Relationships between the Structural, Vibrational, and Optical Properties of Microporous Cancrinite

Abstract

The crystal-chemical, vibrational, and optical properties of microporous aluminosilicate cancrinite have been investigated by combining electron probe microanalysis, single-crystal X-ray diffraction, infrared (IR) absorption, Raman, UV-Visible absorption, and electron spin resonance spectroscopy. The behavior of the peaks in the IR spectra was also studied during the dehydration of the sample. The analyzed sample has the following unit cell parameters (P63): a = 12.63189(14) Å, c = 5.13601(7) Å. The empirical formula, based on 12(Si + Al), is Na6.47Ca1.23K0.01[Al5.97Si6.03O24] (CO3)1.45(SO4)0.03Cl0.01·2H2O. The Al-Si framework of AB-type is formed by columns of based-shared “cancrinite” (CAN) cages, containing Na and H2O positions located on the 3-fold axis, and channels with CO3 groups, lying in two mutually exclusive and partially occupied positions in the center of the channel, and split Na/Ca cation sites. The revealed characteristics are somewhat different in comparison with the cancrinite structural features previously described in the literature. Studied crystals change color from grayish-pink to blue after X-ray irradiation (104 Gy). The blue color of the irradiated cancrinite is caused by the formation (CO3)−● radicals in the crystals. Combining the results obtained using the selected methods will provide a better understanding of the relationships between the structural, chemical, and optical-physical properties of microporous aluminosilicates.

Highly Efficient Photocatalyst Fabricated from the Chemical Recycling of Iron Waste and Natural Zeolite for Super Dye Degradation

“…Si-OH groups with H-bonding were found to have broadbands at 3620 and 3446 cm −1 . The OH bending mode is responsible for an absorption peak at 1640 cm −1 [27]. The O-Si(Al)-O bond vibrations in tetrahedra (TO 4 ) or aluminum-and silicon-oxygen bridges are responsible for the intensive band at 1040 cm −1 [27].…”

“…The OH bending mode is responsible for an absorption peak at 1640 cm −1 [27]. The O-Si(Al)-O bond vibrations in tetrahedra (TO 4 ) or aluminum-and silicon-oxygen bridges are responsible for the intensive band at 1040 cm −1 [27]. In the region of 700-500 cm -1 , the bands were ascribed to four-or five-membered ring vibrations of TO 4 units and stretching of the inter tetrahedral bonds typical of the ordered crystal structure, respectively [27].…”

“…bands were ascribed to four-or five-membered ring vibrations of TO4 units and stretching of the inter tetrahedral bonds typical of the ordered crystal structure, respectively [27].…”

Combined Use of Non-Invasive and Micro-Invasive Analytical Investigations to Understand the State of Conservation and the Causes of Degradation of I Tesori del Mare (1901) by Plinio Nomellini

“…The hypothesis is supported by the spread production of cotton canvases in Italy at the beginning of the 20 th century [27]. In addition, an in-depth analysis of the spectrum collected from the backside of the canvas of sample n. 2 once again highlighted the presence of characteristic peaks which can be related to cellulose, but also to Lead (II) Basic Carbonate [(PbCO3)2•Pb(OH)2] (Figure 10) [28]. Bands at 1401 and 686 cm −1 identify C=O vibrations in the carbonate ion CO3 2− , which can be attributed to the use of Lead (II) Basic Carbonate.…”

Tinaksite and Tokkoite: X-ray Powder Diffraction, Optical, and Vibrational Properties

“…The region with higher wavenumbers after 1200 cm −1 is not given due to a strong luminescence signal. Spectra are both dominated by intense bands, 1118 cm −1 in tinaksite and 1113 cm −1 in tokkoite, assigned to the stretching vibrations of Si-O [32,33]. The most intense bands in tinaksite and tokkoite are located in the region 600-700 cm −1 .…”