Lithium borohydride, LiBH4, crystallizes in an orthorhombic system with four molecules per unit cell. The unit cell dimensions are: a = 6.0 A, b = 4.4 A and c = 7.5 A. The density of crystals is (Li =

Question

Lithium borohydride, LiBH4, crystallizes in an orthorhombic system with four molecules per unit cell. The unit cell dimensions are: a = 6.0 A, b = 4.4 A and c = 7.5 A. The density of crystals is (Li = 7, B = 11, Na = 6 × 10^23)

Prashant Kotian · Accepted Answer

Correct answer: A. M(LiBH4) = 7+11+4 = 22 g/mol. V = 6.0*4.4*7.5 = 198 A^3 = 1.98e-22 cm^3. ρ = 4*22/(6e23*1.98e-22) = 0.74 g/cm^3.

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