  Metriplectic systems are state space formulations that have become well-known
under the acronym GENERIC. In this work we present a GENERIC based state space
formulation in an operator setting that encodes a weak-formulation of the field
equations describing the dynamics of a homogeneous mixture of compressible
heat-conducting Newtonian fluids consisting of reactive constituents. We
discuss the mathematical model of the fluid mixture formulated in the framework
of continuum thermodynamics. The fluid mixture is considered an open
thermodynamic system that moves free of external body forces. As closure
relations we use the linear constitutive equations of the phenomenological
theory known as Thermodynamics of Irreversible Processes (TIP). The
phenomenological coefficients of these linear constitutive equations satisfy
the Onsager-Casimir reciprocal relations. We present the state space
representation of the fluid mixture, formulated in the extended GENERIC
framework for open systems, specified by a symmetric, mixture related
dissipation bracket and a mixture related Poisson-bracket for which we prove
the Jacobi-identity.
