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A new, completely automated gas chromatography technique has been developed to separate the different gaseous compounds produced during underground coal gasification for their 13C/12C and D/H isotope ratio measurements. The technique was designed for separation and collection of [H.sub.2], CO, C[O.sub.2], [H.sub.2]O, [H.sub.2]S, C[H.sub.4], and heavier hydrocarbons. These gaseous compounds are perfectly separated by the gas-phase chromatograph and quantitatively sent to seven combustion and collection lines. [H.sub.2], CO, C[H.sub.4], and heavier hydrocarbons are quantitatively oxidized to C[O.sub.2] and/or [H.sub.2]O. The isotopic analyses are performed by the sealed-tube method. The zinc method is used for reduction of both water and [H.sub.2]S to hydrogen for D/H analysis. Including all preparation steps, the reproducibility of isotope abundance values, for a quantity higher than or equal to 0.1 mL of individual components in a mixture (5 mL of gases being initially injected in the gas chromatograph), is [+ or -]0.1[per thousand] for [Delta]13[C.sub.PDB] and [+ or -]6[per thousand] for [Delta][D.sub.SMOW].

Several compounds of the (Na1−xLix)CdIn2(PO4)3 solid solution were synthesized by a solid-state reaction in air, and pure alluaudite-like compounds were obtained for x=0.00, 0.25, and 0.50. X-ray Rietveld refinements indicate the occurrence of Cd2+ in the M(1) site, and of In3+ in the M(2) site of the alluaudite structure. This non-disordered cationic distribution is confirmed by the sharpness of the infrared absorption bands. The distribution of Na+ and Li+ on the A(1) and A(2)′ crystallographic sites cannot be accurately assessed by the Rietvled method, probably because the electronic densities involved in the Na+→Li+ substitution are very small. A comparison with the synthetic alluaudite-like compounds, (Na1−xLix)MnFe2(PO4)3, indicates the influence of the cations occupying the M(1) and M(2) sites on the coordination polyhedra morphologies of the A(1) and A(2)′ crystallographic sites. [Copyright &y& Elsevier]