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New lattice parameter and density results have been obtained for alloys in the β‐NiAl and 6‐Ni2Al3 phase fields of the nickel–aluminium system. The lattice parameter of the β‐NiAl phase (CsCl‐type) falls linearly from 2.8870 Å at 50 at.% Ni to 2.8618 Å at 66. at.% Ni, with 2.00 atoms per unit cell. On the other hand, the lattice parameter on the Al‐rich side of NiAl falls linearly from 2.8870 Å to 2.8652 Å, while the number of atoms per unit cell falls from 2.00 to 1.817 by the creation of vacancies in normally nickel sites. The trigonal 6‐Ni2Al3 phase‐structure, which is essentially an extension of cubic β‐NiAl, but with every third plane of nickel atoms perpendicular to the trigonal axis missing, shows a minimum in the a and c spacings at stoichiometric Ni2Al3. Density measurements indicate that the vacancies formed by the missing planes are progressively filled as nickel is added to Ni2Al3, but that a substitutional solid solution is formed on the aluminium‐rich side of stoichiometric Ni2Al3 with aluminium replacing nickel atom by atom. In the NiAl phase, the number of valence electrons increases from 2.28 per unit cell at 61.9 at.% Ni to 3.00 at stoichiometric NiAl, and remains constant at 3.00 as the vacancies form until Ni2Al3 is reached, at which stage the number of vacancies will have reached a maximum when there are only 1.67 atoms per pseudo‐cubic cell. The number of electrons per pseudo‐cubic unit cell then begins to rise and reaches the phase boundary value of 3.12 at 37.6 at.% Ni.

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The polyesterification of adipic acid and butane-l,4-diol by a commercial lipase (Lipozyme IM-20) has been studied using a two-chamber reactor and molecular sieve as a dehydrating agent. The lower oligomeric products were identified and a low-dispersity polyester averaging 20 repeat units was produced.