The Solid State

A semiconductor, any of a class of crystalline solids intermediate in electrical conductivity between a conductor and an insulator.

Graphite is an electrical conductor, not a semiconductor. The C atoms in graphite are arranged in parallel planes with hexagons in the planes (strong bond - sp² hybridization), and a pi (weak) bond between the planes. This pi bond gives the free electons for electrical conduction for graphite.

A semiconductor, any of a class of crystalline solids intermediate in electrical conductivity between a conductor and an insulator.

Graphite is an electrical conductor, not a semiconductor. The C atoms in graphite are arranged in parallel planes with hexagons in the planes (strong bond - sp² hybridization), and a pi (weak) bond between the planes. This pi bond gives the free electons for electrical conduction for graphite.

Formula: MₓY₂O₄.
M exists as M²⁺ and M³⁺, Y is +3.
Fraction of M²⁺ = 1/3.

Total M per formula = x.
M²⁺ ions = (1/3)x → charge = 2·(1/3)x = (2/3)x.
M³⁺ ions = (2/3)x → charge = 3·(2/3)x = 2x.
Y³⁺ ions = 2 → charge = 2·3 = 6.
O²⁻ ions = 4 → charge = 4·(−2) = −8.

Charge neutrality: (2/3)x + 2x + 6 − 8 = 0
⇒ (8/3)x − 2 = 0 ⇒ (8/3)x = 2 ⇒ x = 6/8 = 0.75.