Encyclopedia of Crystallographic Prototypes

AFLOW Prototype: A5B3_oP16_26_a2c_a2b-001

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H. Eckert, S. Divilov, M. J. Mehl, D. Hicks, A. C. Zettel, M. Esters. X. Campilongo and S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 4. Submitted to Computational Materials Science.

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Metastable Au$_{5}$Zn$_{3}$ Structure: A5B3_oP16_26_a2c_a2b-001

Picture of Structure; Click for Big Picture
Prototype Au$_{5}$Zn$_{3}$
AFLOW prototype label A5B3_oP16_26_a2c_a2b-001
ICSD 58629
Pearson symbol oP16
Space group number 26
Space group symbol $Pmc2_1$
AFLOW prototype command aflow --proto=A5B3_oP16_26_a2c_a2b-001
--params=$a, \allowbreak b/a, \allowbreak c/a, \allowbreak y_{1}, \allowbreak z_{1}, \allowbreak y_{2}, \allowbreak z_{2}, \allowbreak y_{3}, \allowbreak z_{3}, \allowbreak y_{4}, \allowbreak z_{4}, \allowbreak x_{5}, \allowbreak y_{5}, \allowbreak z_{5}, \allowbreak x_{6}, \allowbreak y_{6}, \allowbreak z_{6}$

  • (Iwasaki, 1965) found this structure to form metastably between 300° and 600°. Below 300° it transforms into the ordered Au$_{5}$Zn$_{3}$ structure.
  • There is considerable disorder on most of the sites in this system, to wit:
    • Site Au-I (2a) is 60% gold and 40 % zinc,
    • Site Zn-I (2c) is 20% gold and 80 % zinc,
    • Site Zn-II (2b) is 10% gold and 90 % zinc,
    • Site Zn-III (2b) is 40% gold and 60 % zinc,
    • Site Au-II (4c) is 85% gold and 15 % zinc, and
    • Site Au-III (4c) is 100% gold with no zinc.
  • We label each site by its dominant component.
  • (Iwaskai, 1965) gave the lattice constants in kX units. We used the conversion factor 1 kX = 1.00202Å. (Wood, 1947).
  • The ICSD entry is from (Iwasaki, 1962).

\[ \begin{array}{ccc} \mathbf{a_{1}}&=&a \,\mathbf{\hat{x}}\\\mathbf{a_{2}}&=&b \,\mathbf{\hat{y}}\\\mathbf{a_{3}}&=&c \,\mathbf{\hat{z}} \end{array}\]

Basis vectors

Lattice coordinates Cartesian coordinates Wyckoff position Atom type
$\mathbf{B_{1}}$ = $y_{1} \, \mathbf{a}_{2}+z_{1} \, \mathbf{a}_{3}$ = $b y_{1} \,\mathbf{\hat{y}}+c z_{1} \,\mathbf{\hat{z}}$ (2a) Au I
$\mathbf{B_{2}}$ = $- y_{1} \, \mathbf{a}_{2}+\left(z_{1} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ = $- b y_{1} \,\mathbf{\hat{y}}+c \left(z_{1} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ (2a) Au I
$\mathbf{B_{3}}$ = $y_{2} \, \mathbf{a}_{2}+z_{2} \, \mathbf{a}_{3}$ = $b y_{2} \,\mathbf{\hat{y}}+c z_{2} \,\mathbf{\hat{z}}$ (2a) Zn I
$\mathbf{B_{4}}$ = $- y_{2} \, \mathbf{a}_{2}+\left(z_{2} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ = $- b y_{2} \,\mathbf{\hat{y}}+c \left(z_{2} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ (2a) Zn I
$\mathbf{B_{5}}$ = $\frac{1}{2} \, \mathbf{a}_{1}+y_{3} \, \mathbf{a}_{2}+z_{3} \, \mathbf{a}_{3}$ = $\frac{1}{2}a \,\mathbf{\hat{x}}+b y_{3} \,\mathbf{\hat{y}}+c z_{3} \,\mathbf{\hat{z}}$ (2b) Zn II
$\mathbf{B_{6}}$ = $\frac{1}{2} \, \mathbf{a}_{1}- y_{3} \, \mathbf{a}_{2}+\left(z_{3} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ = $\frac{1}{2}a \,\mathbf{\hat{x}}- b y_{3} \,\mathbf{\hat{y}}+c \left(z_{3} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ (2b) Zn II
$\mathbf{B_{7}}$ = $\frac{1}{2} \, \mathbf{a}_{1}+y_{4} \, \mathbf{a}_{2}+z_{4} \, \mathbf{a}_{3}$ = $\frac{1}{2}a \,\mathbf{\hat{x}}+b y_{4} \,\mathbf{\hat{y}}+c z_{4} \,\mathbf{\hat{z}}$ (2b) Zn III
$\mathbf{B_{8}}$ = $\frac{1}{2} \, \mathbf{a}_{1}- y_{4} \, \mathbf{a}_{2}+\left(z_{4} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ = $\frac{1}{2}a \,\mathbf{\hat{x}}- b y_{4} \,\mathbf{\hat{y}}+c \left(z_{4} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ (2b) Zn III
$\mathbf{B_{9}}$ = $x_{5} \, \mathbf{a}_{1}+y_{5} \, \mathbf{a}_{2}+z_{5} \, \mathbf{a}_{3}$ = $a x_{5} \,\mathbf{\hat{x}}+b y_{5} \,\mathbf{\hat{y}}+c z_{5} \,\mathbf{\hat{z}}$ (4c) Au II
$\mathbf{B_{10}}$ = $- x_{5} \, \mathbf{a}_{1}- y_{5} \, \mathbf{a}_{2}+\left(z_{5} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ = $- a x_{5} \,\mathbf{\hat{x}}- b y_{5} \,\mathbf{\hat{y}}+c \left(z_{5} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ (4c) Au II
$\mathbf{B_{11}}$ = $x_{5} \, \mathbf{a}_{1}- y_{5} \, \mathbf{a}_{2}+\left(z_{5} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ = $a x_{5} \,\mathbf{\hat{x}}- b y_{5} \,\mathbf{\hat{y}}+c \left(z_{5} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ (4c) Au II
$\mathbf{B_{12}}$ = $- x_{5} \, \mathbf{a}_{1}+y_{5} \, \mathbf{a}_{2}+z_{5} \, \mathbf{a}_{3}$ = $- a x_{5} \,\mathbf{\hat{x}}+b y_{5} \,\mathbf{\hat{y}}+c z_{5} \,\mathbf{\hat{z}}$ (4c) Au II
$\mathbf{B_{13}}$ = $x_{6} \, \mathbf{a}_{1}+y_{6} \, \mathbf{a}_{2}+z_{6} \, \mathbf{a}_{3}$ = $a x_{6} \,\mathbf{\hat{x}}+b y_{6} \,\mathbf{\hat{y}}+c z_{6} \,\mathbf{\hat{z}}$ (4c) Au III
$\mathbf{B_{14}}$ = $- x_{6} \, \mathbf{a}_{1}- y_{6} \, \mathbf{a}_{2}+\left(z_{6} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ = $- a x_{6} \,\mathbf{\hat{x}}- b y_{6} \,\mathbf{\hat{y}}+c \left(z_{6} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ (4c) Au III
$\mathbf{B_{15}}$ = $x_{6} \, \mathbf{a}_{1}- y_{6} \, \mathbf{a}_{2}+\left(z_{6} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ = $a x_{6} \,\mathbf{\hat{x}}- b y_{6} \,\mathbf{\hat{y}}+c \left(z_{6} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ (4c) Au III
$\mathbf{B_{16}}$ = $- x_{6} \, \mathbf{a}_{1}+y_{6} \, \mathbf{a}_{2}+z_{6} \, \mathbf{a}_{3}$ = $- a x_{6} \,\mathbf{\hat{x}}+b y_{6} \,\mathbf{\hat{y}}+c z_{6} \,\mathbf{\hat{z}}$ (4c) Au III

References

  • H. Iwasaki, The Crystal Structure and the Phase Transition of a Metastable Phase in the Au-37.8% Zn Alloy, J. Phys. Soc. Jpn. 20, 2129–2140 (1965), doi:10.1143/JPSJ.20.2129.
  • E. A. Wood, The Conversion Factor for kX Units to Angström Units, J. Appl. Phys. 18, 929–930 (1947), doi:10.1063/1.1697570.
  • H. Iwasaki, Study on the Ordered Phases with Long Period in the Gold-Zinc Alloy System II. Structure Analysis of Au$_{3}$Zn[R$_{1}$], Au$_{3}$Zn[R$_{2}$] and Au$_{3}+$Zn, J. Phys. Soc. Jpn. 17, 1620–1633 (1962), doi:10.1143/JPSJ.17.1620.

Prototype Generator

aflow --proto=A5B3_oP16_26_a2c_a2b --params=$a,b/a,c/a,y_{1},z_{1},y_{2},z_{2},y_{3},z_{3},y_{4},z_{4},x_{5},y_{5},z_{5},x_{6},y_{6},z_{6}$

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