[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is a grayish metallic colored powder. Dust from dry powder may be ignited by static electricity. The dry powder reacts with moisture to produce hydrogen, a flammable gas. The heat from this reaction may be sufficient to ignite the hydrogen. It does not appreciably react with large quantities of water."}, {"from": "gpt", "value": "[Hf]"}]