Zintl polyphosphides

The J( Sn- Sn) values are less affected by the nature of the counter cation. Strong ion pairing has also been documented in the polyphosphide Zintl ions, such as LisPy [37]. 

From the pioneering work of Rudolph (group 14 Zintl ions) and Baudler (polyphosphide Zintl ions) to the modem multidimensional techniques used in current research, multinuclear NMR has played a central role in evaluating stmctures. 

The diversity in structure and bonding possible for phosphides is effectively demonstrated by the monophosphides. Monophosphides MP of the group 1 and 2 elements (El, E2) are polyphosphides with i(P ) chains and P2" dumbbells, respectively. Ell and E12 monophosphides are not known. The E3 and E13 monophosphides are the so-called normal compounds with 3x = (M) (see Section 2). With El3, they form the zinc blende structure with tetrahedral heteroatomic bonds. Ternary derivatives such as MgGeP2 and CuSi2P3 have a random distribution of the M atoms, whereas CdGeP2, crystallizes in the ordered chalcopyrite type with a TO[GeP4/2] tetrahedral net (see Section 6.4). The E3 monophosphides form the NaCl structure. CeP is remarkable because of its physical properties (metal-semiconductor transition heavy-fermion behavior). The E14 monophosphides show the break usually observed when passing the Zintl border. Binary lead phosphides are not known SiP and GeP... 

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