Trapping CS₂^2– and S₃^2– between Two Ytterbium Formamidinates

Treatment of [Yb^II(DippForm)₂(thf)_n] (n = 2 (1aYb), n = 1 (1bYb); DippForm = N,N′-bis­(2,6-diisopropylphenyl)­formamidinate), with either excess CS₂ or S₈ gives [Yb^III₂(DippForm)₄(CS₂)] (3) and [Yb^III₂(DippForm)₄(S₂)_0.5/(S₃)_0.5] (4) respectively. 3 is a new addition to an exclusive class of compounds containing the CS₂²⁻ dianion, and 4 is the first crystallographically characterized example of a rare-earth trisulfide complex.