As seen on the Adonit Website it should be compatible with Ipad 5th Gen.
"What devices will Pixel work with?
- Pixel will work just like your finger on any capacitive touch screen device. Features like pressure sensitivity, palm-rejection, Pixelpoint technology, and use of shortcut buttons require an iOS device with Bluetooth 4.0.
- Compatible Devices: iPhone 4, 4s, 5, 5c, 5s, 6, 6 Plus, 6s, 6s Plus, SE, 8, 8 Plus, X, Xs, Xr, iPad Mini, iPad Mini 2, iPad Mini 3, iPad Mini 4, iPad Air, iPad Air 2, iPad 2017 (5th generation)."
Source: https://www.adonit.net/support/pixel/