1. Lattice symmetry of quartz, α-FePO4 and β-FePO4:
Quartz has a trigonal lattice structure with space group P3121 (group no. 152).
At any temperature below 980K, Iron phosphate exists as α-FePO4, which has a trigonal lattice structure with space group P3121 (group no. 152) where iron, phosphate and oxygen occupy Wyckoff position 3a, 3b and 6c respectively. As the temperature rises up to and above 980K, α-FePO4 exhibits α-β transition and becomes β-FePO4 that shows a distinct lattice and space symmetry from α-FePO4. β-FePO4 has hexagonal lattice structure with space group P6422 (group no. 181), in which iron, phosphate and oxygen occupy Wyckoff position 3d, 3c and 12k respectively.
2. Crystal chemistry and space symmetry of quartz, α- FePO4 and β-FePO4:
In quartz, every silicon atom is connected to four oxygen atoms to form a structure of corner-connected tetrahedral. Similarly in α-FePO4, each iron or phosphate atom is also connected to four oxygen atoms, forming corner-connected FeO4 and PO4 tetrahedra respectively. However, β-FePO4 exhibits totally different chemistry and space symmetry from either quartz or α-FePO4.
According to altervalent substitution effect, quartz and iron phosphate demonstrate very similar crystal structure even though silicon, iron and phosphate are distinct chemical elements.
Fe3+ + P5+ → 2Si¬4+
As seen from the equation above, two silicon ions replace one iron(III) ion and one phosphate(V) ion. The total…
Rubisco exists in four forms. Form I Rubisco is a hexadecamer, which is repeated four times in the basic structural motif, a dimer of large subunits, to form a catalytic core of L8, with small subunits on the top and bottom of this core (L8S8).14–16 Form II Rubisco is a simple dimer of large subunits, ranging from L2-8, sharing 25–30% identity to the L subunits of Form I Rubisco. This structure is similar to the structure of the basic dimer of the Form I Rubisco despite some differences in…
TITLE: QUALITATIVE PHASE IDENTIFICATION & CRYSTAL STRUSTURE ANALYSIS OF ISONICOTINAMIDE POLYMORPHS.
The science of crystallography is important in stability studies and determination of solid state molecule or particles. Isonicotinamide (pyridine -4- carboxamide) is the amide form of isonicotinic acid which exists as different polymorphs. Isonicotinamide finds extensive use in the pharmaceutical industry because of its good anti-tubercular, anti-bacterial, anti-pyretic and…
important concepts on various scales. A proper understanding of the internal structure of the material through the characterization methods has become essential to identify the novel materials for a specific device application. Currently wide range of experimental methods is available to know the mechanical, chemical or electrical properties of the chosen materials. In this work, the prepared samples are studied using various techniques given below.
• Powder X-ray diffraction(PXRD)
Lab 4: Crystal Structure and X-Ray Diffraction of Materials
The purpose of this experiment is to study the relationship between the geometry of a sample and its diffraction patterns through an exploration of reciprocal space. In this experiment, both a single crystal piece of Si with a (004) reflection plane and a Si powder sample are scanned, as well as the peaks the locations of the diffraction peaks on the single crystal. The collected data is then analyzed to determine the…
The CT scanner Depends upon several steps:-
1-The x-ray tube and detector transverse (scan)
2-The radiation beam passes through the object and is attenuated. The intensity of radiation beam from x- ray tube and transmitted beam both are detected by suitable detectors.
3-The transmitted beam and the references beam are both converted into electric signals.
4-These output current signals are then converted
into digital form by analog –to-digital converter.
5-The digital data are…
on May 12, 1910 in Cairo, Egypt to her parents, John and Grace Crowfoot.
Her father was a school inspector who later gained an interest in archeology and became the Director of Jerusalem’s British School of Archaeology.
Dorothy’s fascination with chemistry and crystals started when she was ten on a visit to Sudan to visit her father. While she was there, her parents’ friend let her study and analyze chemicals. When she was fifteen, she received a book by William Henry Bragg (a Nobelist in…
For my topic of a Famous Historical Figure, I chose to do my paper on Dorothy Crowfoot Hodgkins. She is a scientist who discovered, through x-ray crystallography, that you can develop protein crystallography, helped with the advancement of the x-ray crystallography technique which was a key element to studying and understanding the 3 dimensional structures of biomolecules, and she also determined the structure of insulin (Women who changed the world •, 2014).
Dorothy Crowfoot Hodgkin was a…
She made significant advances in x-ray diffraction techniques and adjustments in equipment to produce an extremely fine beam of x-rays. Franklin was the first to extract finer DNA fibres and arrange them into parallel bundles, allowing for her to study the fibres reactions to humid conditions. It can be concluded that without Rosalind Franklin’s high-quality images of DNA structure using crystallography, Wilson and Crick would have had no sufficient evidence for their DNA model. In fact, it was…
project, and almost two billion dollars were put into research. Isabella Karle is a scientist who worked in the field of crystallography, and during the Manhattan Project she worked on plutonium chemistry. With her advances in molecular structures, she has allowed scientists…