The radius ratios of the ions in ionic lattiaces helps predict coordination numb
ID: 956014 • Letter: T
Question
The radius ratios of the ions in ionic lattiaces helps predict coordination number of the cation. This in turn, in combination with the stoiciometry, helps one to predict the lattice type. For each of the following, predict the lattice type of the resulting salt.
________ 1Li(s) + Cl2(g) --> _______ _______(s). The radius ratio (to two decimals) is _______. The predicted coordination number of the smaller ion is _______. The predicted lattice types is _______.
_______Na(s) + Te(g) --> _______ _______(s). The radius ratio (to two decimals) is _______. The predicted coordination number of the smaller ion is _______. The predicted lattice types is _______.
2Tl(s) + Cl2(g) --> 2_______(s). The radius ratio (to two decimals) is _______. The predicted coordination number of the smaller ion is _______. The predicted lattice types is_______.
Am(s) + O2(g) --> AmO2(s). The radius ratio (to two decimals, r+(Am) = 200 pm) is _______. The predicted coordination number of the smaller ion is _______. The predicted lattice types is _______.
Explanation / Answer
Radius ratio = r+ / r-
1. 2Li(s) + Cl2(g) ----------> 2LiCl
Radius ratio = r+ / r- = Li+ / Cl- = 0.076 nm / 0.181 nm = 0.42
The radius ratio (to two decimals) is 0.42. The predicted coordination number of the smaller ion is 6. The predicted lattice types is octahedral.
2. 2Na(s) + Te(g) ---------> Na2Te (sodium telluride)
Radius ratio = r+ / r- = Na+ / Te2- = 0.102nm / 0.221 nm = 0.46
The radius ratio (to two decimals) is 0.46. The predicted coordination number of the smaller ion is 6. The predicted lattice types is octahedral.
3. 2Tl(s) + 3Cl2(g) --> 2TlCl3
Radius ratio = r+ / r- = Tl3+ / Cl- = 0.0885nm / 0.181 nm = 0.49
The radius ratio (to two decimals) is 0.49. The predicted coordination number of the smaller ion is 6. The predicted lattice types is octahedral.
4. Am(s) + O2(g) --> AmO2(s)
Radius ratio = r+ / r- = Am+4 / O2- = 0.2 nm / 0.14 nm = 1.43
The radius ratio (to two decimals) is 1.43. The predicted coordination number of the smaller ion is 12. The predicted lattice types is cuboctahedron (Oh).