Question

NaCl has a rock salt crystal structure with a unit cell edge length of 0.56 nm. The atomic weights of the Na and Cl are 23 and 35.5 g/mol, respectively, and the Avogadro's number is 6.022 x 10“ formula units/mol. (a) Draw a unit cell to show the crystal structure of the NaCl. (b) What is the coordination number of the atoms in this structure? (c) How many Na atoms and Cl atoms in one unit-cell of such a structure? (d) Calculate the density of the NaCl. (e) Calculate the minimum Cation-to-Anion radius ratio for rock salt structure. (f) Calculate the maximum Cation-to-Anion radius ratio for rock salt structure

Answer 1

Giuon unit cell edge length * 0.56 om At wt of Na : 23 g/mol At wt. of d = 35.5 g/mol Avogadro's Nimbor = 6022 X102° mits/mol. a) Draw cenit cell to show Nadl crystal structure. Nad has face Centered Cubic structure. Blue colowr circles denote alions At 8 comers & ¿ faces of the unit cell. Black colour circles denote Nations. O u vi . At 12 edges X Nations occupy the Octahedral centre of the positions. unit cell. 6) Coordination no. of atoms. Central the no. of atomissions surrounding an alom in a Crystal is cooodination no . 1 By counting the other atomssions to which it is. bounded. One Nation at centred Surrounded by clions nit cell. on The coordination sumber is 6. 0 000 as one Goubtles

[ is one. ] No. of wa atoms is given by : - contribution of a nation at centre of unit cell to it 2 " 12 Nation at edges is . (e ledge is shared by four unit cells) Noi of Nations = 1x1 + 1x12 = 4 weit ions. No. of clatoins is given by. 1.8 comers have s clions, one conor is shared by 8 units cells. - Contribution to limit cell is 1/2 x8 = 1 2. Ę faces have 6 ce-ious one face is shared by 2 unit cells. contribution to lumit cell is Ix6 =3. sino. of cious X8+ x6 = 4 cious.

da] density of Nach, e Noce na - VCANA . n = no of atoms in unit cell. A= atomic wt... Vc = . Volume of unit cell. NA = Avagodio's No. Pims 4018 (23735.5) g/mot (0.56 jom}x 60222X1033 atoms mot 4x (23735.5) 10.5673x6.0222318 3x18 21 gice 221025578 glee 100 evac) = 2.2125618 gle.c. = 2.2196cc As per HomeworkLib Policy only four as to be Solved: Hope you understand. Sorry for the inconvenience...