Tetratomic radical

In 1891, a small amount of siUcon carbide was produced bypassing a strong electric current from a carbon electrode through a mixture of clay and coke contained in an iron bowl that served as the second electrode (1). The abrasive value of the crystals obtained were recognized and The Carbomndum Company was founded that year (2). About 10 years earlier tetratomic radicals of siUcon (Si2C202, Si2C2N) had been reported (3). That work also produced some SiC. 

In the next fascicle of his textbook, published at the beginning of 1859, Kolbe came even further toward his erstwhile "typist" enemies. He now advocated the doctrine of atomicity quite explicitly, including, for the first time, referring to the "vieratomig" carbon atom—or rather, since he was an advocate of "equivalents," to the tetratomic carbonyl radical, C2. 

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