(b) Many structures of ionic compounds have been described in terms of close packing of a large anion, X, with a cation, A, occupying tetrahedral or octahedral holes. (1) In a cubic close packed lattice, how many octahedral holes are there per lattice ion? (ii) What is the formula of a compound based upon a cubic close packed lattice in which of the octahedral holes are filled? (ii) State the coordination numbers and geometries of A and X In the crystal lattice in part (b)(ii) above.

(b) Many structures of ionic compounds have been described in terms of close packing of a large anion, X, with a cation, A, occupying tetrahedral or octahedral holes. (1) In a cubic close packed lattice, how many octahedral holes are there per lattice ion? (ii) What is the formula of a compound based upon a cubic close packed lattice in which of the octahedral holes are filled? (ii) State the coordination numbers and geometries of A and X In the crystal lattice in part (b)(ii) above.

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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(ii) Prove that the volume of an FCC unit cell, VC is; ?? = 16?3√2
A certain compound, whose density is 4.56 g/cm³, crystallizes in the tetragonal system with unit lattice dimensions of a = b = 6.58 Å and c = 5.93 Ả. If the unit lattice contains four molecules, calculate the molar mass of the compound in g mol"
What is the packing factor if the radius of Ga is 0.62 Å and of As is 1.51 Å? (A) 0.74. (B) 0.68. (C) 0.34. (D) 0.5.
A unit cell has a=5Å, b=5Å, c-8Å, a=90°, B-90° ad y=90°. What will be the Bravais lattice for this unit cell? Mention the following for each of the given crystallographic cubic planes. (a) Intercepts in the x, y and z coordinates (b) Reciprocals (c) Final index of the crystal plane 1/2
The angle of diffraction of (220) set of planes for an FCC element occurs at 69.22° when monochromatic x-radiation having a wavelength of 0.1542 nm is used. (a) Calculate the atomic radius of the element; (b) Calculate the angle of diffraction from the set of planes (310).
6. A compound consists of A-atoms and B-atoms, and its solid crystal forms a cubic unit cell structure, as shown below. A-atoms occupy corners and faces of the cube. B-atoms are inside the cube and are not shared by adjacent cubic unit cells. Based on the information here, we can conclude that (a) A-atoms form an FCC structure; the empirical formula of the compound is A,B2. (b) A-atoms form an FCC structure; the empirical formula of the compound is AB. (c) A-atoms form a BCC structure; the empirical formula of the compound is A¬B2. (d) A-atoms form a BCC structure; the empirical formula of the compound is AB. (e) None of the above. A-atoms (corners and faces) B-atoms (inside, not shared) a m n T OF THE FL EMENTS
(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.
(a) The unit cells of three structural types of ionic solids are shown below (the anions appear light and the cations dark). The anions occupy the lattice positions. X (B) (A) (i) Name the common structural type for (A), (B) and (C). (Hint: a typical structural type is rutile (T1O₂).] (C) (ii) The structures (A), (B) and (C) can be considered as packing of anlons with the cations occupying specific types of hole. For each structure: state the unit cell that the packing of anions is based on. state which holes are occupied by the cations and what fraction of them are occupied. State the coordination numbers of the cations and anions for (A), (B) and (C).
(c) State any assumptions that are made regarding close packing of atoms in crystalline solids compared to covalent bonding. (d) Draw the unit cell for a body-centered cubic (BCC) unit cell. Identify ALL contributions to the overall atom count.
(e) The group IV elements also exhibit allotropy. (i) What is allotropy? (ii) Give two crystalline forms of each of the following group IV elements: Carbon isi Tin