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atomic packing factor (APF) or packing fraction is the fraction of volume in a crystal structure that is occupied by atoms. It is dimensionless and always less than unity. For practical purposes, the APF of a crystal structure is determined by assuming that atoms are rigid spheres. For one-component crystals (those that contain only one type of atom), the APF is represented mathematically by where Natoms is the number of atoms in the crystal, Vatom is the volume of an atom, and Vcrystalis the volume occupied by the crystal. It can be proven mathematically that for one-component structures, the most dense arrangement of atoms has an APF of about 0.74. In reality, this number can be higher due to specific intermolecular factors. For multiple-component structures, the APF can exceed 0.74.
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Show that the atomic packing factor for the Bcc crystal structure is 0.68?
In body-centred cubic structure,The no. of atoms per unit cell= 2Volume of 2 atoms (spherical)=2*(4/3)πr3We know the radius of atom in BCC isr = a√34Volume occupied by the atoms per unit cell(v) = 8πa√33 4v == 8πa33√3------- ---------3 4*4*4Volume occupied by the atoms per unit cell(v) =πa3√3----8Volume of the unit cell for a cubic system(V) = a3Atomic packing factor (APF) =(πa3√3/8)--------------a3√3(or) APF =π---------8APF = 0.68Therefore, we can say that 68% volume of the unit cell of BCC is occupied by atoms and remaining 32%volume is vacant.Thus the packing density is 68%.
Which is more efficient body centered cubic or face centered cubic?
They are two of the cubic structures for crystals with atoms linked by ionic or covalent bonds. They are also known as BCC and FCC. Table salt, NaCl, and Silicon, for example, assume a FCC structure. For illustrations, please go to the related link.
Why FCC metals are more ductile than Bcc metals?
FCC has a higher packing efficiency and the slip planes are more closely packed than BCC. Infact BCC has more slip systems than FCC. But they are not as closely packed as FCC. For plastic deformation, we need atleast 5 independent slip systems. Both FCC and BCC have those. But the previously mentioned factor makes FCC more ductile than BCC.
Vanadium at 20c is Bcc and has an atomic radius of 0.143 nm calculate a value of its lattice constant a in nanometers?
For all BCC lattice structures, the Lattice constant (a) can be found by : a = (4r) / sqrt(3)
Calculatethe density of Bcc iron at room temperature from the atomic radius of 1.24A and atomic weight of 55.85gmolAvogadro number 6.02310E-23atomic A110E-8cm?
density = 7 897 kg/m^3 = 7.897 g/cm^3
Atomic packing factor of nacl?
Na Cl has an IPF factor not APF as it is compound and APF refer to atomic packing factor, not ionic packing factor.
What is the atomic packing factor of hcp?
.74
What is packing fraction?
Are you referring to the packing factor in Crystallography? This is the proportion of volume taken up by atoms compared to the total volume. See Wikipedia entry for Atomic Packing Factor
How does Atomic packing factor effect property of crystal?
we can assume the density of material.
How do you calculate density of compounds?
p = n x Mr / Vc x NAwhere n is the atoms/unit cell e.g. fcc packing n = 4 and for bcc packing n = 2Mr is the Atomic Mass in g/molVc is the volume/unit cell cm3 = a3 where a can be found by the radius of the atom and the packing used. e.g in bcc packing it is "a = 4r/1.732" . In Fcc packing it is "a= sin (4r)" or "a = cos (4r)"NA is avorgados constant, = 6.023 x1023
How do you calculate theoretical density of compound?
p = n x Mr / Vc x NAwhere n is the atoms/unit cell e.g. fcc packing n = 4 and for bcc packing n = 2Mr is the atomic mass in g/molVc is the volume/unit cell cm3 = a3 where a can be found by the radius of the atom and the packing used. e.g in bcc packing it is "a = 4r/1.732" . In Fcc packing it is "a= sin (4r)" or "a = cos (4r)"NA is avorgados constant, = 6.023 x1023
Show that the atomic packing factor for the Bcc crystal structure is 0.68?
In body-centred cubic structure,The no. of atoms per unit cell= 2Volume of 2 atoms (spherical)=2*(4/3)πr3We know the radius of atom in BCC isr = a√34Volume occupied by the atoms per unit cell(v) = 8πa√33 4v == 8πa33√3------- ---------3 4*4*4Volume occupied by the atoms per unit cell(v) =πa3√3----8Volume of the unit cell for a cubic system(V) = a3Atomic packing factor (APF) =(πa3√3/8)--------------a3√3(or) APF =π---------8APF = 0.68Therefore, we can say that 68% volume of the unit cell of BCC is occupied by atoms and remaining 32%volume is vacant.Thus the packing density is 68%.
Which is more efficient body centered cubic or face centered cubic?
They are two of the cubic structures for crystals with atoms linked by ionic or covalent bonds. They are also known as BCC and FCC. Table salt, NaCl, and Silicon, for example, assume a FCC structure. For illustrations, please go to the related link.
Why FCC metals are more ductile than Bcc metals?
FCC has a higher packing efficiency and the slip planes are more closely packed than BCC. Infact BCC has more slip systems than FCC. But they are not as closely packed as FCC. For plastic deformation, we need atleast 5 independent slip systems. Both FCC and BCC have those. But the previously mentioned factor makes FCC more ductile than BCC.
Vanadium at 20c is Bcc and has an atomic radius of 0.143 nm calculate a value of its lattice constant a in nanometers?
For all BCC lattice structures, the Lattice constant (a) can be found by : a = (4r) / sqrt(3)
What are the factors affecting the refraction index of material?
atomic packing
What is packing factor in self compacting concrete?
Packing factor: In a simple way it is the ratio between the mass of tightly packed (compacted) to the mass of lossely packed.
