For Friday afternoon, a bit of chem-geekery. I recently had occasion to use some copper sulfate, and the bottle I had was marked "large crystals" of the pentahydrate. I have loved the color of that stuff 周五下午，来点化学怪咖。最近我要用一些硫酸铜，瓶子上写着“五水化合物的大晶体”。我喜欢那东西的颜色since  自 I was a kid, and still do. Powdered, you lose a lot of the effect, but the chunks of crystalline stuff are the very definition of blue.我还是个孩子，现在也是。粉末状的，你失去了很多效果，但大块的晶体物质是蓝色的真正定义。

Does anyone know a better one? That's my candidate for the solid phase. In solution, the complex of copper II and pyridine is a good one, a bit more towards royal blue/purple. You can definitely see the change when the pyridine hits it. I can't find a photo of that one on the web; if anyone has one, I'll be glad to post it. More colors to come on other slow Friday afternoons.有人知道更好的吗？这是固相的候选物。在溶液中，铜II和吡啶的配合物是一个很好的配合物，更接近宝蓝色/紫色。当吡啶碰到它时，你可以看到它的变化。我在网上找不到它的照片；如果有人有的话，我很乐意贴出来。在其他缓慢的周五下午会有更多的颜色。

Update: a rare gas-phase blue (!) from the comments. Never seen that before!