Growth and properties of ferroelectric potassium ferrocyanide trihydrate single crystals

Abstract

Single crystals of potassium ferrocyanide trihydrate, K 4 [Fe(CN) 6 . 3H 2 O (KFCT), a ferroelectric material with Curie temperature 251K were grown in silica gel at room temperature for the first time by the solubility reduction method. Resorcinol and ethyl alcohol were used for the purpose of gel setting and supernatant liquid respectively. Optical and mechanical properties were studied for the grown crystal. The structure of the grown crystal was confirmed by X-ray diffraction analysis. Fourier Transform Infrared (FTIR) and FT Raman spectral analysis of the crystalline samples reveal that the crystalline sample consist consists of all functional groups. Thermal analysis of the crystalline sample was performed by TGA and DTA methods. The Vicker's micro hardness value was measured for KFCT crystals. The square etch pits with a hopper-like structure is an indicative of 2D nucleation mechanism.

Growth and characterization of pure and doped NLO L-arginine acetate single crystals

“…The crystal is completely free of any water of crystallization or any physically adsorbed water on the surface. The absence of significant band in the region 3500-3400 cm -1 confirms the absence of water molecule (Kanagadurai et al 2006 …”

Effect of Nanoscale Confinement on the Crystallization of Potassium Ferrocyanide

“…50 The IR spectrum of the ethanol-precipitated samples containing needle-shaped crystals was distinctly different (Figure 3b). The major OH-bands in a range 3300-3600 cm -1 were very weak, the 1614 cm -1 OH bands were significantly reduced in intensity and new peaks in the CN-region at 2093, 2072, 2017 and 2041 cm -1 were observed.…”

“…This progression in crystal morphologies is consistent with descriptions of crystals of KFCT in the literature, which assigns the rectangular prismatic crystals to the monoclinic polymorph. 50 The crystal structures of the different morphological forms of KFCT were then investigated using Raman microscopy and infrared spectroscopy (IR), powder X-ray diffraction (PXRD) and TEM selective area electron diffraction (SAED) to determine their polymorphs, where the assignments are summarized in Table 1. Samples for IR and PXRD analyses were recovered by filtration, where this was carried out 1 min after initiation of the reaction in the ethanol precipitation, and after 3 min from the evaporating solutions.…”

Synthesis and structure of some nano-sized rare-earth metal ions doped potassium hexacyanoferrates

“…Such a double peak occurring near 2100 cm À 1 is a characteristic of cyanide stretching in reduced octahedrally coordinated iron-cyanide complexes [23]. In KFCN crystals, this double peak occurs around 2071 and 2100 cm À 1 and has been assigned to the cyanide stretching mode [1]. In comparison, the two peaks in the doublet observed in the Raman spectra of KR-HCF nanoparticles have apparently moved closer to each other.…”

“…Potassium hexacyanoferrate [KHCF or K Fe( CN ) 3H O 4 6 2 · ], or potassium ferrocyanide-trihydrate (KFCT), belongs to a family of crystals with a general formula A [B( CN ) ] 3H O 4 6 2 · , with A≡K or NH 3 ; and B Fe, Mn, Ru,Os ≡ [1]. A group of variants of KHCF, called the 'potassium-metal-hexacyanoferrates (KM-HCF)', or 'metal-hexacyanoferrates (MHCF)', can be obtained through the replacement of some, or all potassium atoms with metal ions (such as, Cu, Co, Ni, Cr, etc.…”