On Quadratic Malcev Algebra

A Malcev algebra admits a nondegenerate invariant symmetric bilinear form, i.e., quadratic Malcev algebra is examined in this paper. Quadratic Malcev algebras with a unique quadratic structure are described in the first part of this pager. In the last part of this paper the extension of a quadratic Malcev algebra which is called a Mc-extension is given; what kind of quadratic Malcev algebra can be obtained by such extension is answered; when two such extensions can be seen identical in the sense that there exists an isometry between them is considered and partly resolved.