  An earlier analysis of manganese oxides in various charge states indicated
that free-atom term values and universal coupling gave a reasonable account of
the cohesion. This approach is here extended to LaxSr(1-x)MnO3 in a perovskite
structure, and a wide range of properties, with comparable success, including
the cohesion, as a function of x. Magnetic and electronic properties are
treated in terms of the same parameters and the cluster orbitals used for
cohesion. This includes an estimate of the Neel and Curie-Weiss temperatures
for SrMnO3, an antiferromagnetic insulator, and the magnitude of a Jahn-Teller
distortion in LaMnO3 which makes it also insulating with (100) ferromagnetic
planes (due to a novel double-exchange for the distorted state),
antiferromagnetically stacked, as observed. We estimate the Neel temperature
and its volume dependence, and the ferromagnetic Curie-Weiss temperature which
applies between the Neel and Jahn-Teller temperatures. We expect hopping
conductivity when there is doping (0<x<1) and estimate it in the context of
small-polaron theory. It is in accord with experiment between the Neel and
Jahn-Teller temperatures, but below the Neel temperature the conduction appears
to be band-like, for which we estimate a hole mass as enhanced in large-polaron
theory. We see that above the Jahn-Teller temperature LaMnO3 should be metallic
as observed, and paramagnetic with a ferromagnetic Curie-Weiss constant which
we estimate. Many of these predictions are not so accurate, but are
sufficiently close to provide a clear understanding of all of these properties
in terms of a simple theory and parameters known at the outset. We provide also
these parameters for Fe, Co, and Ca so that formulae for the properties can
readily be evaluated for similar systems.
