Structural chemistry silicides

Parth6, E. and Chabot, B. (1984) Crystal structures and crystal chemistry of ternary rare earth-transition metal borides, silicides and homologues. In Handbook on the Physics and Chemistry of Rare Earths, ed. Gschneidner Jr., K.A. and Eyring, L. (North-Holland, Amsterdam), Vol. 6, p. 113. 

Nesper R, Currao A, Wengert S (1996) Silicon frameworks and Electronic structures of novel solid silicides. In Auner N, Weis J (eds) Organosilicon Chemistry. Wiley-VCH,... 

E. Parthe and B. Chabot, Crystal structures and crystal chemistry of ternary rare earth-transition metal borides, silicides and homologues 113... 

The second example comes from solid-state chemistry, and the coimection with cluster chemistry is less obvious. Despite this, it is an excellent example of how E/M variation can lead to systematic variation in structure and, consequently, to properties. Although the example is taken from solid-state metal borides, the silicides see Silicon Inorganic Chemistry) and phosphides (see Phosphides Solid-state Chemistry) could have been used. 

Although the silicon atom has the same outer electronic structure as carbon its chemistry shows very little resemblance to that of carbon. It is true that elementary silicon has the same crystal structure as one of the forms of carbon (diamond) and that some of its simpler compounds have formulae like those of carbon compounds, but there is seldom much similarity in chemical or physical properties. Since it is more electro-positive than carbon it forms compounds with many metals which have typical alloy structures (see the silicides, p. 789) and some of these have the same structures as the corresponding borides. In fact, silicon in many ways resembles boron more closely than carbon, though the formulae of the compounds are usually quite different. Some of these resemblances are mentioned at the beginning of the next chapter. Silicides have few properties in common with carbides but many with borides, for example, the formation of extended networks of linked Si (B) atoms, though on the other hand few silicides are actually isostructural with borides because Si is appreciably larger than B and does not form some of the polyhedral complexes which are peculiar to boron and are one of the least understood features of boron chemistry. 

Some general systematics on chemical bonding and crystal chemistry have been published by Matkovich and Economy [7], and Aronsson et al. [8, 9], who also refer to the structural similarities in silicides and phosphides. 

Parthd, E. Chabot, B. (1984). Crystal Structures and Crystal Chemistry of Ternary Rare Earth - Transition Metal Borides, Silicides and Homologues in "Handbook on the Physics and Chemistry of The Rare Earths", edited by K.Gschneidner, Jr. and L. R. Eyring, Vol. 6, ppl 13-334, Amsterdam North Holland. 

Pivan, J.Y., Guerin, R. Sergent, M. (1987). A New Classification Scheme to Describe and Predict Structure Types in Pnictide and Silicide Chemistry, J.Solid State Chem. 68, 11-21. 

Aro] Aronsson, B., Lundstroem, T., Engstroem, I., Some Aspects of the Crystal Chemistry of Borides, Boro-Carbides and Silicides of the Transition Metals , Anisotropy in Single-Crystal Refractory Compounds, Vahldiek, F.W, Mersol, S.A., (Eds.), Proc. Int. Symp., Dayton, Ohio, June 13-15, 1967, Plenum Press, New York, 1, 3-22 (1968) (Crys. Structure,... 

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