Problem1 (10 points): Atomic radi valence are given in the following table for s
ID: 1767264 • Letter: P
Question
Problem1 (10 points): Atomic radi valence are given in the following table for several elements, for atomic radii are indicated. us, crystal structure, electronegativity, and the most common those that are nonmetals, only Atomic Radius Element Crystal Structure FCC Electronegativit (nm) 0.1246 0.071 0.046 0.060 0.1445 0.1431 0.1253 0.1249 0.1241 0.1387 0.1332 Ni Valence 1.8 +2 Ag Al Co FCC FCC HCP BCC FCC HCP 1.4 1.5 1.7 1.6 1.7 1.5 +2 +3 +2 +2 Pt Zn 1.7 +2 Which of these elements would you expect to form the following with nickel (f necessary, please choose more than one elements): (a) A substitutional solid solution having complete solubility 0b A substiutonal solid solution of icompe solablly (c) An interstitial solid solutionExplanation / Answer
Solution
In this problem we are asked to which all the elements listed form with Ni the three possible Solid Solutions types.
For solubility of the following criteria must be:
1. the difference in atomic radii between Ni and other element must be less than +15%,
2. The crystals structures must be same,
3. The electronegativities must be similar,
4.The valences should be the same, or nearly the same.
Element delta R% crystal structures Electronegativity Valence
Ni FCC 2+
C -43
H -63
O -52
AG +16 FCC +0.1 1+
AL +15 FCC -0.3 3+
CO +0.6 HCP 0 2+
Cr +0.2 BCC -0.2 3+
Fe -0.4 BCC 0 2+
Pt +11 FCC +0.4 2+
Zn +7 HCP -0.2 2+
a) Pt is the only element that meets all of the criteria and thus forms a substitutional solid solutions having complete solubility. At elevated temmperatures Co and Fe experience allotropic transformations to the FCC crystal structure, and thus display complete solid solubility at these temperatures.
b) Ag,Al,Co,Cr,Fe and Zn form substitutional solid solutions of incomplete solubility. All these metals have either BCC or HCP crystal structures, and /or the difference between their atomic radii and that for Ni are greater than +15%, and /or jave a valence difference than 2+.
c) C,H,O form interstitial solid solutions. These elements have atomic radii that are significantly smaller than the atomic radius of Ni.
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