9.2 The crystal structures of sometypical ionic compoundsAnswerthe following questions:. The packing style of anions ?The position of cations ?Crystal System (or morepreciselyBravaisLattice)The CN's of anions and cations?Number of atoms in a unit cell ?Structural formula ?Fractionalcoordinatesofanions/cations
9.2 The crystal structures of some typical ionic compounds Answer the following questions: • The packing style of anions ? • The position of cations ? • Crystal System ( or more precisely Bravais Lattice) ? • The CN’s of anions and cations ? • Number of atoms in a unit cell ? • Structural formula ? • Fractional coordinates of anions/cations
9.2.1Binaryioniccompounds(AB)Rocksaltstructure,NaCI typeR./R_~ 0.732-0.414fcc/ccpPacking of anions:Position of cations::OctahedralholesCubicFBravais Lattice:6:6C.N. ofA- & B+:Na:Np in a unit cell: 4:4NaCIStructural motif:0, 1/2, 1/21/2, 1/2, 0; 1/2, 0, 1/2;A: 0, 0, 0;0, 0, 1/2B: 1/2, 1/2, 1/2;1/2, 0, 0;0, 1/2, 0;(0.732-0.414) KCl, KBr, SrS, Rbl, BaTe, SrSe, CaS, KI, SrTeMgO,LiF,CaSe,NaBr,CaTe,MgS,Nal,LiCl,(>0.732)KFSrO,BaO,Rb,RbCl,BaS,CuO,CsF,RbBr,BaSe,NaF(<0.414) MgSe,LiBr, LiF, NiO, CoO
R+ /R ~ 0.732-0.414 A: 0, 0, 0; 1/2, 1/2, 0; 1/2, 0, 1/2; 0, 1/2, 1/2 B: 1/2, 1/2, 1/2; 1/2, 0, 0; 0, 1/2, 0; 0, 0, 1/2 (0.732-0.414) KCl, KBr, SrS, RbI, BaTe, SrSe, CaS, KI, SrTe, MgO, LiF, CaSe, NaBr, CaTe, MgS, NaI, LiCl, (>0.732) KF, SrO, BaO, RbF, RbCl, BaS, CuO, CsF, RbBr, BaSe, NaF, (<0.414) MgSe, LiBr, LiF, NiO, CoO . 9.2.1 Binary ionic compounds (AB) Rocksalt structure， NaCl type • Packing of anions: fcc/ccp • Position of cations: Octahedral holes • Bravais Lattice: Cubic F • C.N. of A- & B+ : 6:6 • NA :NB in a unit cell: 4:4 • Structural motif: NaCl
Example 1: CoOO-OO-2Co+2NaCl-typestructureofCoOIts (1l1) surface are charged, having higher surface energythan othernon-polarsurfaces.However,the charged (lll)surface could be stabilized uponcoordination of counterionsfromionicliquids
Example 1: CoO • NaCl-type structure of CoO. • Its (111) surface are charged, having higher surface energy than other non-polar surfaces. • However, the charged (111) surface could be stabilized upon coordination of counterions from ionic liquids
Control the surface byintroducing electrostaticinteractions!R=1.73R=0.58M=30.00.K2Growth of CoOin the200nmabsence of ionic liquidGrowth of CoO in ionic liquid
Growth of CoO in ionic liquid Growth of CoO in the absence of ionic liquid Control the surface by introducing electrostatic interactions!
β-ZnS（Sphalerite/闪锌矿/立方硫化锌）(R./R_:0.225-0.414)fcc/ccpPacking of anions:Position of cations:Tetrahedral holes (1/2)cubic FBravais lattice:4:4C.N. of A- & B+:Na:Np in a unit cell: 4:4ZnSStructural motif:(0,1/2,1/2)A: (0,0,0);(1/2,1/2,0);(1/2,0,1/2);B: (1/4,1/4,1/4); (3/4,3/4,1/4);(1/4,3/4,3/4)(3/4,1/4,3/4);
b-ZnS (Sphalerite/闪锌矿/立方硫化锌) (R+ /R : 0.225-0.414) A: (0,0,0); (1/2,1/2,0); (1/2,0,1/2); (0,1/2,1/2) B: (1/4,1/4,1/4); (3/4,3/4,1/4); (3/4,1/4,3/4); (1/4,3/4,3/4) • Packing of anions: fcc/ccp • Position of cations: Tetrahedral holes (1/2) • Bravais lattice: cubic F • C.N. of A- & B+ : 4:4 • NA :NB in a unit cell: 4:4 • Structural motif: ZnS