Where did you get it? Usually, the LD50 is in the MSDS. You can get the MSDS from the manufacturer's website, if you don't have access to the document itself. Unless you've synthesized the complex yourself -- in which case, its your responsibility to round up a bunch of small mammals and see. Likewise, its not an absolute given that every compound has a known LD50. Can I ask you why you need this info? You didn't eat some by accident, or get it on your skin, or release it into the environment? Because the last one is a totally different regulation, as an example.