Polymorphisms of Crystalline Solids
Polymorphism is the phenomenon where a compound can precipitate to form numerous crystal structures. Due to space and time limitations, we have decided to confine the scope of this paper to only include polymorphisms of crystalline solids and not include polymorphisms associated with DNA and genetic related topics. It is important in many areas of technology, that people are aware of the presence of polymorphisms and the properties of the different polymorphisms. The different crystalline structures each have different physical properties, which can change the use of the chemical. The physical properties that may differ from one polymorphism to another include: solubility, density, melting point and even color. One of the variables that affect the crystallization process is the solvent that is used in the precipitation. The solvent may cause less stable polymorphisms to form instead of those that are more stable. Predictions can be made as to which polymorphism will be formed based on the solvent and its properties. The mixing conditions also have an affect on the formation of various polymorphisms. (Meyerson) Different polymorphisms can also be formed by manipulating the solute concentrations, flows rates, and equipment configurations. Research involving polymorphisms is becoming increasingly important to the pharmaceutical industry due to the number of pharmaceuticals that are prone to polymorphisms, patents on certain polymorphisms, the differing bioavailability of the polymorphisms and the differing effects of the polymorphisms on the body. (Meyerson)
During the 1970’s, G.M.J. Schmidt coined the term crystal engineering and defined it as predicting the crystal structure of solid-state organic molecules (Sharma). In 1989, G.R. Desiraju revised the meaning as the “ ‘the understanding of intermolecular interactions in the context of crystal packing and in the legalization of such understanding and the design of new solids with desired physical and chemical properties’ ” (Sharma). Crystal engineering has grown to encompass the study of the hardness and color of solids, nanotechnology, protein receptor binding, pharmaceutical development, and polymorphisms (Sharma).
Crystals are used in many areas of science, pharmaceuticals, and materials engineering. Crystals differ from many other organic and inorganic materials because of their ability to form polymorphisms.
Although he was rash, untutored in the ways of the backcountry, and incautious to the point of foolhardiness, he wasn’t incompetent-he wouldn’t have lasted 113 days if he were and he wasn’t a nutcase...McCandless was pilgrim, perhaps”(84). Because McCandless was a believer during the whole duration to his destination, when he died he was at peace with himself and the life that he was given the privilege to live. He no longer was worrying about his father’s betrayal ways, and his mother’s childlike mind. McCandless got what he asked for, and that was to live and to die alone after achieving his dream. Before Chris was at his final ends of life, he took his last breaths to thank god and send everyone his blessings(199). Chris McCandless was born to be an overachiever and died taking pride in who he knew he was and what he had done. He’s more than just a hitchhiker, he’s a
Craig, D. Q. (2002). Pharmaceutical Applications of Micro-Thermal Analysis. Journal of Pharmaceutical Science, 91(5), 1201-1213.
Throughout McCandless’s adventure in the Alaskan wild, he made a series of choices. His survival was made possible by his ability to adapt to harsh conditions. The fact that he survived all his ventures and hardships might have been due more to good fortune than his actual preparation and skills. It is theorized that it was his point to make the Alaska trip so difficult, and so barebones, that he wasn’t sure whether he would have been able to survive it or not. This journey, though reckless, makes his adventure into the Alaskan wild that much more admirable. For Chris to live a life with little to no material objects and survive on his own, in itself, is an act of extreme bravery and determination. Some may say that the
Lovgren, Stefan. Can Art Make Nanotechnology Easier t Understand? 23 December 2003. Web. 3 May 2014. .
Chris McCandless was a young man who attempted to escape the firm grasp of society, and to do so he embarked on unaccompanied hike into the Alaskan wilderness. In the novel Into the Wild written by Jon Krakauer, the author narrates Chris’s excursion into solitude, and the effects of his actions. Chris McCandless is mostly responsible for his death in the Alaskan wilderness.
However when he was seeking his purpose it really didn't register that there are consequences for acting reckless. Though being reckless was a way for him to truly experience the wilderness in a manner that he lived on the edge, “ He didn't think the odds applied to him. We were always trying to pull him back from the edge.” McCandless being outlandish from most of his age group that lead to McCandless trying to find the reason why is the world how it is, “ Chris marches to a different drummer.” Though in the wilderness he found that this world is still beautiful we just have to take a step back and enjoy to the
Chris McCandless was an ordinary person before he decided to make a decision that would in the end change his life drastically, people ask was he an idiot or not? I believe he was more onto the idiot side. He went to one of the best colleges in the united states and would make quite a bit of money. But no he made the decision to go into the wild. Untrained and weak he went off into the wild, no care in the world. He lasted 112 days and died of starvation but on his way he ate a poisonous plant which made him very sick, this is why when you go off into the wild you should know what your plan is and how you're going to accomplish your task/goal.
Chris McCandless was a “real gung ho,” said Jim Gallien, one of the characters in the book who was the last person to see Chris alive. Chris set high standards for himself, and was hired by a various amount of people throughout his journey. All of the employers have quoted him to be a hard worker, and reliable. Wayne Westerberg
The story of Christopher McCandless is that of an over-ambitious youth trying to find himself. Chris’ story, as told in detail in Into the Wild by Jon Krakauer, ended tragically in his death within the Alaskan wilderness many months after running away from home with no contact to his family. In Krakauer’s work, he recounts interactions between Chris during his travels and multiple strangers. In this, one may conclude that Christopher McCandless is simply a reckless narcissist, who is selfish and privileged enough to think he can do and get away with whatever he wants. This is, in an emotional analysis, incorrect. Chris was subject to a severe Icarus complex, his ambitions being more than his body and life can handle. He refuses to contact his
Mixed melting point was used to confirm the identity of the product. The smaller the range, the more pure the substance. When the two substances are mixed; the melting point should be the same melting range as the as the melting range obtained after filtering. If the mixed melting point is lower one taken from the crystals, then the two substances are different.
BACKGROUND Types of Silica Crystalline silica may be of several distinct types. Quartz, a form of silica and the most common mineral in the earth's crust, is associated with many types of rock. Other types of silica include cristobalite and tridymite. Potential for Exposure During Construction Concrete and masonry products contain silica, sand and rock containing silica. Since these products are primary materials for construction, construction workers may be easily exposed to respirable crystalline silica during activities such as the following: Chipping, hammering, and drilling of rock Crushing, loading, hauling, and dumping of rock   high dust concentrations.
The unique set of elements known as the alkaline earth metals are key components to humanity and life as we know it. Without them, many things that we both love and need would be gone. These remarkably diverse yet very similar elements that make up the alkaline earth metals family are: Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). Although this family is often overshadowed by the infamous alkali metals, you will soon learn how spectacular and brilliant these metals really are and their value to human life.
Metalloids are elements that share properties of both nonmetals and metals. They usually share physical properties with metals and chemical properties with nonmetals. Although they are not as good at conducting electricity and heat as metals, metalloids can still act as semiconductors; they can act as conductors in the right condition. Metalloids are solid at room temperature and are semiconductive. Being semiconductive means that, in the right conditions, metalloids can conduct heat and electricity. Because of their metallic physical properties, metalloids most commonly appear to be lustrous and brittle. Metalloids’ nonmetallic chemical properties allow metalloids to form alloys with metals and be weakly acidic. Metal-metalloid alloys such as pewter and Babbitt can be used in porcelain and electrical motors alongside other uses.
Raman and IR spectral studies is an important area in the field of lattice dynamics as it contains rich and valuable information. It gives the information about the structure and chemical composition of the compound. Raman and infrared spectra is used in the identification of the molecule. This data is also helpful in determining the site symmetry occupied by the atom and its exact position within a crystal. Many inorganic complex structured compounds change their structural phase at particular physical conditions. These transitions in the compound from one phase to the other can be determined through the Raman and infrared spectral data. Using this, vibrational frequencies of the compounds can also be identified and assigned on the basis of normal coordinate analysis.
Ionic compounds, when in the solid state, can be described as ionic lattices whose shapes are dictated by the need to place oppositely charged ions close to each other and similarly charged ions as far apart as possible. Though there is some structural diversity in ionic compounds, covalent compounds present us with a world of structural possibilities. From simple linear molecules like H2 to complex chains of atoms like butane (CH3CH2CH2CH3), covalent molecules can take on many shapes. To help decide which shape a polyatomic molecule might prefer we will use Valence Shell Electron Pair Repulsion theory (VSEPR). VSEPR states that electrons like to stay as far away from one another as possible to provide the lowest energy (i.e. most stable) structure for any bonding arrangement. In this way, VSEPR is a powerful tool for predicting the geometries of covalent molecules.