 <unk> ( LvH2 ) would be the heaviest chalcogen hydride and the heaviest homolog of water ( the lighter ones being H2S , H2Se , <unk> , and PoH2 ) . <unk> ( polonium hydride ) is a more covalent compound than most metal hydrides because polonium straddles the border between metals and metalloids and has some nonmetallic properties : it is intermediate between a hydrogen halide like hydrogen chloride ( HCl ) and a metal hydride like <unk> ( <unk> ) . <unk> should continue this trend : it should be a hydride rather than a <unk> , but would still be a covalent molecular compound . Spin @-@ orbit interactions are expected to make the Lv – H bond longer than expected simply from periodic trends alone , and make the H – Lv – H bond angle larger than expected : this is theorized to be because the unoccupied 8s orbitals are relatively low in energy and can hybridize with the valence 7p orbitals of livermorium . This is the first molecule to be studied in detail to display this phenomenon , dubbed " <unk> hybridization " , although it was earlier predicted that the same phenomenon would occur with elements 156 – 164 , which would use 7d – 9s – <unk> / 2 hybridizations despite only the 7d ( and occasionally 9s ) orbitals being partially filled . The heavier livermorium dihalides are predicted to be linear , but the lighter ones are predicted to be bent . 
