The present invention relates to metal-containing compositions with refractive indices of at least 1.5 comprising a metal-containing precursor unit (MU), a prepolymer unit (PU), and a catalyst or an initiator capable of inducing a combining reaction of ethylenically unsaturated functional groups of the metal-containing precursor unit and reactive functional groups of the prepolymer unit. In another embodiment, the composition comprises MU and a catalyst or initiator capable of inducing a combining reaction of the metal-containing precursor units. Both MU and PU contain additional functional groups, which may be selected to impart compatibility with each other and to produce optically clear films. The metal-containing compositions can be used to produce films or articles having a transmittance of at least 90% and index of refraction in the range of 1.5 to 1.8 in the 400-700 nm range of light and 1.5 to 2.4 in the 150-400 nm range of light.