Isotopic splitting

BF3 complexes 1260-1125 (s) 1030-800 (s) Band splitting may be added to isotopic splittings. 

Mixed halometallates [28] can be synthesized RhCl6Br l from the reaction of RhCl - with HBr, or RhBr - with HC1. Individual isomers have been identified in solution by 103 Rh NMR, which can even distinguish between stereoisomers (Figure 2.2) and shows isotopic splitting (Figure 2.3). 

After cocondensation of SiO (1226 cm 1) with alkali metal atoms like Na or K, new bands are detected at 1014 cm 1 (Na) or 1025 cm 1 (K). They can only be attributed to an SiO" anion because of the red shift of the SiO stretching vibration (with respect to that of uncoordinated SiO) and because of different isotopic splittings (28/29/30SiO, Si16/180) [21]. The formation of an ionic species M+(SiO) (M = Na, K) is in line with the results of quantum chemical calculations for the SiO anion (SiO d = 1.49 A, SiO" d = 1.55 A, "electron affinity" SiO + e + 1.06 eV —> SiO") [20]. Taking simple Coulomb interactions into consideration this species is very likely to have a strongly bent structure. The same situation occurs in gaseous NaCN (<(NaNC) = 81.2°) [22],... 

Molecular Cl(H)Si=S (126) was also formed in an argon matrix in a photochemically induced reaction of SiS with HC1. From the isotopic splittings (H/D and 35C1/37C1) of the IR absorptions the Cs structure of the species with silicon as the central atom is deduced. By a normal coordinate analysis a value of 4.83 mdynA-1 is obtained for the SiS force constant, a value which was confirmed by ab initio SCF calculations of the IR spectrum51. 

In the case of sodium or potassium atoms115 the SiO stretching vibration of the reaction product is detected at around 1020 cm-1 (uncoordinated SiO 1226 cm-1). Together with the observed isotopic splittings, the formation of an ionic species M+(SiO)- seems reasonable, this species is very likely to have a strongly bent structure114. 

The nB NMR signals of 231 are shifted 6-18 ppm downfield relative to those of the starting compounds their linewidths, which are greater by a factor of about 5, are consistent with a linear heteroallene structure. Also consistent with such a structure are the isotopically split IR bands at 1850-1900 cm-1, which are assigned to an antisymmetric BN2 vibration. The heteroallene structure has been confirmed by X-ray analysis of 231a.585... 

Nuclear reactors harness the energy from the fission of uranium-235. Nuclear fission occurs when the unstable nucleus of a radioactive isotope splits up, forming smaller atoms and producing a large amount of energy as a result. Scientists believe that the energy comes from the conversion of some of the mass of the isotope. 

The principles of balancing nuclear equations apply to all nuclear reactions. Nuclear fission occurs when a highly unstable isotope splits into smaller particles. Nuclear fission usually has to be induced in a particle accelerator. Here, an atom can absorb a stream of high-energy particles such as neutrons, Jn. This will cause the atom to split into smaller fragments. 

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