The document summarizes the process of obtaining and analyzing the infrared (IR) spectrum of potassium ferricyanide using Fourier transform infrared (FT-IR) spectroscopy. It first discusses potassium ferricyanide and the principles of IR and FT-IR spectroscopy. It then describes sample preparation and the hands-on process of obtaining the IR spectrum. Key peaks in the spectrum are identified, including peaks attributed to lattice water and vibrational modes of cyanide and iron-cyanide groups. The IR spectrum is then analyzed to identify functional groups present in the compound.
The document summarizes the process of obtaining and analyzing the infrared (IR) spectrum of potassium ferricyanide using Fourier transform infrared (FT-IR) spectroscopy. It first discusses potassium ferricyanide and the principles of IR and FT-IR spectroscopy. It then describes sample preparation and the hands-on process of obtaining the IR spectrum. Key peaks in the spectrum are identified, including peaks attributed to lattice water and vibrational modes of cyanide and iron-cyanide groups. The IR spectrum is then analyzed to identify functional groups present in the compound.
The document summarizes the process of obtaining and analyzing the infrared (IR) spectrum of potassium ferricyanide using Fourier transform infrared (FT-IR) spectroscopy. It first discusses potassium ferricyanide and the principles of IR and FT-IR spectroscopy. It then describes sample preparation and the hands-on process of obtaining the IR spectrum. Key peaks in the spectrum are identified, including peaks attributed to lattice water and vibrational modes of cyanide and iron-cyanide groups. The IR spectrum is then analyzed to identify functional groups present in the compound.
The document summarizes the process of obtaining and analyzing the infrared (IR) spectrum of potassium ferricyanide using Fourier transform infrared (FT-IR) spectroscopy. It first discusses potassium ferricyanide and the principles of IR and FT-IR spectroscopy. It then describes sample preparation and the hands-on process of obtaining the IR spectrum. Key peaks in the spectrum are identified, including peaks attributed to lattice water and vibrational modes of cyanide and iron-cyanide groups. The IR spectrum is then analyzed to identify functional groups present in the compound.
Potassium ferricyanide obtained from FT-IR - TANYA SHARMA (Inorganic Group-3) 01 02 Theory Sample Preparation
03 Hands-on operation to obtain IR spectrum and spectrum analysis 01 THEORY ▪ Potassium ferricyanide
▪ Infrared Spectroscopy
▪ FT-IR Spectroscopy Potassium ferricyanide
Potassium ferricyanide is a chemical compound with a chemical formula K3[Fe(CN)6].
It is manufactured by passing chlorine through a solution of potassium ferrocyanide. Potassium ferricyanide thus separates from the solution. Infrared Spectroscopy Infrared Spectroscopy is an important branch of spectroscopy which can identify particular functional groups present in a molecule. It works on the principle that the molecules vibrate at specific frequencies and these frequencies fall in IR portion of electromagnetic spectrum. When IR radiation is incident on a sample, it absorbs radiations at frequencies similar to its molecular vibration frequencies and transmit other frequencies. Frequencies of absorbed radiation are detected by infrared spectrometer, and a plot of absorbed energy against frequency called as ‘infrared spectrum’, can be obtained. Only those molecular vibrations appear in the IR spectrum which are IR active (or absorb IR light). FT-IR Spectroscopy FTIR stands for Fourier Transform Infrared, the preferred method for infrared spectroscopy.
FTIR is a technique that uses infrared light to observe
properties of a solid, liquid or gas. It works on the principle of vibrational spectroscopy.
It is used in many different applications to measure the
absorption, emission and photo-conductivity of matter by shining a narrow beam of infrared light at the matter in various wavelengths and detecting how the matter responds to each wavelength. Once the data has been obtained, it is converted into digital information using a mathematical algorithm known as the ‘Fourier Transform’. Diagrammatic representation of FT-IR Michelson Interferometer 02 SAMPLE PREPARATION Sample Preparation
For recording IR Spectra, the sample should be properly dried as
water absorb near 3710 and 1630 cm-1.The sample should be perfectly dried, since cell materials (NaCl, KBr) are usually spoiled by the moisture. There are several methods by which a solid sample can be prepared.
(a) As a pressed disc: It involves the mixing of sample with powdered
KBr. A translucent pellet of this powder mixture is formed by pressing it in a mechanical pressure. The main advantage of using KBr is that it does not interfere with the bands due to compound since KBr is transparent to IR and thus give better spectra. Sample Preparation
(b) As a mull or paste: Finely ground compound is mixed with an oily mulling agent (usually Nujol) using a pestle and mortar. A thin film of the mull is placed between two flat plates of NaCl and the spectrum is measured. The main disadvantage of this method is that nujol has absorption bands at 2924- 2860, 1462, 1380 cm-1, therefore no information about the observed compound can be obtained in this region. (c) As a film: The third method is to dissolve the solid sample in a non- hygroscopic solvent usually methylene chloride or carbon tetrachloride. A drop of this solution is deposited on surface of KBr or NaCl plate. The solution is then evaporated to dryness and the film thus formed on the KBr disc is analysed directly to obtain the IR spectrum. 03 HANDS- ON OPERATION TO OBTAIN IR SPECTRUM AND ITS ANALYSIS Hands- on operation to obtain IR spectrum of Potassium ferricyanide
❑ First step is sample preparation which has already been discussed.
❑ The second step is to obtain an interferogram of the background which consists of the IR- active atmospheric gases carbon dioxide and water vapours. This interferogram gives the spectrum of background. ❑ In the third step, spectrum of the sample under investigation is obtained by the same procedure. This spectrum contains absorption bands from the sample as well as the background. ❑ The ratio between the single beam sample spectrum and the single beam background spectrum gives the spectrum of the sample. Computer software automatically subtracts the spectrum of the background from the sample spectrum. ❑ Finally the data obtained is analysed by assigning the observed absorption frequency bands in the sample spectrum to appropriate normal modes of vibrations in the molecules. Absorbance Infrared(IR) Spectra
The thermal coefficient of potential should be small. Infrared Spectra
CREDITS: This presentation template was created
by Slidesgo, including icons by Flaticon,and infographics & images by Freepik. Peak Identification FTIR of K3 [Fe(CN)6 ] as shown in figure exhibit peaks at (3464 cm-1, 1630 cm-1 ), (2118, 2076, 2043) cm-1 and 511 cm-1 which are attributed to ν (OH) of lattice water (symmetric and antisymmetric) (H-O-H), ν(C≡N) and ν (Fe-CN) vibrational % Transmittance
modes respectively. Analysis of IR spectrum of Potassium ferricyanide
The IR spectrum is divided into three wavenumber regions: far-IR spectrum (<400 cm-1), mid- IR spectrum (400-4000 cm-1), and near-IR spectrum (4000-13000 cm-1). The mid-IR spectrum is the most widely used in the sample analysis, but far- and near-IR spectrum also contribute in providing information about the samples analyzed. The mid-IR spectrum is divided into four regions: •the single bond region (2500-4000 cm-1), •the triple bond region (2000-2500 cm-1), •the double bond region (1500-2000 cm- 1), and •the fingerprint region 600-1500 cm- 1 Steps to interpret FT-IR •Step 1: Identification of number of absorption bands in the entire IR spectrum. If the sample has a simple spectrum (has less than 5 absorption bands, the compounds analyzed are simple organic compounds, small mass molecular weight, or inorganic compounds (such as simple salts). But, if the FTIR spectrum has more than 5 absorption bands, the sample can be a complex molecule.
•Step 2: Identifying single bond area (2500- 4000 cm-1). There are several peaks in this area: A broad absorption band in the range of between 3650 and 3250 cm-1, indicating hydrogen bond. This band confirms the existence of hydrate (H2O), hydroxyl (- OH), ammonium, or amino. For hydroxyl compound, it should be followed by the presence of spectra at frequencies of 1600–1300, 1200–1000 and 800–600 cm-1. However, if there is a sharp intensity absorption in the absorption areas of 3670 and 3550 cm-1, it allows the compound to contain an oxygen- related group, such as alcohol or phenol (illustrates the absence of hydrogen bonding). Steps to interpret FT-IR •Step 3: Identifying the triple bond region (2000-2500 cm-1) For example, if there is a peak at 2200 cm-1, it should be absorption band of C≡C. The peak is usually followed by the presence of additional spectra at frequencies of 1600– 1300, 1200– 1000 and 800–600 cm-1.
•Step 4: Identifying the double bond region (1500-2000 cm-1)
Double bond can be as carbonyl (C = C), imino (C = N), and azo (N = N) groups.
•Step 5: Identifying the fingerprint region (600-1500 cm-1)
This area is typically specific and unique. This region show absorption band of C-F, C-I,C-Br also. RESULT The IR Spectrum of Potassium ferricyanide obtained from FT-IR is successfully analysed. REFERENCES ❑ Nakagawa I, Shimanouchi T. Infrared spectroscopic study on the co- ordination bond-II: Infrared spectra of octahedral metal cyanide complexes. Spectrochimica Acta. 1962;18(1):101-113 ❑ http://dx.doi.org/10.1590/1980-5373-MR-2015-0786 ❑ https://www.researchgate.net/figure/Absorbance-infrared-spectra-of-potassium- ferricyanide-obtained-as-potassium-bromide_fig1_23436451 ❑ https://epgp.inflibnet.ac.in/epgpdata/uploads/epgp_content/S001174BS/P001858/ M030452/ET/1526641296P10_M26_ET.pdf ❑ https://epgp.inflibnet.ac.in/epgpdata/uploads/epgp_content/S000831ME/P001676 /M030244/ET/1525950185Module-2_Unit5_COM-I.pdf ❑ VIBRATIONAL SPECTRA OF CRYSTALLINE POTASSIUM FERRIAND FERROCYANIDE Yu. A. Klyuev Zhurnal Prtkladnoi Spektroskopii, Vol. 3, No. 1, pp. 42-48, 1965 Thanks! CREDITS: This presentation template was created by Slidesgo, including icons by Flaticon,and infographics & images by Freepik.
