Clearly, we put 2 for each bond, and now we end up having 2 remaining bonding electrons left.

显然，我们在每个键处放上两个电子，那么最后我们还剩下两个成键电子。

麻省理工公开课 - 化学原理课程节选

So, we see is when we use the octet rule to look at fluorine molecule, we're combining two fluorine atoms, and what we end up with is an f f molecule where they're sharing two electrons, so making that covalent bond.

那么，我们看到把八隅体规则用到氟分子上,就是把两个氟原子组合起来，最终得到的氟分子中两个原子,共用一对电子，这就构成了共价键。

麻省理工公开课 - 化学原理课程节选

So for the bond order we want to take 1/2 of the total number of bonding electrons, so that's going to be 4 minus anti-bonding is 4, so we end up getting a bond order that's equal to 0.

键序等于1/2乘以,总的成键电子数，也就是4，减去反键电子数，也就是4。,所以最后得到键序为0。

麻省理工公开课 - 化学原理课程节选

Monthly dividend paying stocks can be an appropriate complement to other monthly-paying securities like closed-end bond funds.

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But in most cases, I think I have a better chance at limiting risk (and ideally boosting returns) by sticking with open-end bond funds like DoubleLine Core Fixed Income (DLFNX), DoubleLine Total Return (DLTNX), Thompson Bond (THOPX), PIMCO Income (PONDX), and PIMCO Foreign Bond US Hedged (PFODX).

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The four iShares index funds (see table below), issued by the Global Investors unit of Barclays (nyse: BCS - news - people ), sport a rock-bottom expense ratio of 0.15 versus open-end bond fund averages of around 1.00 and the 0.20 charged by low-cost leader Vanguard.

FORBES: Magazine Article