, Schwabenländer F. The crystal structure of Tutton’s salt type K 2 [Co(H 2 O) 6 ] (SO 4 ) 2. A combined X-ray and neutron study. Kristallogr. 1998;213(9):456-464. http://dx.doi.org/10.1524/zkri.1998.213.9.456.

6 Bokiy GB. Crystal chemistry. 3rd ed. Moscow: Nauka, 1971. 400 p.

7 Cotton FA, Daniels LM, Falvello LR, Murillo CA, Schultz AJ. Solid solutions of Jahn-Teller compound in an undistorded host. 4. Neutron and X-ray single crystal structures of two Cr/ZnTutton Salt solid solutions and the observation of disorder by low- temperature neutron diffraction. Inorganic Chemistry. 1994;33(24):5396-5403.

8 Marinova D, Georgiev M, Stoilova D. Vibration behavior of matrix-isolated ions in Tutton compounds. II. Infrared spectroscopic study of NH4+ and SO4–2 ions included in copper sulfates and selenates. Journal of Molecular Structure. 2009;938(1-3):179-184. http://dx.doi.org/10.1016/j.molstruc.2009.09.023.

9 Georgiev M, Marinova D, Stoilova D. Vibration behavior of matrix-isolated ions in Tutton compounds.III. Infrared spectroscopic study of NH4+ and SO4-2 ions included in copper sulfates and selenates. Vibrational Spectroscopy. 2010;53(2):233-238. http://dx.doi.org/10.1016/j.vibspec.2010.03.014.
588696ff7f8c9dd9008b47c4 tmm Articles
Links & Downloads

Tecnol. Metal. Mater. Min.

Share this page
Page Sections