The reaction of carbon and CaH2 in a calcium/lithium flux mixture produces crystals of the new compound Ca2LiC3H. This phase forms with a new structure type in tetragonal space group P4/mbm (a = 6.8236(1) Å, c = 3.7518(1) Å, Z = 2, R1 = 0.0151). This is a stuffed variant of the Cs2(NH2)N3 structure, containing hydride anions in octahedral sites; the structure determination by single-crystal X-ray diffraction surprisingly allowed the hydrogen to be detected. The Ca2LiC3H structure also features the rarely seen C3(4-) carbide anion; the protolysis reaction of this compound with ammonium chloride produces C3H4. The electronic properties of Ca2LiC3H were studied by quantum-chemical calculations including band structure and electron localization function (ELF) analysis; the phase is a charge-balanced semiconductor with a calculated band gap of 0.48 eV. This is in agreement with (7)Li, (13)C, and (1)H MAS NMR data, which show resonances in the ionic region instead of the Knight shifted region. ELF analysis of the theoretical nonhydrided Ca2LiC3 structure confirms the ability of these calculations to properly locate hydrides and supports the structural model based on X-ray diffraction data.

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Background: Opioid use in the treatment of musculoskeletal injuries is a complex decision where benefits must be balanced with risk. Previous research has shown an association between higher opioid doses and adverse health effects. The study's objective was to investigate whether opioid prescriptions are associated with increased costs and deaths through an injury mechanism or as a direct result of the opioid prescription.Methods: Data for 144,553 deidentified Ohio Bureau of Workers' Compensation claims from 2010 to 2014 with shoulder, knee, and low back injuries were obtained and followed until 2016. Each claim had associated prescription information. Injury claims were further classified using the allowed diagnoses by single or multiple body areas affected and injury severity ("simple" or "complex"). The outcome variables were medical and indemnity costs, lost days, MaxMED (maximum claim-prescribed daily morphine equivalent dose), and death status. Association between maximum opioid dose with deaths was determined by logistic regression analysis.Results: Several outcome variables, including claim medical and indemnity costs, and the likelihood of claimant death, showed significant associations with the MaxMED.In the analysis of claim deaths, these associations held for all claim types (except complex), even after adjusting for age, gender, surgery, and lost time. Conclusion:The association between increasing opioid doses and deaths for lowseverity diagnoses was disturbing given the lack of demonstrated efficacy of opioids for treatment of minor injuries. A focus on provider education, increased utilization of non-opioids, and early intervention for minor soft-tissue injuries could reduce claims costs, disability, and future deaths.

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