The thermal and mechanical processing of materials is an important step in ensuring that they have the appropriate physical properties for their intended application. Suppose a metallic element undergoes a phase transit ion in which its crystal structure changes from cubic close-packed to bodycentredcubic. (a) Does it become more or less dense? (b) By what factor does its density change?

The thermal and mechanical processing of materials is an important step in ensuring that they have the appropriate physical properties for their intended application. Suppose a metallic element undergoes a phase transit ion in which its crystal structure changes from cubic close-packed to bodycentredcubic. (a) Does it become more or less dense? (b) By what factor does its density change?

Principles of Modern Chemistry

8th Edition

ISBN:9781305079113

Author:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Publisher:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Chapter22: Inorganic Materials

Section: Chapter Questions

Problem 9P

See similar textbooks

Similar questions

(a) Magnesium (Mg) has a hexagonal close-packed (HCP) crystal structure with the lattice parameter of a = 0.321 nm and c= 0.521 nm and the atomic radius is 0.173 nm. (i) What is the number of atoms per unit cell in HCP structure? (ii) Determine the atomic packing factor of the Mg unit cell. (iii) Is Mg containing an ideal atomic packing factor? You may justify your answer by evaluating the HCP c/a ratio. Subsequently, will slip be harder in Mg compared to the ideal HCP structure? Justify your answer.
Calculate the mass density of diamond assuming that it is a close-packed structure of hard spheres with radii equal to half the carbon–carbon bond length of 154.45 pm. (b) The diamond lattice is in fact based on a face-centred cubic lattice but with two atoms per lattice point, such that the structure consists of two interpenetrating fcc lattices, one with its origin at (0,0,0) and the other with its origin at (1/4,1/4,1/4). The experimentally determined mass density is 3.516 g cm−3: can you explain the difference between this value and that in (a)?
(a) Use the Born–Haber cycle, with data from Appendices D and F, to calculate the lattice energy of LiF.(b) Compare the result of part (a) with the Coulomb energy calculated by using an Li-F separation of 2.014 Å in the LiF crystal, which has the rock-saltstructure.
Titanium carbide, TiC, adopts the rock-salt (NaCl) crystal structure. (i) Draw the unit cell indicating clearly the position of all atoms.(ii) The unit cell parameter for TiC is 0.4329 nm. Calculate the C-Cdistance, the Ti-C bond length and the Ti-Ti distance.
The thermal and mechanical processing of materials isan important step in ensuring that they have the appropriatephysical properties for their intended application. Suppose ametallic element undergoes a phase transition in which itscrystal structure changes from cubic close-packed to bodycentred cubic. (a) Does it become more or less dense? (b) Bywhat factor does its density change?
(a) A hypothetical compound MB2 crystallises in the rutile lattice structure. (i) Draw the lattice structure of the unit cell MB2. (ii) Show by calculation that the stoichiometry of the formula is consistent with the structure. (iii) Determine the coordination number of the MB₂ unit cell.
At room temperature, the edge length of the cubic unit cell in elemental silicon is 5.431 Å, and the density of silicon at the same temperature is 2.328 g cm-3 . Each cubic unit cell contains eight silicon atoms. Using only these facts, perform the following operations.(a) Calculate the volume (in cubic centimeters) of one unit cell.(b) Calculate the mass (in grams) of silicon present in a unit cell.(c) Calculate the mass (in grams) of an atom of silicon.(d) The mass of an atom of silicon is 28.0855 u. Estimate Avogadro’s number to four significant figures.
Polonium is the only element known to crystallize in the simple cubic lattice. (a) What is the distance between nearest neighbor polo- nium atoms if the first-order diffraction of X-rays with A = 1.785 Å from the parallel faces of its unit cells appears at an angle of 20 = 30.96° from these planes? (b) What is the density of polonium in this crystal (in g cm-3)?
Sodium hydride (NaH) crystallizes in the rock-salt structure, with four formula units of NaH per cubic unit cell. A beam of monoenergetic neutrons, selected to have a velocity of 2.639 × 103 ms-1 , is scattered in second order through an angle of 2u= 36.26° by the parallel faces ofthe unit cells of a sodium hydride crystal.(a) Calculate the wavelength of the neutrons.(b) Calculate the edge length of the cubic unit cell.(c) Calculate the distance from the center of an Na+ ion to the center of a neighboring H- ion.(d) If the radius of an Na+ ion is 0.98 Å, what is the radius of an H- ion, assuming the two ions are in contact?
(a) Describe the phenomenon and the cause of phase transitions in polymer systems.(b) Describe the role of entropy in heat-induced phase transitions.
For the shown crystal structure, write down (a) the Bravais lattice and (b) the basis of the primitive unit cell. For this structure a=b= c and a=B=y%3D90°. The green (A) atoms at the vertices; blue (B) atom at the center, pink (C) atoms are the centers of two opposite faces; and brown (D) atoms at the centers of four edges of the unit cell. Note that the a, b and c translation vectors are along the positive x, y and z axes, respectively, as shown. COD
Explain (i) The basis of similarities and differences between metallic and ionic crystals.