The photoelectron spectra of several aryl alkyl selenides have been measured. Several of the spectra show evidence for the existence of two predominant rotamers, one with maximumoverlap and one with minimal overlap. Using the interaction model developed here, we show how steric factors effect rotamer populations and demonstrate that electronic effects determine whether or not different rotamers can be detected by the photoelectron technique.Recently we observed1 that the parent hydrocarbon

A gallophosphate, GagP90360H-HNEt3, has been synthesised and its framework structure has been determined by single crystal X-ray diffraction.

The structure of the microporous gallophosphate, Ga2P2O8(0H)H20-NH4.H2O-O.1 6 PrOH, consists of gallium-centred octahedra and phosphorus-centred tetrahedra as basic building units to form three-dimensional channels with the 8-ring running along the a, b, and c axes in which NH4+ cations are located in pairs.Recently the syntheses of a series of microporous aluminophosphates (A1P04-n) have been reported,1-3 some of which are analogues of the aluminosilicate zeolite molecular sieves. Subsequently a number of aluminophosphate derivatives containing silicon, boron, gallium, and various transition metal atoms were synthesized.-The syntheses and structures of some microporous gallophosphates have also been reported.7-10 Compared to the aluminophosphates, the gallophosphates possess more complicated framework structures, which result from the variety in the co-ordination of the gallium atom. Reported here is the X-ray crystal structure of another member of the gallophosphate family (GaP0,-C,),

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