The ZnO crystallizes in a few forms which are wurtzite, zinc blende and rocksalt as shown in Figure 2.4. The wurtzite structure is the most thermodynamically stable phase under ambient temperature and also very common. The zinc blende ZnO geometry can be stabilized only by growth on cubic lattice substrates and the rocksalt structure (NaCl structure) can be obtained at relatively high pressures using ultrasonic wave velocity measurements of up to 10 GPa. (Morkoc).
It occurs naturally as the mineral zincite, but most zinc oxide is produced synthetically (Marcel). Zinc oxide have an array of nanostructures, such as nanorods, nanotubes, nanorings and nanotetrapods (Varadan et. al).
ZnO is a relatively soft material. Compared to Group III nitrides, the elastic
…show more content…
Commercial zinc oxide shows a measurable but low level of water solubility, 0.005 g/litre. Zinc oxide is amphoteric, that is it reacts with both acids and alkalis. With acid it reacts to form familiar compound such as zinc sulfate. With alkali it forms zincates. Zinc oxide exposed to air absorbs both water vapor and carbon dioxide. This results in the formation of basic zinc carbonate.
Zinc oxide also undergoes solid state reactions (calcination) at moderately elevated temperatures. Under electron microscopic examination, commercial zinc oxide frequently shows groups of particles that are conjoined, rather than loosely agglomerated. Zinc oxide calcines with other oxides such as silica and magnesia.
2.3.5 Potential and emerging applications of zinc oxide
Because of its diverse properties, both chemical and physical, zinc oxide is widely used in numerous areas. Among the various potential applications of ZnO that are applicable in today’s industries ranging from rubber to pharmaceutical, from textiles to agriculture, and from electronics and electrotechnology industries. The use of zinc oxide is not limited to only a certain region or area, but rather it is use
Zirconia has three crystalline forms: monoclinic phase, tetragonal phase and cubic phase. Monoclinic phase exists in zirconia stable up to temperature 1170˚C. Above 1170˚C, the monoclinic phase transforms to tetragonal phase and further transform to cubic phase above 2370˚C. While cooling down below 1070˚C, tetragonal phase becomes unstable and start transformation of monoclinic phase. Thus tetragonal phase is hard to exist at the room temperature.
According to recent statistics, zinc is the third most commonly used nonferrous metal in the United States. This unassuming metal was among the first minerals exploited by Man, used as a decorative material for thousands of years, although it never achieved the fame and notoriety of other metals such as gold or silver. In more recent times, new extraction and processing methods have allowed Man to produce higher-quality zinc than ever before, and to use it in an astonishingly high number of chemical and high-tech applications.
...nding on the type of raw materials used, the conditions of crystallization, zeolite crystallinity degree and the desired composition. After that, the crystallized zeolite is separated using rotary vacuum filters and washed with water. These zeolites then undergo few treatments to convert it into catalytic acitve material. The NaY zeolite is exchanged with ammonium ions to get rid of the sodium ions in an ionic exchange tanks which is then filtered out and sprayed with the exchange solution. The excess salts on the exchanged zeolites are removed by washing it. During hydrothermal treatment of the zeolite, it is partially dealmuninated and stabilized and the sodium ions that remains is moved to exchangeable position. The degree of dealumination and unit size of the product is determine through calcination conditions to obtain the microcrystallize product of zeolite.
If heat is applied to Copper (Ⅱ) sulfate pentahydrate, then the experimental form will be equivalent to the theoretical formula. Important key data that will be needed to achieve the goal of the lab experiments includes the initial mass of hydrated crystal, the final mass of anhydrous crystal, the
This article focuses on the chemical structure of FePO4 between 294K and 1073K of thermodynamic scale, through high accuracy x-ray diffraction experiments. From the relatively lower temperature range, it acquires the chemical arrangement of an α-Quartz trigonal as shown below. However, as temperature steadily rises, there exists a series of minor changes, such as β-Tridymite hexagonal change at 870 °C. Hydrated amorphous FePO4 was synthesized in which a solution of (NH4)2HPO4 and FeSO4·7H2O was irradiated by an ultrasonic wave. Materials prepared are: (1) an amorphous sample prepared by heating
The cotunnite-type phase was claimed by L. Dubrovinsky and co-authors to be the hardest known oxide with the Vickers hardness of 38 GPa and thebulk modulus of 431 GPa (i.e. close to diamond's value of 446 GPa) at atmospheric pressure.However, later studies came to different conclusions with much lower values for both the hardness (7–20 GPa, which makes it softer than common oxides like corundum Al2O3 and rutile TiO2) and bulk modulus (~300 GPa).
of a zwitterion is made possible due to the basic properties of the NH2 group
Concretions are most commonly composed of calcite but sometimes can be composed of iron oxide or iron hydroxide such as goethite. But also concretions can be composed of other minerals ranging from siderite, ankerite, dolomite, pyrite, baryite and gypsum.
A multi ion beam sputtering technique can be used to successfully fabricate ferroelectric lead zirconate titanate (PZT). This technique is very advantageous in that the ion beam current and voltage can be attuned which allows for the control of flux density and energy of sputtered materials. This technique also offers lower operating pressures during deposition, controllable deposition, and outstanding uniformity over larger areas, reproducibility, and localized plasma within an ion source. Ion beam sputtering is an excellent growth technique and been used extensively to deposit oxide films and semiconductors. But this method has been used mostly to deposit single element oxides and not multi element compounds such as ferroelectrics like PZT. This is most likely due to the lack of uniformity, reproducibility and control of stoichiometry with depositing multi elemental compounds.
When the first crystal of KNO3 appear in the solution recrystallization is occurring. KNO3 is a solid and in water it still remains to its texture. Although once heated and forming to its liquid form letting it cool until crystal begin forming soon after equilibrium was reached. The temperatures when the crystals form as the total volume of solution increased is when crystal are first observed which is when the reaction is at
81/125 = 0.648g To calculate how much zinc oxide is produced from 2g of calamine 0.648 is doubled: 0.648 x 2 = 1.296g To calculate how much zinc oxide is produced from 3g of calamine 0.648 is tripled and so on when increasing the mass of calamine. On the next page there is a table of the theoretical conversions for how much zinc oxide is produced from using certain amounts of calamine (1g-9g) Mass Of ZnCO₃ (g) Mass of ZnO Produced (g) 1 0.648 2 1.296 3 1.944 4 2.592 5 3.24 6 3.888 7 4.536 8 5.184 9 5.832 Here is a graph of the results predicted from the table………… This experiment is going to see how much zinc oxide can be obtained from calamine. It shall also show how close to the conversion can be achieved in practice. Hypothesis In a previous experiment where copper carbonate was obtained from malachite the results showed that as the more malachite was used the more product was produced.
1.) Gas Syringe 100cm³ - I chose this as it is easy to measure the
Zinc eugenate may decompose in the presence of water through the release of eugenol, making it weak ...
Zinc is an essential trace element for many living organisms. While this can be said about other essential metals, zinc is unique in its physiochemical properties that give it the ability to interact with donor groups of different ligands, resulting in a broad range of stability constants and diversity of the biological functions and processes that zinc is involved in. It was discovered and recognized as a new metal in the eightieth century, While its biological essentiality was found by Raulin for the growth of Aspergillus niger In 1869 [1]. In 1933 Zinc was found essential for the growth of animals while studying its effect on rats. [2]