In the crown-ether complex, the metal ion fits into the cavity of the crown ether and is solvated by the oxygen atoms. The exterior of the complex is nonpolar, masked by the alkyl groups of the crown ether.
Arrow Alerts. Location-enabled apps and services track your iPhone by periodically querying it for location-based information. They may do this while being used or running in the background on your device. A little arrow appears on the iPhone's upper-right corner to advise you when data is shared. Arrows also appear within the Location Services settings screens to indicate when and what kinds of information was shared with whom.
What does this iPhone symbol mean?. That's a question we hear a lot at Macworld. Most of the time the iPhone and iOS are wonderfully easy to use, but the iPhone does show a lot of symbols, icons and alerts. Getting to know what these symbols mean will help you to understand Apple's iOS operating system. Here's our guide to various iOS symbols so you know what they mean. Updated, 3rd April 2014.