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With new X-ray data from a crystal of stoichiometric K0.33MoO3 the crystal structure of this compound was refined until R(anisotropic) = 0.023. The characteristic distortion of the Mo-O octahedra is discussed.
The two-electron reduction of tetraphenyl-p-quinodimethane M via its radical anion M⊖ to its dianion M⊖⊖ is explored both by cyclovoltammetry and ESR/ENDOR spectroscopy. Contact of the diglyme solution with added 15-crown-5 under aprotic conditions with a sodium metal mirror yields black crystals of a solvent-separated contact ion triple [M⊖⊖][Na⊕(OCH2CH2)5(H3CO(CH2CH2O)2CH3)]2. The two-electron-insertion into the pquinodimethane derivative R2C⊖=C(HC=CH)2C=CR2 changes its structure drastically to that of a twofold carbanion substituted benzene, R2C⊖ -(C6H4)- ⊖CR2. MNDO calculations provide a rationale for both the tremendous solvation of a Na⊕ center coordinated to seven oxygen centers of 15-crown-5 and of one diglyme molecule and the structural changes as well as the charge distribution in the unique Tetraphenyl-p-quinodimethane dianion (H5C6)2C⊖-(C6H4)- ⊖C(C6H5)2, in which the two negative charges are largely localized at the carbanion center of the benzene -substituents.
Li6UO6 has a reversible phase transformation at 680°C and decomposes above about 850°C. At high pressure the low temperature modification becomes unstable because of an invariant point in the system Li2O—Li4UO5 at approximately 13 Kb and 620°C. β-Li6UO6 has a triclinic unit cell with a = 5.203, b= 5.520, c = 5.536 Å, α = 114.7, β = 120.7 and γ = 75.5°. The close relationship between the crystal structures of Li6TeO6 and Li6UO6 is also suggested from similar infrared spectra and from partial solid solution Li6UO6—Li6TeO6.