Question

7. Identify the essential symmetry element(s) for the following: orthorhombic (i), tetragonal (ii) and cubic (iii) unit cells below. (iii)

Answer 1

The unit cell is the simplest repeating unit in the crystal ,

Opposite faces of a unit cell are parallel ,

The edge of the unit cell connects equivalent points .

These unit cells fall into seven categories which differ in three unit cell edge lengths(a,b&c) and three internal angles ($\alpha \beta \gamma$).

The detailed answer is given in the images below.
teroal Edge leuihs (=BT-90) (a-b-c) Cubic Tehragonal (a btc) Monocinic Oxthoxhombie (at64c) (at640) Khom bo hedral (a 6- c) (abtc) (=-90,7120) (Yoma) Poi clinic Catbtc) Ac Elements the E, 3 , 36 Orthorhombic 1THxaganal , Cu, uc, (lau to Cu), 26y g d 2 Dh Dyh h, S(Coinidnt with Cu)

Element ont gleup Th KM) Cubic uvit cell Caincident with C

Hope it will help.

Thank you.