The continuous and ever expanding development of high-temperature tech-
nology involves the use of high -temperature refractory materials and
one of the most important classes of these is the oxides, i.e.,
compounds of elements with oxygen. Oxides are the oldest refractory
compounds known in technology and this is connected with their high
chemical stability and abundance in nature. In addition to the use of
oxides as raw materials for metallurgical processes, the refractoriness,
chemical stability, and magnetic and other technically important
properties of oxides have been put to use since antiquity. At the
present time the importance of oxides as bases of many materials for new
technology is substantial and is growing rapidly with the development of
processes for the direct conversion of various forms of energy into
electrical energy, the development of nuclear technOlogy, electronics,
semiconductor and dielectric technOlogy, and cosmic technology, where
the refractoriness and chemical stability of oxides are used in
combination with their specific physical properties. Oxides are the
foundation of the so-called oxygen -containing or oxygen refractory
materials, which are fundamental to high-temperature tech- nology.
Oxides are no less important as the bases of practically all structural
ma- terials and rocks. A number of oxides are involved in biological
processes.